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The Journal of Immunology, 2006, 177: 2775-2783.
Copyright © 2006 by The American Association of Immunologists, Inc.

CD103 Is a Marker for Alloantigen-Induced Regulatory CD8+ T Cells

Elena Uss1,*,§, Ajda T. Rowshani§, Berend Hooibrink{dagger}, Neubury M. Lardy{ddagger}, René A. W. van Lier* and Ineke J. M. ten Berge§

* Department of Experimental Immunology and {dagger} Department of Cell Biology and Histology, Academic Medical Center, Amsterdam, The Netherlands; {ddagger} HLA-Diagnostics Laboratory, Sanquin, Amsterdam, The Netherlands; and § Division of Nephrology, Department of Internal Medicine, Academic Medical Center, Amsterdam, The Netherlands


   Abstract
Top
 Abstract
Introduction
 Materials and Methods
 Results
 Discussion
 Disclosures
 References
 
The {alpha}Ebeta7 integrin CD103 may direct lymphocytes to its ligand E-cadherin. CD103 is expressed on T cells in lung and gut and on allograft-infiltrating T cells. Moreover, recent studies have documented expression of CD103 on CD4+ regulatory T cells. Approximately 4% of circulating CD8+ T cells bear the CD103 molecule. In this study, we show that the absence or presence of CD103 was a stable trait when purified CD103– and CD103+CD8+ T cell subsets were stimulated with a combination of CD3 and CD28 mAbs. In contrast, allostimulation induced CD103 expression on ~25% of purified CD103–CD8+ T cells. Expression of CD103 on alloreactive cells was found to be augmented by IL-4, IL-10, or TGF-beta and decreased by addition of IL-12 to MLCs. The alloantigen-induced CD103+CD8+ T cell population appeared to be polyclonal and retained CD103 expression after restimulation. Markedly, in vitro-expanded CD103+CD8+ T cells had low proliferative and cytotoxic capacity, yet produced considerable amounts of IL-10. Strikingly, they potently suppressed T cell proliferation in MLC via a cell-cell contact-dependent mechanism. Thus, human alloantigen-induced CD103+CD8+ T cells possess functional features of regulatory T cells.


   Introduction
Top
 Abstract
 Introduction
Materials and Methods
 Results
 Discussion
 Disclosures
 References
 
Increasing evidence exists for a protective role for regulatory T cells (Tregs)2 in autoimmune diseases, allergic diseases, and allograft rejection, where they control the potential damaging activity of effector Th1 cells, Th2 cells, or CTLs (1, 2, 3). Tregs can be classified into natural (constitutive) and induced regulatory cells. To the latter category belong CD4+ T regulatory 1 (Tr1) cells and CD4+ Th3 cells, as well as regulatory CD8+ T cells (4).

Natural CD4+CD25+ Tregs have first been described by Sakaguchi et al. (5) as thymic-derived cells that have multiple immunoregulatory properties, including active suppression of self-Ag-reactive T cells, promotion of tolerance to allogeneic bone marrow grafts, and suppression of antitumor immune reactivity. CD4+CD25+ T cells have a low proliferative capacity after allogeneic or polyclonal stimulation and express CTLA4, which delivers a negative signal for T cell activation. Their mechanism of suppression includes cell-cell contact, but secreted cytokines such as TGF-beta and IL-10 may also play a role (6). Expression of the transcription factor Foxp3, a critical regulator of CD4+CD25+ Treg cell development and function, seems the best marker to identify natural CD4+ Tregs (7). Two subsets of inducible CD4+ Tregs have been recognized: Ag-specific Tr1 cells that secrete large amounts of IL-10 and Th3 cells, mainly producing TGF-beta (8, 9, 10).

Although in the past so-called CD8+ T suppressor cells were supposed to play a regulatory role in autoimmune diseases, transplantation, and in protection against cancer (11, 12), only over the last 10 years has this concept re-emerged (13, 14, 15). Until then, efforts to understand the cellular and molecular mechanisms underlying CD8 T cell-mediated immunosuppression were hampered by difficulties in isolating these cells and by a lack of defining markers. The cell surface marker profile described for CD8+ Tregs, such as CD28–, CD45RClow, and CTLA-4+ indicates more that these cells are in an "activated" or "memory" state than that they are associated with a regulatory function. CD8+ Tregs are reported to mediate Ag-specific suppression by production of the cytokines IL-10 and/or TGF-beta and/or by a direct inhibitory action on dendritic cells (16).

The {alpha}Ebeta7 integrin CD103 has initially been described to be expressed on both murine and human CD8+ T lymphocytes localized in intestine, bronchoalveolar fluid, and allograft tissues (17, 18, 19). An important function of this molecule appears to be directing lymphocytes to their ligand E-cadherin, expressed on epithelial cells (20, 21). Although the CD103 molecule can be expressed on alloactivated, graft-infiltrating lymphocytes, this seems not a prerequisite for the cytotoxic function of these cells as in vitro cytotoxicity against alloantigens exerted by sorted CD103–CD8+ T cells equaled that of sorted CD103+CD8+ T cells (22). Moreover, although CD8+ T cells from CD103 knockout mice cannot reach the renal epithelial cells, they show normal cytotoxic capacity (23). Recently, CD103 was shown to be a target of FoxP3 (24) and was found to be expressed on CD4+ Tregs (25, 26). Whether CD103+CD8+ T cells can also exert regulatory functions is currently unknown.

In this study, we show that human CD103+CD8+ T cells can be induced by stimulation with alloantigens in vitro. These cells possess potent suppressive activity in MLC, which is cell-cell contact dependent. CD103+CD8+ T cells secrete IL-10 rather than IFN-{gamma} and maintain their phenotype after restimulation with alloantigen. Thus, CD103 represents a novel marker for a subset of alloantigen-induced regulatory CD8+ T cells.


   Materials and Methods
Top
 Abstract
 Introduction
 Materials and Methods
Results
 Discussion
 Disclosures
 References
 
Cells

PBMC were isolated from whole heparinized blood obtained from 14 healthy donors by Ficoll-Paque density centrifugation (Pharmacia Biotech). The current study was approved by the local medical ethics committee of the Academic Medical Center.

Monoclonal Abs

Biotinylated CD103 mAb and Vbeta3-FITC were purchased from Immunotech and CD103-PE from Caltag Laboratories. CD4– and CD8-PerCP Cy5.5, and CD27-, CD28-, CCR7-, IFN-{gamma}-, IL-4-, IL-10-, streptavidin-PE, mIgG1-PE, and CD8-allophycocyanin were all purchased from BD Immunocytometry Systems. CD45RA-RD1 and streptavidin-allophycocyanin were acquired from BD Pharmingen.

CFSE labeling

PBMC were washed once with PBS containing antibiotics (100 U/ml sodium penicillin (Brocades Pharma) and 100 µg/ml streptomycin sulfate (Invitrogen Life Technologies)) at room temperature before staining. One microliter of CFSE (Molecular Probes; 5 µM stock concentration) was added in 1 ml of PBS-penicillin/streptomycin (pen/strep)/107 cells. Cells were subsequently incubated for 12 min at 37°C. Next, cells were washed three times in PBS-pen/strep at 4°C and resuspended in 1 ml of culture medium.

Culture and stimulation of the cells

All culture experiments were performed in culture medium consisting of IMDM (Invitrogen Life Technologies) containing 10% heat-inactivated autologous human serum, pen/strep, and 2-ME (0.0035% v/v; Merck). MLCs were performed with selected responder-stimulator combinations that gave high proliferative responses in classical MLCs, detected by [3H]thymidine incorporation. Responder PBMC were labeled with CFSE and cultured with irradiated allogeneic stimulator PBMCs or with irradiated autologous PBMCs. When indicated, responder PBMC were stimulated in the presence of CD3 mAb (soluble CLB-T3/4E) and CD28 mAb (CLB-CD28/1).

The precursor frequency (percentage of cells in the initial subset that has undergone one or more divisions after culture) was calculated as follows: [{Sigma}n ≥ 1(Pn/2n)]/[{Sigma}n ≥ 0(Pn/2n)], where n is the division number that cells have gone through and Pn is the number of the cells in division n (27).

To analyze the effect of cytokines on CD103 expression, MLCs were performed in the absence or presence of IL-7 (10 ng/ml; Strathmann), IL-15 (10 ng/ml), IL-4 (10 ng/ml), IL-12 (10 ng/ml), TNF-{alpha} (10 ng/ml), TGF-beta (1 ng/ml) (all from R&D Systems), IL-21 (50 ng/ml; Zymogenetics), IL-10 (10 ng/ml) or IL-17 (10 ng/ml) (both from Sanquin). After 5 days of culture, cells were analyzed by FACSCalibur flow cytometer (BD Biosciences). Responder PBMC stimulated with irradiated autologous cells in the presence of the above-mentioned cytokines were used as controls. Anti-TGF-beta-neutralizing mAb was purchased from R&D Systems and used in a final concentration of 2 µg/ml.

TCR-Vbeta spectratyping

cDNA was synthesized from RNA from equal numbers of sorted CD103+CD8+ and CD103–CD8+ cells. PCR was performed in single TCR-Vbeta PCRs with a TCR-Cbeta primer labeled with a fluorescent dye (Invitrogen Life Technologies) (CAG GCA CAC CAG TGT GGC-FAM) as described previously (28, 29).

Flow cytometric analyses

Immunofluorescent staining and flow cytometry were performed on day 0 and after 5 days of culture. A total of 3 x 105 PBMC were incubated with fluorescent-labeled conjugated mAbs (concentrations according to manufacturer’s instructions) for 30 min at 4°C protected from light. In some cases, this was followed by incubation with a second-step reagent (streptavidin-PE, -allophycocyanin) for 30 min at 4°C. For the cytokine staining, cells were first stimulated in a 24-well plate at 1 x 106 cells/well in 0.5 ml of culture medium with PMA (1 ng/ml), ionomycin (1 µg/ml), and monensin (1 µM) (all from Sigma-Aldrich) for 4 h at 37°C. Cells were washed, and then the same staining procedure as described above was performed using anti-IL-10-PE, anti-IL-4-PE, or anti-IFN-{gamma}-PE Abs.

Evaluation of cytokine production by ELISA

Determination of cytokine concentrations in culture supernatants was performed by ELISA according to manufacturer’s protocols. Reagents for IL-10, IL-2, IFN-{gamma} measurements were obtained from Sanquin. Reagents for TGF-beta measurements were purchased from R&D Systems.

Cell-sorting experiments

T cell subpopulations were purified by FACS sorting. Briefly, unstimulated PBMC or CFSE-labeled PBMC stimulated for 5 days with irradiated allogeneic stimulator PBMC were labeled with CD103-PE, CD4-PerCP Cy5.5, and CD8-allophycocyanin. To identify alloresponsive T cells, a gate was set on the CFSElow population. Next, CD103+CD8+, CD103–CD8+, CD103+CD4+, and CD103–CD4+ subsets were separated with the Aria FACS (BD Biosciences). All sorted subsets were >95% pure.

In vitro suppressor assay

Responder PBMC were labeled with CFSE and cocultured with irradiated allogeneic stimulator PBMC. Purified alloreactive CD103+CD8+, CD103–CD8+, CD103+CD4+, or CD103–CD4+ cells from the same donor were labeled with 1,3-dichloro-9,9-dimethylacridin-2-one succinimidyl ester (DDAO-SE; Molecular Probes) and added to the MLC at different regulator:responder ratios. The assay was performed in round-bottom 96-well microtiter plates. After 5 days of culture, precursor frequency was determined and cells were stained for CD103, CD8, and CD4 to determine the phenotype of proliferating lymphocytes. Blocking Abs were used at the following concentrations: 1 µg/ml anti-IL-10 (BD Pharmingen), 2 µg/ml anti-TGFbeta (R&D Systems), which had been tested for optimal activity in previous experiments.

Transwell assay

To evaluate the role of cell-cell contact in suppressive activity, 24-well plates equipped with a Transwell insert (Costar) consisting of a 200-µl upper well separated from an 800-µl bottom well by a 0.4-µm microporous polycarbonate membrane that had not been pretreated in tissue culture medium were used. The distance between the Transwell membrane and the well bottom was 1 mm. All the cells were resuspended in culture medium. Responder PBMC labeled with CFSE and cocultured with irradiated allogeneic stimulator PBMC were plated in the bottom well of the Transwell system at a concentration of 5 x 105 cells/ml. The top well insert was inoculated with culture medium alone or CD103+CD8+ or CD103–CD8+ T cell population as indicated. After 5 days of culture, cells were stained for CD103 and CD8 and analyzed by FACS.

51Cr-release assay

MLC were performed as described previously (30). Briefly, MLC consisting of responder PBMC and irradiated stimulator cells were used to generate effector cells. After 5 days of proliferation, CD103+CD8+ and CD103–CD8+ alloreactive T cells were sorted and used as effectors. An 8-h 51Cr-release assay was used to detect lysis of stimulator or autologous target cells at varying E:T ratios. Lymphocytes, cultured for 5 days, were used as target cells. The specific percentage of lysis was calculated according to the formula: (ER – SR)/(MR – SR) x100, where ER is the experimental chromium release, SR represents the spontaneous chromium release of target cells in medium alone, and MR equals the maximum chromium release of target cells in 5% saponin solution. In these experiments, the percentage of specific lysis was derived from the E:T ratio of 5:1. All determinations were done in duplicate.

Statistical analysis

The Mann-Whitney U test was used for comparison of two independent groups of observations. The two-tailed Kruskal-Wallis test was used for comparisons of more than two means. Values of p below 0.05 were considered statistically significant.


   Results
Top
 Abstract
 Introduction
 Materials and Methods
 Results
Discussion
 Disclosures
 References
 
CD103+CD8+ T cells derive from CD103–CD8+ T cells upon allostimulation

As reported previously, CD103 defines a subset of CD8+ T cells (31). We found that on average ~4% of freshly isolated CD8+ lymphocytes expressed the CD103 molecule (Fig. 1A). These cells appeared to have a primed phenotype as they lacked CD45RA, CD62L, and chemokine receptor CCR7 (data not shown). To investigate the stability of CD103 expression on CD8+ T cells, we purified CD103+CD8+ and CD103–CD8+ subsets from PBMC and stimulated them with a combination of CD3 and CD28 mAb for 3 days. Both populations maintained their phenotype (Fig. 1B). In contrast, in alloantigen-stimulated cultures, an up-regulation of the CD103 molecule was found on CD103–CD8+ T cells since 31.44 ± 8.49% (mean ± SD of nine donors tested) of these cells acquired CD103 expression. Additionally, Fig. 1B shows that both CD103– and CD103+ CD8+ T can respond to alloantigens, albeit CD103– cells have a more potent proliferative response. To address the influence of soluble factors on expression of CD103 by CD103–CD8+ T cells, we conducted a Transwell assay. CD103–CD8+ T cells stimulated with a combination of CD3 and CD28 mAb, and separated with a semipermeable membrane from allostimulated PBMC, up-regulated CD103 (6.8 ± 2.3% of CD8+ T cells became CD103+) (Fig. 1CII), although to a lesser extent than when they were stimulated with alloantigen in control cultures without semipermeable membrane (14.7 ± 3.9% of CD103+CD8+ T cells) (Fig. 1CIII). Similar results were obtained when CD103–CD8+ T cells were stimulated with CD3/CD28 mAb and to which supernatant from a 5-day allostimulated culture was added (Fig. 1CIV).


Figure 1
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  		FIGURE 1. CD103+CD8+ T cells derive from CD103–CD8+ T cells upon allostimulation. A, CD103 defines a subset of circulating resting CD8+ T cells. The dot plots represent T cells gated on CD8+ T cells. One representative experiment of nine is shown. B, CD103 is up-regulated by allostimulation. Purified CD103+CD8+ and CD103–CD8+ T cells were labeled with CFSE and stimulated with a combination of CD3 and CD28 mAb (anti-CD3/anti-CD28) for 3 days, or with alloantigen for 5 days as indicated. Dot plots (gated on CD8+ T cells) represent the phenotype of the subsets in nondivided (left panel) and divided (middle panel) populations based on CFSE dilution on days 3 and 5, respectively. The x-axis shows log fluorescence of CD8-allophycocyanin, the y-axis shows log fluorescence of CD103-PE. The right panel shows the divisions of these cells. One representative experiment of three is shown. C, Up-regulation of CD103 is dependent on soluble factors. Purified CD103–CD8+ T cells were labeled with CFSE and stimulated with a combination of CD3 and CD28 mAb for 3 days. To determine the influence of alloantigen-induced soluble factors, responder CD103–CD8+ T cells were plated in the top insert of a Transwell system at a concentration of 2 x 105 cells/200 µl. The bottom well was inoculated with culture medium alone (I) or with PBMC cocultured with irradiated allogeneic stimulator PBMC (II). Purified CD103–CD8+ T cells stimulated with alloantigen for 5 days were used as a control (III). In parallel, purified CD103–CD8+ T cells stimulated with CD3/CD28 mAb were cultured in the presence of the supernatant from a 5 day alloculture (IV). Dot plots represent the phenotype of CD8+ T cells (one of two independent experiments). The x-axis shows log fluorescence of CD8-allophycocyanin; the y-axis shows log fluorescence of CD103-PE.

 
To obtain more insight into the details of alloantigen-induced up-regulation of CD103, MLCs starting with unseparated PBMC were performed (Fig. 2, A and B). Because the previous experiment showed that CD103+ T cells represented only a minute subset of the circulating CD8+ T cell pool and CD103–CD8+ T cells had a superior mitogenic response upon allostimulation, these experiments largely reflected de novo expression of CD103 on formerly CD103– lymphocytes. Following stimulation with irradiated allogeneic cells, CD8+ T cells already up-regulated CD103 at day 3 when 26.33 ± 14.97% (mean ± SD) expressed the CD103 molecule (Fig. 2C). Expression increased gradually with a peak on day 5 (53.63 ± 13.81%, Fig. 2C). As we described previously, alloreactive CD8+ T cells bear the phenotype of effector T cells (32). Next to this, CD4+ cells up-regulated CD103 less significantly (p < 0.05), because only 10.77 ± 5.23% of alloreactive CD4+ T cells became CD103 positive at day 5 (Fig. 2B). Thereafter, the expression of CD103 in both T cell subsets slightly decreased, yielding 37.77 ± 16.09% CD103+CD8+ (Fig. 2C) and 8.53 ± 3.71% CD103+CD4+ T cells on day 7 of culture (data not shown). Neither CD4+ nor CD8+ T cells expressed CD103 after autologous stimulation (data not shown). Based on the diminution of CFSE fluorescence, expression of CD103 on CD8+ alloreactive T cells increased with the number of cell divisions (Fig. 2D).


Figure 2
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  		FIGURE 2. After allogeneic stimulation in vitro, CD103 is mainly expressed on divided CD8+ T lymphocytes. PBMC were labeled with CFSE and cultured with irradiated allogeneic or autologous PBMC. Flow cytometric analysis was performed on day 5 of culture. The subset distribution was assessed by staining with CD4-PerCP Cy5.5, CD8-PerCP Cy5.5, CD27-PE, and CD103-bio-allophycocyanin. A, Dot plots represent alloreactive T cells gated on CD4+ T cells at days 0 and 5 of culture. Analysis was done in undivided and divided subsets. The x-axis shows log fluorescence of CD103-bio-allophycocyanin; the y-axis shows log fluorescence of CD27-PE. B, The mean percentage of CD103+ cells ± SD from 14 independent experiments is shown. {blacksquare}, The mean percentage of CD103+ cells within the CD4+ alloreactive T cells; Figure 2, the mean percentage of CD103+ cells within the CD8+ subset. Differences in the percentage of CD103+ cells within alloreactive CD4+, respectively, CD8+ cells between days 0 and 5 of culture were significant (p < 0.05), as was the difference between CD103+ cells in the divided CD4+ and CD8+ T cell subsets at day 5, indicated by an asterisk (*). C, Time course of alloantigen-induced CD103 expression. Bars represent the mean percentage of CD103+CD8+ alloreactive T cells ± SD (y-axis) of three independent experiments as determined on days 3–7 after initiation of the MLC (x-axis). D, Expression of CD103 on CD8+ alloreactive T cells increases with the number of cell divisions. The x-axis shows log fluorescence of CFSE; the y-axis shows log fluorescence of CD103-PE.

 
CD103 expression on alloreactive CD8+ T cells is increased in the presence of TGF-beta, IL-4, and IL-10 but is down-regulated by IL-12 in MLCs

To assess the influence of cytokines on CD103 expression, standard MLCs were performed in the presence or absence of different cytokines. In preliminary experiments, the optimal concentration of these cytokines had been determined (data not shown). Confirming previous studies (31), addition of TGF-beta to MLC increased the percentage of CD8+ T cells expressing CD103 to >90% (Fig. 3A). Only two of the other cytokines tested also had a significant effect on CD103 expression on alloreactive cells. IL-4 increased the percentage of CD103+-expressing CD8+ T cells from 45.41 ± 10.61% to 75.69 ± 21.91% (four donors, p < 0.05, Fig. 3B). Expression of CD103 on alloreactive CD8+ T cells stimulated in the presence of IL-12 was significantly lower than in the control cultures (17.6 ± 12.1% vs 45.41 ± 10.61%). Addition of IL-10 did not have a significant effect on the frequency of T cells expressing CD103 (Fig. 3B); however, the amount of CD103 expressed per cell was clearly increased as evidenced by the higher intensity of CD103 staining (Fig. 3C). To assess the role of TGF-beta in the elevated expression of CD103 induced by IL-4 and IL-10, MLCs were performed in the presence of both the aforementioned cytokines and a neutralizing anti-TGF-beta mAb (final concentration 2 µg/ml). As a control, MLCs were performed in the presence of rTGF-beta in a final concentration of 1 ng/ml together with the anti-TGF-beta mAb in a final concentration of 2 µg/ml. Addition of the blocking anti-TGF-beta mAb did not influence the amount of CD103 expressed on alloreactive T cells induced by IL-4 or IL-10. Likewise, TGF-beta-production was not influenced by the addition of rIL-12 at a final concentration of 10 ng/ml. (data not shown). Addition of other cytokines such as IL-7, IL-15, IL-21, TNF-{alpha}, or IL-17 did not significantly affect CD103 expression (Fig. 3B).


Figure 3
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  		FIGURE 3. CD103 expression on alloactivated CD8+ T cells is increased when cocultured in the presence of TGF-beta, IL-4, or IL-10 and decreased by IL-12. A, Expression of CD103 on alloreactive CD8+ T cells on day 5 of MLC, performed in the absence or presence of several cytokines. x-axis, Log fluorescence CD103-PE; filled histograms, isotype control; bold histograms, CD8+ alloreactive T cells. One representative experiment of four experiments is shown. B, The bars represent the mean percentage ± SD of CD103+CD8+ T cells at day 5 of MLC in the absence or presence of different cytokines (four experiments). Statistical significance is indicated by an asterisk (*, p < 0.05). C, The bars represent mean fluorescence intensity (MFI) of CD103 on CD103+CD8+ T cells on day 5 of MLC in the absence or presence of different cytokines. The mean percentage ± SD from four independent experiments is shown. Statistical significance is indicated by an asterisk (*, p < 0.05).

 
Functional properties of CD103+CD8+ and CD103–CD8+subsets

Having established that CD103+CD8+ T cells specifically expand upon alloantigenic stimulation, subsequent experiments were performed to determine the Vbeta usage, stability, and functional properties of this subset.

The TCR Vbeta repertoire of sorted CD103+CD8+ T cells was determined and compared with that of CD103–CD8+ T cells to investigate the clonal composition of the CD103+CD8+ T population. As shown in Fig. 4A, although somewhat less diverse than the CD103–CD8+ fraction, CD103+CD8+ T cells used a broad spectrum of Vbeta families inferring that this population contained multiple clones that have expanded in response to alloantigen exposure.


Figure 4
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  		FIGURE 4. CD103+CD8+ T cells are a polyclonal population with low proliferative capacity. A, TCR Vbeta repertoire of sorted CD103+CD8+ and CD103–CD8+ T cells. After allostimulation for 5 days, CD8+ cells were sorted into CD103+CD8+ and CD103–CD8+ subsets. The TCR Vbeta repertoire of sorted CD103+CD8+ T cells was determined and compared with that of CD103–CD8+ T cells. *, Vbeta expressed differentially between CD103+CD8+ and CD103–CD8+ populations. B, The difference in Vbeta3 expression between CD103+CD8+ and CD103–CD8+ T cells was confirmed by FACS analysis of alloreactive T cells. Dot plots represent alloreactive CD8+ T cells. The x-axis shows log fluorescence of Vbeta3-FITC; the y-axis shows log fluorescence of CD103-PE. One representative experiment of two is shown. C and D, Analysis of stability of CD103 expression. CD103+CD8+ and CD103–CD8+ subsets, sorted after 5 days of allostimulation, were labeled with CFSE and restimulated with alloantigen. After 5 days of restimulation, FACS analysis was performed. Dot plots of the left panel represent sorted CD103+CD8+ T cells (C) and sorted CD103–CD8+ T cells (D) restimulated with alloantigen, showing maintenance of phenotype. The right panels show hardly any proliferative capacity of the CD103+CD8+ T cell subset compared with the CD103–CD8+ T cell subset. One representative experiment of three is shown.

 
As compared with their expression in the CD103–CD8+ T cell population, expression of Vbeta3, Vbeta10, and Vbeta20 was significantly reduced in the CD103+CD8+ T cell population (Fig. 4A). The lower expression of Vbeta3 by CD103+CD8+ T cells was confirmed by FACS analysis (Fig. 4B). To examine the stability of CD103+ expression on alloantigen-expanded CD8+ T cells, sorted CD103+CD8+ T cells were labeled with CFSE and restimulated with alloantigen or a combination of CD3 and CD28 mAb. Irrespective of the stimulus, acquired CD103 expression appeared to be a stable trait as sorted CD103+CD8+ remained predominantly CD103+; purified CD103–CD8+ T cells also retained their phenotype (Fig. 4, C and D). On day 7 after restimulation, CD103 expression on the sorted CD103+ T cells subsequently went down, but no changes were observed regarding CD103 expression on the sorted CD103– subset (data not shown). Remarkably, based on the diminution of CFSE fluorescence, CD103+CD8+ T cells hardly proliferated, whereas CD103–CD8+ cells divided up to four times after allogeneic restimulation (Fig. 4, C and D).

Next, the ability of CD103+CD8+ T cells to produce inflammatory and tolerogenic cytokines was investigated. To this end, CD8+ T cells from MLC after 5 days of stimulation were sorted into CD103+ and CD103– subsets and restimulated with alloantigen for 5 days. Production of the cytokines by the purified subsets as measured by ELISA showed that IL-10 and TGF-beta were produced by both subsets, whereas IFN-{gamma} was significantly higher in the supernatants of CD103–CD8+ T cells (Fig. 5A). In accordance with this observation, we found that production of IFN-{gamma}, determined by FACS, predominantly correlated with the absence of CD103 expression on T cells (53.87 ± 8.03% of CD103–CD8+ cells produced IFN-{gamma} vs 14.89 ± 4.91% of CD103+CD8+ T cells, Fig. 5B).


Figure 5
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  		FIGURE 5. Functional properties of alloreactive CD103+CD8+ and CD103–CD8+subsets. A, Cytokine profiles of the alloreactive CD103+CD8+ and CD103–CD8+ T cell subsets. Sorted alloreactive CD103+CD8+ or CD103–CD8+ T cell subsets were restimulated with alloantigen for 5 days. The production of the tolerogenic cytokines IL-10 and TGF-beta and the inflammatory cytokine IFN-{gamma} by purified subsets was detected by ELISA. The bars represent mean ± SD of the concentration of IL-10, IFN-{gamma}, or TGF-beta in the culture supernatants. The mean percentage ± SD from three independent experiments is shown. Statistical significance is indicated by an asterisk (*, p < 0.05). B, Intracellular cytokine expression. PBMC were labeled with CFSE and stimulated with alloantigen. After 5 days of culture, expression of the tolerogenic cytokine IL-10 and the inflammatory cytokine IFN-{gamma} was analyzed by FACS. Dot plots represent alloreactive T cells gated on CD8+ T cells. The x-axis shows log fluorescence of CD103-bio-allophycocyanin; the y-axis shows log fluorescence of IL-10- and IFN-{gamma}-PE. One representative experiment of four is shown. C, Cytotoxic capacity of CD103–CD8+ and CD103+CD8+ alloreactive T cells. Cytotoxicity was measured by the percentage of 51Cr release, as depicted on the y-axis. Alloreactive CTL were generated in MLC after 5 days of allogeneic stimulation and CD103+CD8+ ({diamondsuit}) and CD103–CD8+ alloreactive T cells ({blacksquare}) were sorted and used as effectors. The cytotoxic activity of the total alloreactive lymphocyte pool is shown as {blacktriangleup}. Different numbers of alloreactive effector cells are depicted on the x-axis. One representative experiment of three is shown.

 
Finally, we investigated whether CD103+CD8+ and CD103–CD8+ populations differed in cytotoxic potential. After separation of the alloreactive cells into CD103+CD8+ and CD103–CD8+ populations, their lytic capacity against allogeneic target cells was tested (see Materials and Methods). As shown in Fig. 5C, CFSElow-negCD103–CD8+ T cells are superior in cytotoxic activity compared with CD103+CD8+ T cells.

The CD103+CD8+ subset possesses regulatory activity

Given that the CD103+CD8+ subset was able to produce IL-10, but no IFN-{gamma}, combined with the observation that CD103+CD8+ T cells had low proliferative capacity, we examined the possible regulatory capacity of this subset. Alloexpanded purified subsets were tested for their suppressive activity in MLCs. Responder PBMC were labeled with CFSE and stimulated with irradiated allogeneic PBMC for 5 days. Addition of CD103+CD8+ T cells, autologous to the responder PBMC, from a regulator:responder ratio of 1:10, considerably decreased the precursor frequency from 3.88 ± 1.81% in control allostimulated cultures to 2.16 ± 1.89% in the experimental cultures (p < 0.005, Fig. 6A). Addition of CD103–CD8+ cells to the culture did not influence the precursor frequencies of allostimulated cells (Fig. 6A). Notably, CD103+CD4+ T cells also showed regulatory capacity as has been reported previously (26). Added at a 1:2 ratio to the MLC, CD103+CD4+ T cells significantly inhibited the proliferation of alloreactive cells (precursor frequency 1.03 ± 0.48%) compared with control cultures (precursor frequency 3.46 ± 0.45%) (Fig. 6B). Thus, the CD103+CD8+ subset showed a similar inhibitory effect in in vitro suppressor assay as CD103+CD4+ cells. To examine whether suppressive capacity is an intrinsic characteristic of alloactivated CD103+CD8+ T cells or whether it is a feature of all CD8+ T cells bearing the CD103 molecule, we purified CD103+CD8+ T cells from freshly isolated PBMC and tested their inhibitory ability. Freshly isolated CD103+CD8+ T cells significantly inhibited proliferation of polyclonally stimulated PBMC (combination of CD3 and CD28 Abs) at a regulator:responder ratio 1:2 whereas CD103–CD8+ T cells did not (data not shown).


Figure 6
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  		FIGURE 6. CD103+CD8+ T cells have a strong regulatory capacity in vitro, which is not mediated by soluble IL-10 or TGF-beta but appeared cell-cell contact dependent and Ag-nonspecific. Purified CD103+CD8+, CD103–CD8+, CD103+CD4+, and CD103–CD4+ T cells were tested for their suppressive activity in in vitro MLC. A, Responder PBMC were labeled with CFSE and cocultured with irradiated allogeneic stimulator PBMC. Purified CD103+CD8+ (Figure 6) or CD103–CD8+ (Figure 6) were added to the MLC at different regulator:responder ratios, namely 1:20, 1:10, 1:5, 1:2, and 1:1 (x-axis). As a positive control, PBMC were stimulated with alloantigen only ({blacksquare}). On the y-axis, the mean percentage of precursor frequencies ± SD from five separate experiments is represented. Statistical significance is indicated by an asterisk (*, p < 0.05). B, Purified CD103+CD4+ (Figure 6) or CD103–CD4+ (Figure 6) T cells were added to MLC at a regulator:responder ratio of 1:2. As a positive control, PBMC were stimulated with alloantigen only ({blacksquare}). The y-axis shows the mean percentage of precursor frequencies ± SD from two separate experiments. C, CFSE-labeled PBMC were cocultured in MLC together with purified CD103+CD8+ T cells (Figure 6) at a regulator:responder ratio of 1:2 in the presence or absence of neutralizing Abs against IL-10 or TGF-beta. As a positive control, PBMC were stimulated with alloantigen ({blacksquare}). The y-axis shows the mean percentage of precursor frequencies ± SD from three independent experiments. D, Responder PBMC labeled with CFSE and cocultured with irradiated allogeneic stimulator PBMC were plated in the bottom well of a Transwell system at a concentration of 5 x 105 cells/ml. The top well insert was inoculated with culture medium alone or with purified CD103+CD8+ or CD103–CD8+ T cell population as indicated. The y-axis shows precursor frequencies ± SD from three independent experiments. Statistical significance is indicated by an asterisk (*, p < 0.05). E, To evaluate Ag specificity of the CD103+CD8+ regulatory T cells, purified XY CD103+CD8+(Figure 6), XZ CD103+CD8+({square}), XY CD103–CD8+ (Figure 6), and XZ CD103–CD8+ (Figure 6) T lymphocytes were added to the MLC at different regulator/responder ratios, as depicted on the x-axis (see explanation in Results). As a positive control, PBMC were stimulated with alloantigen only ({blacksquare}). The y-axis shows the mean percentage of precursor frequencies ± SD from three independent experiments. Statistical significance is indicated by an asterisk (*, p < 0.05).

 
We next analyzed whether the inhibitory effect of the CD103+CD8+ subset is mediated by the immunosuppressive cytokines IL-10 and/or TGF-beta. Addition of anti-IL-10 or anti-TGF-beta-neutralizing Abs to the in vitro suppressive assay did not affect the inhibition of proliferation of alloactivated cells by the CD103+CD8+ subset (Fig. 6C). In previous experiments, anti-IL-10 and anti-TGF-beta mAbs were shown to inhibit the function of IL-10 and TGF-beta, respectively (data not shown). To address the involvement of membrane-bound compounds, we studied the effect of cell-cell interaction on suppressive activity of CD103+CD8+ T cells. We found that the inhibitory function of this population depends on cell-cell contact as no suppression of T cell proliferation was observed when the regulatory cells were separated from MLC by a Transwell insert (Fig. 6D).

In vitro-activated CD103+CD8+ T cells are Ag nonspecific in their ability to suppress T cell proliferation

To investigate whether suppression by alloactivated CD103+CD8+ T cells is Ag specific, we designed the following experiments. For the generation of CD103+CD8+ regulatory cells, we used PBMC from completely HLA-mismatched donors. Two MLC combinations were used (responder X stimulated with Y and responder X stimulated with Z), from which two types of regulatory CD103+CD8+ T cells were isolated by cell sorting (XY CD103+CD8+ and XZ CD103+CD8+). Next, a suppressor assay was performed in which responder PBMC (X) were labeled with CFSE and cultured with irradiated allogeneic stimulator PBMC (Y) for 5 days. When XY CD103+CD8+ T cells were added in several regulator:responder ratios, the alloresponse was inhibited by 60–80%. This alloresponse could also be inhibited in the presence of XZ CD103+CD8+ T cells, although to a lower extent (Fig. 6E), indicating that suppression of the immune response by CD103+CD8+ cells was not dependent upon the presence of a specific allopeptide in the culture. Addition of XZ CD103–CD8+ T lymphocytes as well as addition of XY CD103–CD8+ T cells hardly affected the precursor frequency of allostimulated cells (Fig. 6E).


   Discussion
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
Disclosures
 References
 
In the present study, we show that the integrin CD103 is up-regulated on human CD8+ T cells after stimulation by alloantigen in vitro, which is dependent on soluble factors. In contrast, the up-regulation of CD103 was far less after nonspecific polyclonal stimulation, suggesting a role for monocyte-derived factors in the induction of CD103 expression. CD103 appeared to be mainly expressed on dividing CD8+ T cells, which, as we previously showed, bear the phenotype of effector T cells (32). Up-regulation of CD103 on in vitro-alloactivated T cells was augmented by TGF-beta, IL-4, or IL-10 and diminished by IL-12. Secretion of the tolerogenic cytokine IL-10 was slightly higher in the sorted CD103+CD8+ T cell subset than in the CD103–CD8+ T cell subset, but CD103–CD8+ T cells secreted considerably higher amounts of IFN-{gamma}. CD103+CD8+ T cells were polyclonal, had a low proliferative and cytotoxic capacity compared with CD103–CD8+ T cells, but displayed a strong suppressive activity in the MLC. This suppressive effect of CD103+CD8+ T cells appeared not to be mediated by IL-10 or TGF-beta, but was found to be cell-cell contact dependent. Addition of CD103+CD8+ T cells stimulated by third-party cells inhibited the proliferative capacity of alloactivated cells, though to a lesser extent than did alloantigen-specific CD103+CD8+ T cells.

CD103 is the receptor for E-cadherin, which is expressed on epithelial cells, including renal tubular epithelial cells. As such, in renal allografts CD103 may direct graft-infiltrating lymphocytes to tubular epithelial cells, which are the main target for apoptotic cell death during allograft rejection (33, 34). Independent from its role in migration of immune cells, CD103 is also a marker of T cell activation (35). In support of this, effector-memory tonsil-resident CD103+CD8+ T cells were found to be more reactive to their cognate Ag than the CD103–CD8+ T cells, which permits rapid recall responses at even low Ag concentrations, suggesting a role of CD103 not only in homing and retention of T cells at epithelial sites but also in promoting T cell function (36). Whether the CD103 molecule also directly contributes to the regulatory function of natural Tregs (26) and CD8+ Tregs (this manuscript) is unknown. Recently, CD103 was demonstrated to be a biomarker for murine CD8+ suppressor T cells. These cells required IFN-{gamma} to suppress CD4+ T cell division (37). A putative regulatory function for CD103-expressing CD8+-alloreactive T cells appears to accord with the absence of CD103+CD8+ T cells in biopsies from rat renal allografts undergoing unmodified acute rejection (38) and from patients with acute rejection (39). In contrast, CD103+CD8+ T cells are mainly present in late allograft rejection, occurring beyond the first 6 mo after transplantation, as well as in biopsies with signs of chronic rejection (40). Thus, during ongoing, smouldering alloactivation in a predominant Th2 microenvironment, as is the case during chronic allograft rejection (41), negative regulatory signals may prevent the alloresponse from inducing an acute inflammatory reaction. In this respect, studies to a possible involvement of CD103+CD8+ T cells in subclinical allograft rejection, in which no deterioration of allograft function occurs, despite the presence of a clear inflammatory cellular infiltrate, will be of particular interest (34).

Whereas about half of the in vitro alloactivated CD8+ T cells expressed the CD103 molecule, the tolerogenic cytokines TGF-beta, IL-4, and IL-10 markedly increased the percentage and/or the intensity of CD103 expression. Other in vitro studies have also indicated an important role for TGF-beta in the up-regulation of CD103 expression on CD8+ effector T cells (31). Hadley and colleagues (42) demonstrated that up-regulation of CD103 expression by alloreactive CD8+ cells occurred subsequent to entry into the graft, which was dependent on the local level of TGF-beta. The enhancing effect of IL-4 on CD103 expression of allogeneic-stimulated CD8+ T cells is in line with the described up-regulation of CD103 on both CD4+ and CD8+ cells after in vitro stimulation by CD3 mAbs in the presence of this cytokine (43). IL-4 may exert its effect on CD103 expression directly or indirectly by induction of TGF-beta production as has been described for murine T cells (44). However, we did not find a blocking effect of anti-TGF-beta mAb on the expression of CD103 induced by IL-4. Our finding of down-regulation of CD103 expression on CD8+ T cells after allogeneic stimulation in vitro in the presence of IL-12 was also observed after stimulation of T cells with CD3 mAbs in the presence of this cytokine (43). Altogether, these findings indicate that a Th2 more than a Th1 microenvironment favors CD103 expression, which supports its role in late and chronic rejection more than in acute renal allograft rejection. CD103 might well be differentially expressed on T cytotoxic (Tc)1 and Tc2 CD8+ T cells, where CD103-expressing CD8+ CTLs, possibly of the Tc2 type, are more involved in a regulatory function than in a cytotoxic one. Indeed, in agreement with data from the literature (22), we showed that the cytotoxic capacity of CD103+CD8+ T cells against alloantigens is less than that of CD103–CD8+ T cells, indicating no role for CD103 in allocytotoxic effector function.

In this study, we show that expression of Vbeta3, Vbeta10, and Vbeta20 was significantly reduced in the CD103+CD8+ alloreactive T cell population as compared with that in the CD103–CD8+ T cell population. Thus, not all specificities are present within the alloreactive CD103+CD8+ T cell population. Several studies have provided evidence for a restricted Vbeta gene usage in response to DR synthetic peptides presented in the context of self MHC molecules, i.e., allostimulation via the indirect pathway (45, 46). Preferential activation of T cell subsets by specific DR alleles may play an important role in alloresponses as occur in MLRs and in organ transplantation.

Tregs may exert their suppressive function by several mechanisms. Regardless of their mechanism of action, Tregs may operate both at the level of T effector cells and at the level of APCs by decreasing the expression of MHC class II and costimulatory molecules (6). Regarding CD8+ Tregs, IL-10 has been described to be involved in their capacity to suppress T cell proliferation (47). The CD103-bearing CD8+ alloreactive lymphocytes that we here describe produced IL-10 and TGF-beta, but could not be inhibited in their immunosuppressive activity by anti-IL-10 or anti-TGF-beta mAbs, suggesting an IL-10- and TGF-beta-independent mechanism of suppression. In contrast, the suppressive effect of CD103+CD8+ T cells appeared to be cell-cell contact dependent. Recent reports have re-examined a role of cell death as a mechanism of suppression by Treg (48, 49). Grossman et al. (50) indicates that human CD4+CD25+ Treg mediate their suppressive effects via death induced by a granzyme A-perforin-dependent mechanism. Granzyme B was shown to be involved in contact-mediated suppression by murine CD4+CD25+ Treg (51). We demonstrate that CD103+CD8+ alloreactive T cells were less cytotoxic than CD103–CD8+ T cells and therefore cytotoxicity is not likely to be involved in the mechanism of suppression by CD103+CD8+ T cells. Further studies are needed to elucidate their mechanism of action. The absence of an appropriate cosignal, the presence of immature or plasmacytoid dendritic cells, or the presence of specific cell surface or soluble molecules may all be operational (6). In contrast, high cytotoxicity of the CD103–CD8+ T cells might be an explanation for a slightly decreased proliferative capacity of allostimulated PBMC in the presence of sorted allogeneic CD103–CD8+ T cells.

It is still unsolved whether Tregs need a second encounter with the same peptide/Ag to become functional. In this study, we demonstrate that once activated, CD103+CD8+ alloreactive Tregs are able to suppress T cell reactivity. It may be conceived that during a local response, CD103 initially serves to retain alloantigen-induced CD8+ Treg cells at the graft site and later functions on Tregs that exert their role as soon as alloantigen is recognized.


   Acknowledgments
 
We thank Si-La Yong for her excellent technical support. We are grateful to Drs. Eddy Wierenga and Ester M. M. van Leeuwen for critical reading of the manuscript.


   Disclosures
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 Disclosures
References
 
The authors have no financial conflict of interest.


   Footnotes
 
The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked advertisement in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

1 Address correspondence and reprint requests to Dr. Elena Uss, Department of Experimental Immunology, Academic Medical Center, University of Amsterdam, L1-110, 1105 AZ Amsterdam, The Netherlands. E-mail address: a.uss{at}amc.uva.nl Back

2 Abbreviations used in this paper: Treg, T regulatory cell; Tr1, T regulatory 1; pen/strep, penicillin/streptomycin; Tc, T cytotoxic. Back

Received for publication December 5, 2005. Accepted for publication May 17, 2006.


   References
Top
 Abstract
 Introduction
 Materials and Methods
 Results
 Discussion
 Disclosures
 References
 

  1. Chen, C., W. H. Lee, P. Yun, P. Snow, C. P. Liu. 2003. Induction of autoantigen-specific Th2 and Tr1 regulatory T cells and modulation of autoimmune diabetes. J. Immunol. 171: 733-744. [Abstract/Free Full Text]
  2. Akdis, M., J. Verhagen, A. Taylor, F. Karamloo, C. Karagiannidis, R. Crameri, S. Thunberg, G. Deniz, R. Valenta, H. Fiebig, et al 2004. Immune responses in healthy and allergic individuals are characterized by a fine balance between allergen-specific T regulatory 1 and T helper 2 cells. J. Exp. Med. 199: 1567-1575. [Abstract/Free Full Text]
  3. Graca, L., A. Le Moine, S. P. Cobbold, H. Waldmann. 2003. Dominant transplantation tolerance. Curr. Opin. Immunol. 15: 499-506. [Medline]
  4. Mills, K. H.. 2004. Regulatory T cells: friend or foe in immunity to infection?. Nat. Rev. Immunol. 4: 841-855. [Medline]
  5. Sakaguchi, S., N. Sakaguchi, M. Asano, M. Itoh, M. Toda. 1995. Immunologic self-tolerance maintained by activated T cells expressing IL-2 receptor {alpha}-chains (CD25): breakdown of a single mechanism of self-tolerance causes various autoimmune diseases. J. Immunol. 155: 1151-1164. [Abstract]
  6. Vigouroux, S., E. Yvon, E. Biagi, M. K. Brenner. 2004. Antigen-induced regulatory T cells. Blood 104: 26-33. [Abstract/Free Full Text]
  7. Fontenot, J. D., M. A. Gavin, A. Y. Rudensky. 2003. Foxp3 programs the development and function of CD4+CD25+ regulatory T cells. Nat. Immunol. 4: 330-336. [Medline]
  8. Chen, Y., V. K. Kuchroo, J. Inobe, D. A. Hafler, H. L. Weiner. 1994. Regulatory T cell clones induced by oral tolerance: suppression of autoimmune encephalomyelitis. Science 265: 1237-1240. [Abstract/Free Full Text]
  9. Groux, H., A. O’Garra, M. Bigler, M. Rouleau, S. Antonenko, J. E. de Vries, M. G. Roncarolo. 1997. A CD4+ T-cell subset inhibits antigen-specific T-cell responses and prevents colitis. Nature 389: 737-742. [Medline]
  10. McGuirk, P., C. McCann, K. H. Mills. 2002. Pathogen-specific T regulatory 1 cells induced in the respiratory tract by a bacterial molecule that stimulates interleukin 10 production by dendritic cells: a novel strategy for evasion of protective T helper type 1 responses by Bordetella pertussis. J. Exp. Med. 195: 221-231. [Abstract/Free Full Text]
  11. Fowler, D. H., J. Breglio, G. Nagel, M. A. Eckhaus, R. E. Gress. 1996. Allospecific CD8+ Tc1 and Tc2 populations in graft-versus-leukemia effect and graft-versus-host disease. J. Immunol. 157: 4811-4821. [Abstract]
  12. Martin, P. J.. 1993. Donor CD8 cells prevent allogeneic marrow graft rejection in mice: potential implications for marrow transplantation in humans. J. Exp. Med. 178: 703-712. [Abstract/Free Full Text]
  13. Gilliet, M., Y. J. Liu. 2002. Generation of human CD8 T regulatory cells by CD40 ligand-activated plasmacytoid dendritic cells. J. Exp. Med. 195: 695-704. [Abstract/Free Full Text]
  14. Sarantopoulos, S., L. Lu, H. Cantor. 2004. Qa-1 restriction of CD8+ suppressor T cells. J. Clin. Invest. 114: 1218-1221. [Medline]
  15. Najafian, N., T. Chitnis, A. D. Salama, B. Zhu, C. Benou, X. Yuan, M. R. Clarkson, M. H. Sayegh, S. J. Khoury. 2003. Regulatory functions of CD8+CD28– T cells in an autoimmune disease model. J. Clin. Invest. 112: 1037-1048. [Medline]
  16. Chang, C. C., R. Ciubotariu, J. S. Manavalan, J. Yuan, A. I. Colovai, F. Piazza, S. Lederman, M. Colonna, R. Cortesini, R. Dalla-Favera, N. Suciu-Foca. 2002. Tolerization of dendritic cells by TS cells: the crucial role of inhibitory receptors ILT3 and ILT4. Nat. Immunol. 3: 237-243. [Medline]
  17. Rihs, S., C. Walker, J. C. Virchow, Jr, C. Boer, C. Kroegel, S. N. Giri, R. K. Braun. 1996. Differential expression of {alpha}Ebeta7 integrins on bronchoalveolar lavage T lymphocyte subsets: regulation by {alpha}4beta1-integrin crosslinking and TGF-beta. Am. J. Respir. Cell Mol. Biol. 15: 600-610. [Abstract]
  18. Sarnacki, S., B. Begue, H. Buc, F. Le Deist, N. Cerf-Bensussan. 1992. Enhancement of CD3-induced activation of human intestinal intraepithelial lymphocytes by stimulation of the beta7-containing integrin defined by HML-1 monoclonal antibody. Eur. J. Immunol. 22: 2887-2892. [Medline]
  19. Pauls, K., M. Schon, R. C. Kubitza, B. Homey, A. Wiesenborn, P. Lehmann, T. Ruzicka, C. M. Parker, M. P. Schon. 2001. Role of integrin {alpha}E(CD103)beta7 for tissue-specific epidermal localization of CD8+ T lymphocytes. J. Invest. Dermatol. 117: 569-575. [Medline]
  20. Karecla, P. I., S. J. Bowden, S. J. Green, P. J. Kilshaw. 1995. Recognition of E-cadherin on epithelial cells by the mucosal T cell integrin {alpha}M290beta7 ({alpha}Ebeta7). Eur. J. Immunol. 25: 852-856. [Medline]
  21. Cepek, K. L., S. K. Shaw, C. M. Parker, G. J. Russell, J. S. Morrow, D. L. Rimm, M. B. Brenner. 1994. Adhesion between epithelial cells and T lymphocytes mediated by E-cadherin and the {alpha}Ebeta7 integrin. Nature 372: 190-193. [Medline]
  22. Hadley, G. A., E. A. Rostapshova, D. M. Gomolka, B. M. Taylor, S. T. Bartlett, C. I. Drachenberg, M. R. Weir. 1999. Regulation of the epithelial cell-specific integrin, CD103, by human CD8+ cytolytic T lymphocytes. Transplantation 67: 1418-1425. [Medline]
  23. Feng, Y., D. H. Wang, R. W. Yuan, C. M. Parker, D. L. Farber, G. A. Hadley. 2002. CD103 expression is required for destruction of pancreatic islet allografts by CD8+ T cells. J. Exp. Med. 196: 877-886. [Abstract/Free Full Text]
  24. Hori, S., T. Nomura, S. Sakaguchi. 2003. Control of regulatory T cell development by the transcription factor Foxp3. Science 299: 1057-1061. [Abstract/Free Full Text]
  25. Banz, A., A. Peixoto, C. Pontoux, C. Cordier, B. Rocha, M. Papiernik. 2003. A unique subpopulation of CD4+ regulatory T cells controls wasting disease, IL-10 secretion and T cell homeostasis. Eur. J. Immunol. 33: 2419-2428. [Medline]
  26. Lehmann, J., J. Huehn, M. de la Rosa, F. Maszyna, U. Kretschmer, V. Krenn, M. Brunner, A. Scheffold, A. Hamann. 2002. Expression of the integrin {alpha}Ebeta7 identifies unique subsets of CD25+ as well as CD25– regulatory T cells. Proc. Natl. Acad. Sci. USA 99: 13031-13036. [Abstract/Free Full Text]
  27. He, X., C. A. Janeway, Jr, M. Levine, E. Robinson, P. Preston-Hurlburt, C. Viret, K. Bottomly. 2002. Dual receptor T cells extend the immune repertoire for foreign antigens. Nat. Immunol. 3: 127-134. [Medline]
  28. Schelonka, R. L., F. M. Raaphorst, D. Infante, E. Kraig, J. M. Teale, A. J. Infante. 1998. T cell receptor repertoire diversity and clonal expansion in human neonates. Pediatr. Res. 43: 396-402. [Medline]
  29. Maslanka, K., T. Piatek, J. Gorski, M. Yassai, J. Gorski. 1995. Molecular analysis of T cell repertoires: spectratypes generated by multiplex polymerase chain reaction and evaluated by radioactivity or fluorescence. Hum. Immunol. 44: 28-34. [Medline]
  30. Zeijlemaker, W. P., M. H. Van Oers, V. P. Eijsvoogel. 1976. Human lymphocyte subpopulations involved in MLC and CML. Scand. J. Immunol. (Suppl. 5): 143-156.
  31. Hadley, G. A., S. T. Bartlett, C. S. Via, E. A. Rostapshova, S. Moainie. 1997. The epithelial cell-specific integrin, CD103 ({alpha}E integrin), defines a novel subset of alloreactive CD8+ CTL. J. Immunol. 159: 3748-3756. [Abstract]
  32. Nikolaeva, N., E. Uss, E. M. van Leeuwen, R. A. van Lier, I. J. ten Berge. 2004. Differentiation of human alloreactive CD4+ and CD8+ T cells in vitro. Transplantation 78: 815-824. [Medline]
  33. Wever, P. C., J. G. Boonstra, J. C. Laterveer, C. E. Hack, F. J. van der Woude, M. R. Daha, I. J. Berge. 1998. Mechanisms of lymphocyte-mediated cytotoxicity in acute renal allograft rejection. Transplantation 66: 259-264. [Medline]
  34. Rowshani, A. T., S. Florquin, F. Bemelman, J. A. Kummer, C. E. Hack, I. J. ten Berge. 2004. Hyperexpression of the granzyme B inhibitor PI-9 in human renal allografts: a potential mechanism for stable renal function in patients with subclinical rejection. Kidney Int. 66: 1417-1422. [Medline]
  35. Schieferdecker, H. L., R. Ullrich, A. N. Weiss-Breckwoldt, R. Schwarting, H. Stein, E. O. Riecken, M. Zeitz. 1990. The HML-1 antigen of intestinal lymphocytes is an activation antigen. J. Immunol. 144: 2541-2549. [Abstract]
  36. Woodberry, T., T. J. Suscovich, L. M. Henry, M. August, M. T. Waring, A. Kaur, C. Hess, J. L. Kutok, J. C. Aster, F. Wang, et al 2005. {alpha}Ebeta7 (CD103) expression identifies a highly active, tonsil-resident effector-memory CTL population. J. Immunol. 175: 4355-4362. [Abstract/Free Full Text]
  37. Myers, L., M. Croft, B. S. Kwon, R. S. Mittler, A. T. Vella. 2005. Peptide-specific CD8 T regulatory cells use IFN-{gamma} to elaborate TGF-beta-based suppression. J. Immunol. 174: 7625-7632. [Abstract/Free Full Text]
  38. Yuan, R., R. El Asady, K. Liu, D. Wang, C. B. Drachenberg, G. A. Hadley. 2005. Critical role for CD103+CD8+ effectors in promoting tubular injury following allogeneic renal transplantation. J. Immunol. 175: 2868-2879. [Abstract/Free Full Text]
  39. Leteurtre, E., M. C. Copin, M. Labalette, C. Noel, D. Roumilhac, F. R. Pruvot, M. Lecomte-Houcke, B. Gosselin, J. P. Dessaint. 2000. Negative immunohistochemical detection of CD103 ({alpha}Ebeta7 integrin) in the infiltrates of acute rejection in liver and kidney transplantation. Transplantation 70: 227-229. [Medline]
  40. Hadley, G. A., C. Charandee, M. R. Weir, D. Wang, S. T. Bartlett, C. B. Drachenbere. 2001. CD103+CTL accumulate within the graft epithelium during clinical renal allograft rejection. Transplantation 72: 1548-1555. [Medline]
  41. Waaga, A. M., M. Gasser, I. Laskowski, N. L. Tilney. 2000. Mechanisms of chronic rejection. Curr. Opin. Immunol. 12: 517-521. [Medline]
  42. Wang, D., R. Yuan, Y. Feng, R. El-Asady, D. L. Farber, R. E. Gress, P. J. Lucas, G. A. Hadley. 2004. Regulation of CD103 expression by CD8+ T cells responding to renal allografts. J. Immunol. 172: 214-221. [Abstract/Free Full Text]
  43. Teraki, Y., T. Shiohara. 2002. Preferential expression of {alpha}Ebeta7 integrin (CD103) on CD8+ T cells in the psoriatic epidermis: regulation by interleukins 4 and 12 and transforming growth factor-beta. Br. J. Dermatol. 147: 1118-1126. [Medline]
  44. Seder, R. A., T. Marth, M. C. Sieve, W. Strober, J. J. Letterio, A. B. Roberts, B. Kelsall. 1998. Factors involved in the differentiation of TGF-beta-producing cells from naive CD4+ T cells: IL-4 and IFN-{gamma} have opposing effects, while TGF-beta positively regulates its own production. J. Immunol. 160: 5719-5728. [Abstract/Free Full Text]
  45. Li, J., I. Goldstein, E. Glickman-Nir, H. Jiang, L. Chess. 2001. Induction of TCR Vbeta-specific CD8+ CTLs by TCR Vbeta-derived peptides bound to HLA-E. J. Immunol. 167: 3800-3808. [Abstract/Free Full Text]
  46. Goronzy, J. J., C. Xie, W. Hu, S. K. Lundy, C. M. Weyand. 1993. Restrictions in the repertoire of allospecific T cells: contribution of the {alpha}-helical sequence polymorphism of HLA-DR molecules. J. Immunol. 151: 825-836. [Abstract]
  47. Gilliet, M., Y. J. Liu. 2002. Generation of human CD8 T regulatory cells by CD40 ligand-activated plasmacytoid dendritic cells. J. Exp. Med. 195: 695-704. [Abstract/Free Full Text]
  48. Malipiero, U., K. Frei, K. S. Spanaus, C. Agresti, H. Lassmann, M. Hahne, J. Tschopp, H. P. Eugster, A. Fontana. 1997. Myelin oligodendrocyte glycoprotein-induced autoimmune encephalomyelitis is chronic/relapsing in perforin knockout mice, but monophasic in Fas- and Fas ligand-deficient lpr and gld mice. Eur. J. Immunol. 27: 3151-3160. [Medline]
  49. Grossman, W. J., J. W. Verbsky, B. L. Tollefsen, C. Kemper, J. P. Atkinson, T. J. Ley. 2004. Differential expression of granzymes A and B in human cytotoxic lymphocyte subsets and T regulatory cells. Blood 104: 2840-2848. [Abstract/Free Full Text]
  50. Grossman, W. J., J. W. Verbsky, W. Barchet, M. Colonna, J. P. Atkinson, T. J. Ley. 2004. Human T regulatory cells can use the perforin pathway to cause autologous target cell death. Immunity 21: 589-601. [Medline]
  51. Gondek, D. C., L. F. Lu, S. A. Quezada, S. Sakaguchi, R. J. Noelle. 2005. Cutting edge: contact-mediated suppression by CD4+CD25+ regulatory cells involves a granzyme B-dependent, perforin-independent mechanism. J. Immunol. 174: 1783-1786. [Abstract/Free Full Text]



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