HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wolfe, T. Articles by von Herrath, M. G. Search for Related Content PubMed PubMed Citation Articles by Wolfe, T. Articles by von Herrath, M. G.

Reduction of Antiviral CD8 Lymphocytes In Vivo with Dendritic Cells Expressing Fas Ligand—Increased Survival of Viral (Lymphocytic Choriomeningitis Virus) Central Nervous System Infection¹

Tom Wolfe^*, Chrystelle Asseman^*, Anna Hughes^*, Hiroyuki Matsue, Akira Takashima and Matthias G. von Herrath^2,*

^* Division of Immune Regulation La Jolla Institute for Allergy and Immunology 10355 Science Center Drive San Diego, CA 92121; and Department of Dermatology University of Texas Southwestern Medical Center, Dallas, TX 75235

	Abstract

Top Abstract Introduction Materials and Methods Results Discussion References

 
In vivo administration of APC expressing Fas ligand (Fas-L⁺ dendritic cells (DCs)) has shown promise in dampening allergic reactions and transplant rejection. Since the effect in these studies was mainly on CD4 lymphocytes, our goal was to evaluate the ability of such killer DCs to eliminate antiviral CD8 lymphocytes and in this way ameliorate viral immunopathology or, conversely, impede viral clearance. Intravenous administration of Fas-L⁺ DCs resulted in a 50% reduction of lytic CD8 precursors following intracerebral infection with lymphocytic choriomeningitis virus (LCMV), and accordingly, immunopathology and survival of LCMV meningitis were improved, whereas viral clearance remained unaffected. In transfer studies the effect of the Fas-L⁺ DCs was only quantifiable on experienced, not naive, CD8 lymphocytes. Importantly, loading of Fas-L⁺ DCs with viral Ag before therapy was not necessary to achieve this effect, indicating that non-LCMV-infected Fas-L⁺ DCs acquired viral Ag during acute LCMV infection in vivo. Our studies delineate important aspects for the clinical use of Fas-L⁺ DCs in vivo. One should expect that they acquire viral Ags and suppress antiviral CD8 responses to some degree when given while an acute infection is ongoing. In terms of safety it is encouraging that resolution of the infection, at least in the case of LCMV, is not inhibited.

	Introduction

Top Abstract Introduction Materials and Methods Results Discussion References

 
The selective elimination of Ag-specific lymphocytes has long been a quest in immunotherapy directed to ameliorate autoimmunity or virally induced immunopathology. The interaction between professional APCs such as dendritic cells (DCs)³ and T lymphocytes appears a suitable target, and indeed, encouraging observations have been made with compounds that induce tolerance by avoiding or blocking costimulation during cellular activation (1, 2, 3, 4). Using a different strategy, so-called killer DCs have been developed based on the hypothesis that Fas ligand (Fas-L; CD95-L) on DCs would induce apoptosis of interacting Fas-expressing T cells (5, 6, 7, 8, 9, 10). The Fas death pathway is well studied, and Fas-expressing cells die by apoptosis after receiving a signal by interacting with Fas-L (11, 12, 13, 14, 15, 16, 17). To achieve this in an Ag-specific manner, APC and T cell have to also interact by recognizing Ag in context with MHC, and several earlier reports indicate that this is indeed a possibility (7). First, allergic reactions were significantly reduced using in vivo administration of Fas-Ltransduced APC lines. In this system the protection was mostly Ag specific for CD4⁺ lymphocytes reactive to the allergen, as evidenced by lack of suppression of unrelated OVA-specific response (7). Similarly, in follow-up studies naive as well as activated CD4 cells were affected by the Fas-L-expressing DC lines (6, 18). However, to date no information has been obtained with respect to the potential to influence antiviral CD8 responses. This was therefore the focus of our study.

We chose the well-established model of intracerebral (i.c.) infection with lymphocytic choriomeningitis virus (LCMV) (19, 20, 21). Unmanipulated mice all succumb to lethal choriomeningitis within 7 days after LCMV i.c. inoculation. Death is caused by excessive immunopathology due to the antiviral CD8 response and depends on lytic effector function as well as IFN- production. Importantly, mice that are harboring LCMV-specific memory lymphocytes at the time of i.c. infection will survive, because viral spread is limited more rapidly by memory effectors. Conversely, mice without LCMV memory will only survive the more widespread i.c. infection if antiviral immunity is inhibited, for example by depleting CD8 CTL. The potential tradeoff is lack of viral clearance and persistent infection if immunity is lowered beyond a certain threshold. Persistent LCMV infection of the brain, however, will cause no major clinical problems, since LCMV is a non-lytic virus. Along this line of evidence, we reasoned that eliminating a certain amount of anti-LCMV CD8 lymphocytes would be beneficial and result in enhanced survival without significantly affecting viral clearance. The use of Fas-L⁺ DCs appeared an ideal tool for this task. We used the Fas-L stable-transduced DCs that had been effective in earlier studies (7). Our findings show that survival can be enhanced, which is associated with a 50% reduction of activated, antiviral CD8 lymphocytes. Importantly, viral clearance is not impeded. The effect is not dependent on the expression of LCMV viral Ags by Fas-L⁺ DCs before in vivo administration, probably because viral Ag is acquired by a significant number of such DCs during acute infection. Thus, immunotherapy with Fas-L⁺ DCs appears a clinical possibility that is "gentle" enough to leave the host sufficiently immune-competent to combat viral infections.

	Materials and Methods

Top Abstract Introduction Materials and Methods Results Discussion References

 
Virus, mouse lines, and i.c. LCMV infection model

The strain of LCMV used in all studies was strain Armstrong. LCMV was grown, purified, and titrated as described by us previously (21). For i.c. infection, LCMV was diluted immediately before injection of 1000 PFU in a maximal volume in 50 µl PBS (21). The injection depth did never exceed 3 mm, and the detailed method, performed under general anesthesia, has been described previously (21). All mice were (BALB/cByJ x A/J)F₁ offspring to create a congenic environment for the transfer of the Fas-L⁺ DCs and control DC lines derived originally from A/J mice.

Maintenance and in vivo administration of DC lines

The DC line XS106 that was originally generated from the epidermis of newborn A/J mice was transfected with CD95-L plasmid DNA (pMKIT-B6/CD95L) or with the neomycin resistance gene alone. Stable transfected Fas-L⁺ DC and control DC clones were then established by selection with G418, followed by limiting dilution (7). Both lines were maintained in the presence of complete RPMI with 10% FBS and G418 at 300 µg/ml, 1 ng/ml of murine GM-CS, and 5% (volume) NS47 fibroblast-conditioned medium (7). Cells were washed three times and resuspended at the appropriate concentration in PBS before injection into mice.

Lytic CD8 T cell assays

CTL activity was measured in a standard 5- to 6-h in vitro ⁵¹Cr release assay as previously described (22). In brief, BALB/Cl7, H-2^d target cells were infected with LCMV (multiplicity of infection, 1) or coated with MHC I-restricted LCMV peptides (RPQASGVYM; 10^-5 M). Assays using splenic lymphocytes ex vivo employed E:T cell ratios of 50:1, 25:1, and 12.5:1, while those using secondary (memory) CTL after 5-day in vitro stimulation with irradiated syngeneic LCMV-infected peritoneal exudate cells used ratios of 5:1 and 2.5:1. Lytic units were calculated by correlating lysis found at different E:T cell ratios from several experiments and defining the number of effector cells required for the respective lysis of one target cell (23). For precursor frequency analysis (21), spleen cells were serially diluted and cultured in 96-well, flat-bottom plates in the presence of T cell growth factor (primarily containing IL-2), irradiated LCMV-infected peritoneal exudate cells, and spleen feeder cells. After 8–10 days, cultures were assayed for CTL activity on LCMV-infected and uninfected target cells. Precursor frequencies were calculated as previously described (22).

Intracellular cytokine and other FACS analyses

For surface stains, single-cell suspensions prepared from lymphatic organs were treated with FcBlock (BD PharMingen, San Diego, CA) to block Fc receptors before using the following FITC-, PE-, CyChrome-, PerCP-, or allophycocyanin-conjugated, biotinylated, and/or purified Abs (BD PharMingen, unless noted otherwise): CD4, CD8, CD95, CD95L, CD40, CD80, CD86, MHCI, CD11b, CD11c, MHC II, CD54, and TNF-. In some experiments propidium iodide incorporation (5 µg/ml) (22) was used to analytically exclude dead cells. For intracellular stains, single-cell suspensions were restimulated for 5–7 h with 1 µg/ml MHC class I-restricted viral peptides in the presence of 10–50 U/ml of recombinant human IL-2 (BD PharMingen) and 1 µg/ml brefeldin A (Sigma, St. Louis, MO). In some cases polyclonal stimulation was provided by anti-CD3 and anti-CD28 (BD PharMingen). Staining of cell surface Ag and intracellular Ags was performed as previously described (22, 23). Cells were acquired with a FACSort or FACSCalibur flow cytometer (BD Biosciences, San Jose, CA) using CellQuest software (BD Biosciences). For five- and six-color analyses, a FACSVantage SE flow cytometer (BD Biosciences) was used.

In vivo labeling and tracking of lymphocytes

For identification of naive vs LCMV-activated transferred splenocyte populations, cells were labeled in vitro by CFSE as described below. Naive BALB/cByJ x A/J spleens were incubated for 10 min at 37°C with 5 µM CFSE in PBS (5 x 10⁶ cells/ml). In contrast, spleens from LCMV-infected donors were harvested on day 7 and labeled with 0.5 µM CFSE. The reaction was stopped before in vivo transfer (together with DC lines) with 5% FCS (final concentration). FACS analysis was performed using CD4 (FL-3), CD8 (FL-4), and B220 (FL-2) staining as described above, CFSE was detected on FL-1.

	Results

Top Abstract Introduction Materials and Methods Results Discussion References

 
In vivo administration of Fas-L⁺ DCs increases survival of lymphocytic choriomeningitis: acquisition of viral Ag in vivo

Before or after i.c. LCMV infection with 50 PFU (>10 LD₅₀), mice received 5 x 10⁵ Fas-L-transduced killer DCs that were LCMV infected or coated with LCMV CD8 peptides. A syngeneic DC line that was transduced with vector alone was used as a control. The two DC lines expressed similar levels of CD11b, MHC class II, MHC class I, B7.1, B7.2, and CD40 (Table I and Fig. 1). As shown in Fig. 2A, i.v. injection of Fas-L-expressing DCs 2 days before LCMV infection significantly (p = 0.04) improved survival compared with the effect of treatment with non-Fas-L-expressing regular DCs and marginally, but significantly, improved survival compared with that of the untreated control group (p < 0.05). Interestingly, this effect was not at all dependent on the expression of LCMV Ags by the DCs. Whereas untreated mice succumbed to lethal LCMV precisely 7 days after LCMV i.c. infection, 20% of the mice treated with LCMV-infected, peptide-coated, or uninfected Fas-L⁺ DCs survived, and death in at least 40% of the animals occurred 1 day later. These differences are not dramatic, but they are significant in the particular model system that we chose. After i.c. LCMV infection all mice always die within 7 days. Therefore, any survival is noteworthy, and a 20% survival rate is never seen in control groups. In addition, Fas-L-expressing DCs have a clinical effect that is independent of the Ag they were engineered to express in vitro, indicating that they either acquire LCMV Ags in vivo or affect all lymphocytes that express Fas equally. In significant contrast to Fas-L⁺ DCs, treatment with regular DCs accelerated death in all mice by 1 day (Fig. 2A). This was probably due to increased immunopathology caused by increased numbers of DCs system-wide. Importantly, if Fas-L⁺ DCs were given in any of the groups >2–3 days after or >2 days before LCMV i.c. infection, no effect was noted (Fig. 2B). This indicated that Fas-L⁺ DCs had much better efficacy early during the systemic activation of LCMV CTL and that their period of in vivo efficacy was limited. Lastly, viral clearance of LCMV was not affected by the Fas-L⁺ DCs treatment, since the survivors of i.c. infection did not exhibit live virus in their brains (average, 10⁴ PFU/g brain tissue on day 3 postinfection in Fas-L⁺ DC-treated mice; no PFU detectable in survivors day 14 postinfection; PFU assessed by plaque assays) (21).

View larger version (17K): [in this window] [in a new window]   FIGURE 1. Similar phenotypic features of Fas-L+ and control DC lines. The Fas-L+ and control DC lines were generated and propagated as described in Materials and Methods. Surface molecule levels were assessed by FACS analysis (see Materials and Methods). Note that both lines express similar levels of MHC molecules and costimulators, indicating that the differential in vivo effects we observed are not due to altered immunological properties other than the expression of CD95L (Fas-L).

View larger version (27K): [in this window] [in a new window]   FIGURE 2. A, Increased survival of (BALB/cByJ x A/J)F1 mice infected i.c. with LCMV and treated with Fas-L+ DCs or regular (control) DCs. Groups of 10 (A/J x BALB/cByJ)F1 mice received 2 x 106 DCs i.v. on day -2 before i.c. LCMV infection with 50 PFU in 50 ml PBS. As expected and observed in many investigations by different laboratories previously (21 ), mice that had not received any DCs all died 7 days later. Controls injected with PBS alone all survived (not shown). Injection of 2 x 106 regular DCs consistently accelerated death by 1 day. In contrast, Fas-L+ DCs (2 x 106) prolonged survival in >40% of the mice, and one-fifth did not succumb to LCMV at all. The difference between Fas-L- and non-Fas-L-expressing DC-treated groups is significant (p = 0.04, by log-rank survival analysis). If Fas-L+ DCs were given >3 days after i.c. LCMV infection or more frequently, no enhancement of survival was observed (not shown). The overall study was repeated once with comparable results, and LCMV infection (multiplicity of infection, 1:1; 48 h in vitro) was replaced by a 4-h coating step with LCMV CD8 peptide NP118 (RPQASGYMG). The experimental outcome was similar regardless of which Ag source was used (peptide or virus) in that improvement of survival only correlated with Fas-L, but not Ag, expression by DC lines. The preparation and maintenance of DC lines are described in Materials and Methods and previously (7 ). B, Fas-L+ DCs are only effective in enhancing survival of i.c. LCMV infection when given immediately prior to or concomitantly with the viral inoculation. The inoculation of mice, DC administration, and other experimental details were identical with those described in A, except that the Fas-L+ DCs were given either i.v. or i.p. at different time points in relation to LCMV i.c. infection. Note that in none of the experiments was there any survival in those groups of mice injected with no DCs or control DCs. In these groups death occurred on day 7 or earlier in all mice, as shown in A. A total of >20 control mice were used in all groups combined, which makes the observed survival in the groups receiving Fas-L+ DCs on day -2 or 0 significant.

We wanted to further examine the issue of how Fas-L⁺ DC treatment affected LCMV-specific and overall CD8 cell effector functions. Lytic precursors (1, 21, 24) and lytic units (25) of CD8 CTL were determined 7 days after i.c. LCMV infection. Both assessments constitute a precise measurement of LCMV-specific CTL activity, whereby lytic units are better reflective of systemically activated CTL and pCTL measure precursors destined or capable of becoming effector CTL. In correlation with the enhanced survival following Fas-L⁺ DCs treatment, lytic CTL and precursors were reduced by a factor of 2 (p < 0.05, by paired t test; Table II). This decrease was observed independently of LCMV infection of Fas-L⁺ DCs before injection into recipients, which indicates that the effect on systemic CTL and survival is not specific for the initial Ag expressed by the Fas-L⁺ DCs and implies that any injected DC (including the Fas-L⁺ DCs) will acquire LCMV Ags during acute viral infection in vivo. Interestingly, there was no quantifiable effect on overall CD8 lymphocyte numbers capable of producing IFN- after CD3/CD28 activation, which demonstrates that the Fas-L⁺ DCs act Ag-specifically on the LCMV population and do not eliminate overall CD8 lymphocytes. In accordance with this finding, the absolute numbers of CD8 cells in spleens comparing Fas-L⁺ and control DC treated mice at 7 days after i.c. LCMV infection were similar (1.2 x 10⁷ ± 15 vs 1.35 x 10⁷ ± 12%). This observation also indicates that the Fas-L⁺ DCs do not affect overall CD8 cell expansion significantly.

To better understand which cell types were affected in vivo following Fas-L⁺ DC administration, we hypothesized that the Fas-L-transduced DCs had to act on recently activated, LCMV-specific lymphocytes. Since overall numbers of naive or Ag-specific lymphocytes are difficult to directly quantitate ex vivo, we chose to use a transfer system in which naive splenocytes are labeled with high amounts of CFSE dye, and LCMV-activated splenocytes (day 7 postinfection) are labeled with low amounts of CFSE before transfer into syngeneic recipients. At the same time, Fas-L⁺ or regular DC lines were given (both infected with LCMV), and CD4, CD8, and B lymphocytes labeled with low or high amounts of CFSE were quantitated 20 h later by FACS. As shown in Fig. 2 and Table III, the only cell type that was significantly (p < 0.05) affected by Fas-L⁺ DC administration was activated CD8 lymphocytes (day 7 LCMV infection), and an 50% reduction was observed relative to overall CD8 numbers. Naive CD4, CD8, or B cells or LCMV-activated (day 7) CD4 or B-lymphocytes were not decreased or increased in number (Table III). Importantly, this reduction of activated CD8 cells was not observed when lymphocytes had been activated with an irrelevant vaccinia virus before adaptive transfer (not shown) (21). Thus, the Fas-L⁺ DC treatment acted Ag specifically in vivo.

	Discussion

Top Abstract Introduction Materials and Methods Results Discussion References

View larger version (47K): [in this window] [in a new window]   FIGURE 3. Fas-L-expressing DCs affect LCMV-activated lymphocytes. FACS analysis is shown for two representative (A/J x BALB/cByJ)F1 mice that were irradiated with a low dose (300 rad) and received transfer of naive (CFSEhigh) and LCMV-activated (CFSElow) splenocytes (2 x 106 cells i.p., respectively). Before transfer, labeling with CFSE was performed for 10 min in vitro on either naive (CFSEhigh) or LCMV-activated (day 7 postinfection, CFSElow) splenocytes (see Materials and Methods). At the same time, recipient mice received an injection of either 2 x 106 control or Fas-L+ DCs i.v. After 20 h the numbers of naive (CFSEhigh) or LCMV-activated (CFSElow) lymphocytes in spleens were assessed by FACS analysis, and comparisons between groups were made. Overall data from all experiments including statistical analysis are shown in Table III. The percentages given in the figure are: R2, percentage of naive CD8 lymphocytes of overall gated splenocytes; R3, percentage of LCMV day CD8 lymphocytes of overall gated splenocytes; and R4, percentage of overall CD8 lymphocytes of overall gated splenocytes.

Overall numbers of CD8 cells in spleens of control and Fas-L⁺ DC-treated mice were comparable. These findings strengthen the argument that there really is a reduction of LCMV-specific CD8 precursors and lytic CTL in the Fas-L⁺ DC-treated group (Table II); they do not show, however, whether this is due to a lack of expansion or elimination of CTL. We believe, based on the data presented in Table III (mapping the Fas-L⁺ DC effect to LCMV-activated effectors and not naive lymphocytes) and Fig. 2B (demonstrating that DCs have to be given early), that the Fas-L⁺ DC effect is due to an early elimination of some LCMV-specific activated, but not naive, lymphocytes. This results consequently in a 2-fold lower number of LCMV effectors at 7 days postinfection and a reduction of immunopathology in 20% of the mice. It is very clear from data shown in Fig. 2B that the Fas-L⁺ DCs have no prolonged in vivo effect, since the window of therapeutic opportunity abruptly closes 3 days after LCMV infection. Based on this observation, one can argue that only in the very early stages of CTL activation will the elimination of some LCMV-specific lymphocytes have an effect that becomes clinically visible in 20% of the mice. Additionally, the biological activity of Fas-L⁺ DCs in vivo is rather short-lived (maximally 4 days for their majority), because pretreatment of mice with APCs 4 days before infection did not result in any protection (Fig. 2B). Thus, strategies to enhance the in vivo efficacy of Fas-L⁺ DCs could be of value in the future.

An interesting question is where do the Fas-L-transfected DC lines exert their effect in vivo? We know that they can act systemically, affecting transferred, LCMV-activated CD8 lymphocytes (Table III and Fig. 3) and therefore are unlikely to just operate at the site of i.c. infection. Quantitatively, they lose their potential several days after injection (Fig. 2B), which indicates that no long term effects on the immune system should be expected. To use short-lived APCs in vivo might be important, because one has to realize that Ag specificity cannot necessarily be maintained in vivo in the presence of an ongoing systemic viral infection when injecting Fas-L-transduced DCs. This is true even if the Fas-L⁺ DCs were matured in vitro and express predominantly the desired Ag, as was the case for the Fas-L-transfected DC lines used in our study once they were infected with LCMV in vitro. Our study provides an important example for a scenario where a replicating agent such as LCMV is present in vivo. In this situation, one can assume that the probability that the transferred DC cell lines will become infected in vivo is high, and therefore control of the precise Ag specificity will be difficult to maintain. The positive aspect of these observations is that the effect of Fas-L⁺ DCs on antiviral responses in vivo is limited (Table II), and as a consequence, viral clearance is not impaired, although immunopathology can be improved (Fig. 2). Therefore, safety concerns are minimal if such DC lines were to be used in vivo to lower certain allergen-specific or autoimmune responses, because they would be unlikely to have a profound effect on resolution of a simultaneously occurring virus infection even if they became infected in vivo.

Thus, in conclusion, engineered Fas-L-expressing DC lines are likely to have minor effects on antiviral systemic responses. This is probably of value if such cells are used to target other Ag-specific responses, for example in allergy or autoimmunity. From our present data it seems that their early, prophylactic use might be more efficacious than their administration after an immune response has already been fully activated. In this respect we were able to improve viral immunopathology without affecting viral clearance, which opens up a novel therapeutic avenue for Fas-L⁺ DCs. The dampening antiviral responses in vivo might be of value in certain clinical situations where immunity to the virus is more harmful than the virus itself.

	Acknowledgments

 
We thank Diana Frye for assistance with the manuscript preparation.

	Footnotes

 
¹ This work was supported by Grants DK51091 and U-19AI51973 (to M.G.v.H.). This is Publication 505 from the La Jolla Institute for Allergy and Immunology.

² Address correspondence and reprint requests to Dr. Matthias G. von Herrath, Division of Immune Regulation, La Jolla Institute for Allergy and Immunology, 10355 Science Center Drive, San Diego, CA 92121. E-mail address: matthias{at}liai.org

³ Abbreviations used in this paper: DC, dendritic cell; Fas-L, Fas ligand; i.c., intracerebral; LCMV, lymphocytic choriomeningitis virus.

Received for publication June 24, 2002. Accepted for publication August 19, 2002.

	References

Top Abstract Introduction Materials and Methods Results Discussion References

 

1. Homann, D., A. Jahreis, T. Wolfe, A. Hughes, B. Coon, M. J. van Stipdonk, K. R. Prilliman, S. P. Schoenberger, M. G. von Herrath. 2002. CD40L blockade prevents autoimmune diabetes by induction of bitypic NK/DC regulatory cells. Immunity 16:403.[Medline]
2. Tamada, K., H. Tamura, D. Flies, Y. X. Fu, E. Celis, L. R. Pease, B. R. Blazar, L. Chen. 2002. Blockade of LIGHT/LT and CD40 signaling induces allospecific T cell anergy, preventing graft-versus-host disease. J. Clin. Invest. 109:549.[Medline]
3. Rossini, A. A., J. P. Mordes, D. L. Greiner, J. S. Stoff. 2001. Islet cell transplantation tolerance. Transplantation 72:S43.[Medline]
4. Hanninen, A., N. R. Martinez, G. M. Davey, W. R. Heath, L. C. Harrison. 2002. Transient blockade of CD40 ligand dissociates pathogenic from protective mucosal immunity. J. Clin. Invest. 109:261.[Medline]
5. Hammond, K. J., D. G. Pellicci, L. D. Poulton, O. V. Naidenko, A. A. Scalzo, A. G. Baxter, D. I. Godfrey. 2001. CD1d-restricted NKT cells: an interstrain comparison. J. Immunol. 167:1164.[Abstract/Free Full Text]
6. Kusuhara, M., K. Matsue, D. Edelbaum, J. Loftus, A. Takashima, H. Matsue. 2002. Killing of naive T cells by CD95L-transfected dendritic cells (DC): in vivo study using killer DC-DC hybrids and CD4⁺ T cells from DO11.10 mice. Eur. J. Immunol. 32:1035.[Medline]
7. Matsue, H., K. Matsue, M. Walters, K. Okumura, H. Yagita, A. Takashima. 1999. Induction of antigen-specific immunosuppression by CD95L cDNA-transfected "killer" dendritic cells. Nat. Med. 5:930.[Medline]
8. Min, W. P., R. Gorczynski, X. Y. Huang, M. Kushida, P. Kim, M. Obataki, J. Lei, R. M. Suri, M. S. Cattral. 2000. Dendritic cells genetically engineered to express Fas ligand induce donor-specific hyporesponsiveness and prolong allograft survival. J. Immunol. 164:161.[Abstract/Free Full Text]
9. Zhang, H.-G., X. Su, D. Liu, W. Liu, P. Yang, Z. Wang, C. K. Edwards, H. Bluethmann, J. D. Mountz, T. Zhou. 1999. Induction of specific T cell tolerance by Fas ligand-expressing antigen-presenting cells. J. Immunol. 162:1423.[Abstract/Free Full Text]
10. Zhang, H. G., M. Fleck, E. R. Kern, D. Liu, Y. Wang, H. C. Hsu, P. Yang, Z. Wang, D. T. Curiel, T. Zhou, et al 2000. Antigen presenting cells expressing Fas ligand down-modulate chronic inflammatory disease in Fas ligand-deficient mice. J. Clin. Invest. 105:813.[Medline]
11. Van Parijs, L., A. K. Abbas. 1996. Role of Fas-mediated cell death in the regulation of immune responses. Curr. Opin. Immunol. 8:355.[Medline]
12. Van Parijs, L., A. Ibraghimov, A. K. Abbas. 1996. The roles of costimulation and Fas in T cell apoptosis and peripheral tolerance. Immunity 4:321.[Medline]
13. Kishimoto, H., J. Sprent. 1999. Strong TCR ligation without costimulation causes rapid onset of Fas-dependent apoptosis of naive murine CD4⁺ T cells. J. Immunol. 163:1817.[Abstract/Free Full Text]
14. Green, D. R., T. A. Ferguson. 2001. The role of Fas ligand in immune privilege. Nat. Rev. Mol. Cell. Biol. 2:917.[Medline]
15. Zimmermann, K. C., D. R. Green. 2001. How cells die: apoptosis pathways. J. Allergy Clin. Immunol. 108:S99.[Medline]
16. Refaeli, Y., L. Van Parijs, C. A. London, J. Tschopp, A. K. Abbas. 1998. Biochemical mechanisms of IL-2-regulated fas-mediated T cell apoptosis. Immunity 8:615.[Medline]
17. Griffith, T. S., T. Brunner, S. M. Fletcher, D. R. Green, T. A. Ferguson. 1995. Fas ligand-induced apoptosis as mechanism of immune privilege. Science 270:1189.[Abstract/Free Full Text]
18. Matsue, H., K. Matsue, M. Kusuhara, T. Kumamoto, K. Okumura, H. Yagita, A. Takashima. 2001. Immunosuppressive properties of CD95L-transduced "killer" hybrids created by fusing donor- and recipient-derived dendritic cells. Blood 98:3465.[Abstract/Free Full Text]
19. Buchmeier, M., R. Welsh, F. Dutko, M. B. A. Oldstone. 1980. The virology and immunobiology of LCMV infection. Adv. Immunol. 30:275.[Medline]
20. Nansen, A., O. Marker, C. Bartholdy, A. R. Thomsen. 2000. CCR2⁺ and CCR5⁺ CD8⁺ T cells increase during viral infection and migrate to sites of infection. Eur. J. Immunol. 30:1797.[Medline]
21. von Herrath, M. G., M. Yokoyama, J. Dockter, M. B. Oldstone, J. L. Whitton. 1996. CD4-deficient mice have reduced levels of memory cytotoxic T lymphocytes after immunization and show diminished resistance to subsequent virus challenge. J. Virol. 70:1072.[Abstract]
22. von Herrath, M. G., S. Guerder, H. Lewicki, R.A. Flavell, M. B. A. Oldstone. 1995. Coexpression of B7-1 and viral ("self") transgenes in pancreatic cells can break peripheral ignorance and lead to spontaneous autoimmune diabetes. Immunity 3:727.[Medline]
23. von Herrath, M.G., J. Dockter, M. Nerenberg, J.E. Garin, M.B.A. Oldstone. 1994. Thumic selection and adaptability of cytotoxic T lymphocyte responses in transgenic mice expressing a viral protein in the thymus. J. Exp. Med. 180:1901.[Abstract/Free Full Text]
24. von Herrath, M. G., S. Guerder, H. Lewicki, R. A. Flavell, M. B. Oldstone. 1995. Coexpression of B7-1 and viral ("self") transgenes in pancreatic beta cells can break peripheral ignorance and lead to spontaneous autoimmune diabetes. Immunity 3:727.
25. von Herrath, M. G., J. Dockter, M. Nerenberg, J. E. Gairin, M. B. Oldstone. 1994. Thymic selection and adaptability of cytotoxic T lymphocyte responses in transgenic mice expressing a viral protein in the thymus. J. Exp. Med. 180:1901.
26. Suss, G., K. Shortman. 1996. A subclass of dendritic cells kills CD4 T cells via Fas/Fas-ligand-induced apoptosis. J. Exp. Med. 183:1789.[Abstract/Free Full Text]
27. Homann, D., A. Holz, A. Bot, B. Coon, T. Wolfe, J. Petersen, T. P. Dyrberg, M. J. Grusby, M. G. von Herrath. 1999. Autoreactive CD4⁺ T cells protect from autoimmune diabetes via bystander suppression using the IL-4/Stat6 pathway. Immunity 11:463.[Medline]

This article has been cited by other articles:

				C. Schutz, M. Fleck, A. Mackensen, A. Zoso, D. Halbritter, J. P. Schneck, and M. Oelke Killer artificial antigen-presenting cells: a novel strategy to delete specific T cells Blood, April 1, 2008; 111(7): 3546 - 3552. [Abstract] [Full Text] [PDF]

				S. Hoves, S. W. Krause, D. Halbritter, H.-G. Zhang, J. D. Mountz, J. Scholmerich, and M. Fleck Mature But Not Immature Fas Ligand (CD95L)-Transduced Human Monocyte-Derived Dendritic Cells Are Protected from Fas-Mediated Apoptosis and Can Be Used as Killer APC J. Immunol., June 1, 2003; 170(11): 5406 - 5413. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Permissions Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wolfe, T. Articles by von Herrath, M. G. Search for Related Content PubMed PubMed Citation Articles by Wolfe, T. Articles by von Herrath, M. G.