| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
*
Immunogenetics and Transplantation Laboratory, Department of Surgery, University of California, San Francisco, CA 94114; and
Nephrology Division, Department of Medicine, Cleveland Veterans Affairs Medical Center, and Institute of Pathology, Case Western Reserve University, Cleveland, OH 44106
 |
Abstract |
|---|
 Top Abstract IntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
|
Introduction |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
There is accumulating evidence, however, that indirect alloreactivity represents an essential component of the allograft rejection process. Indirect alloresponses can provide T cell help for induction of alloreactive cytotoxic lymphocytes (5, 6) and the production of anti-graft Abs by B cells (7) and thereby may play a key role in the effector phase of the graft rejection itself. In support of this latter point, recent studies in reconstituted immunodeficient mice have demonstrated that anti-donor MHC peptide-specific T cells, in the absence of a direct pathway alloresponse, are sufficient to ensure the rejection of allotransplanted tissues (8, 9). Despite this, the relative contributions of the direct and indirect pathways to the naturally developing rejection process in immunocompetent recipients are not known. A thorough understanding of this issue will be crucial to the design of new immune-based strategies to achieve transplantation tolerance.
The characterization of T cells responding to Ags presented via the indirect allorecognition pathway has been limited by a technical inability to readily measure low frequency immune responses in vivo. An improved methodology for monitoring the frequency and cytokine profiles of allospecific T cells involved in both direct and indirect alloresponses would therefore probably provide new insights into the immune physiology of the rejection process. In the present study we used a highly sensitive enzyme-linked immunospot (ELISPOT)3 technique to determine the frequency, specificity, and functional properties of T cells that recognize either intact or processed donor MHC Ags after placement of allogeneic skin grafts. We observed that the vast majority of alloreactive T cells were reactive to Ags presented by the direct pathway of allorecognition and displayed a mixed type 1/type 2 cytokine phenotype. During early allogeneic skin graft rejection T cells responding to donor Ag via the indirect pathway represented approximately 10% of the total number of allospecific T cells. In addition, we observed that while the rejection process was ongoing, the T cell alloresponse was predominantly detected in the draining lymph nodes (LN) of the skin graft. After rejection, however, anamnestic T cell responses to graft Ags were observed almost exclusively in the spleen. Finally, this kinetic analysis demonstrated that the indirect T cell response became progressively more restricted over time. Although it was initially comprised of a polyspecific immune response, indirect alloreactivity later became focused on a single known dominant peptide determinant (ß-chain region 58–71) derived from a single donor molecule, I-Ak. The implications of these findings for understanding the immunological mechanisms underlying allotransplant rejection are discussed.
|
Materials and Methods |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
Female BALB/c (H-2d), B10.A (H-2a), SJL (H-2s), and C57BL/6 (H-2b) mice along with male C57BL/6 (H-2b) mice, 5–8 wk of age, were purchased from The Jackson Laboratory (Bar Harbor, ME) and were maintained in our pathogen-free facility at the Cleveland Veterans Affairs Medical Center (Cleveland, OH).
Peptides
I-Akß58–71 (I-Ap2, AEYWNKQYLERTRA) and hen egg white lysozyme 106–116 (HEL106–116, NAWVAWRNRCK) were synthesized and purified (>90%) by Research Genetics (Huntsville, AL).
Preparation of stimulator cells
Mitomycin C (MMC)-treated splenocytes were used as stimulator cells for all experiments. Single-cell suspension of splenocytes were prepared and treated with MMC (50 µg/ml) in PBS for 20 min at 37°C. The cells were washed three times with HBSS and resuspended in HL-1 medium for all assays. Previous studies revealed that 4–6 x 105 cells/well provided optimal responses (10).
Preparation of donor Ag
As a source of donor Ag for studies of indirect allorecognition, the MMC-treated stimulator cells were suspended at concentrations between 1–40 x 106/ml in HBSS, sonicated with 10 1-s pulses on ice, frozen in a dry ice/ethanol bath, and then thawed at room temperature. Any residual intact cells or cell membranes were removed by centrifugation at 1200 rpm for 10 min at room temperature. Fifty microliters of the resultant supernatant was added to enzyme-linked immunospot wells as indicated.
T cell isolation
T cells were purified from single-cell suspensions of draining LNs or spleen cells using commercially available T cell isolation columns (R & D Systems, Minneapolis, MN) according to the manufacturer’s recommendations. Purified T cells were >95% CD3+ by FACS (not shown).
ELISPOT
ELISPOT plates (Autoimmun Diagnostika, Columbia, MO) were coated
with the capture Ab in sterile PBS overnight. R46A2, produced and
isolated in our laboratory from a hybridoma, was used at 4 µg/ml for
IFN-
. Anti-IL-2 capture Ab (3 µg/ml; Autoimmun Diagnostika) was
used for IL-2, 11B11 produced and isolated in our laboratory from a
hybridoma was used at 2 µg/ml for IL-4, and anti-IL-5 capture Ab
(5 µg/ml; Autoimmun Diagnostika) was used for IL-5. The plates were
then blocked for 1 h with sterile PBS containing 1% BSA and
washed three times with sterile PBS. LN cells, spleen cells, or
purified T cells (5 x 104 to 5 x
105) in 200 µl of HL-1 medium were placed in each well
with or without stimulator cells (4–6 x 105
cells/well) (10), stimulator cell sonicate, or peptide and cultured for
24 h at 37°C in 5% CO2. After washing, biotinylated
anti-lymphokine detection Abs were added overnight.
XMG1.2-horseradish peroxidase (diluted 1/200 from stock produced in our
laboratory from hybridoma) was used for IFN-, rat anti-mouse
IL-2-biotin (2 µg/ml; Autoimmun Diagnostika) was used for IL-2, and
rat anti-mouse IL-4-biotin (2 µg/ml; Autoimmun Diagnostika) and
rat anti-mouse IL-5 (4 µg/ml Autoimmun Diagnostika) were used for
IL-5. Streptavidin-horseradish peroxidase (Dako, Carpinteria, CA;
1/2000 in PBS/0.025% Tween for 2 h at room temperature) was used
as a third reagent for IL-2, and anti-IgG2a-horseradish peroxidase
(Zymed, South San Francisco, CA; 1/300 in PBS/0.025% Tween for 2
h at room temperature) was used as a third reagent for IL-5. The plates
were developed using 800 µl of 3-amino-9-Ethylcarbazole (AEC)
(Pierce, Rockford, IL; 10 mg dissolved in 1 ml of dimethylformamide)
mixed in 24 ml of 0.1 M sodium acetate, pH 5.0, plus 12 µl
H2O2. The resulting spots were counted on a
computer-assisted enzyme-linked immunospot image analyzer (T Spot Image
Analyzer, Autoimmun Diagnostika), which is designed to detect
enzyme-linked immunospots using predetermined criteria.
Skin grafts
Full-thickness trunk skin allografts were placed using standard techniques (11). Skin was harvested from euthanized donor mice, the s.c. fat was removed, and the skin was cut into 0.5-cm pieces and placed in sterile PBS until used for transplantation (<30 min). Recipient mice were anesthetized with pentobarbital (50 mg/kg body weight) and shaved around the chest and abdomen. The skin allograft was placed in a slightly larger graft bed prepared over the chest of the recipient and secured using Vaseline gauze and a bandage. Bandages were removed on day 7, and the grafts were then visually scored daily for evidence of rejection. The allograft was considered fully rejected when it was >90% necrotic. In selected animals, allograft rejection was confirmed histologically.
|
Results |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
A). As the draining LNs
contained BALB/c APCs in addition to responder T cells, the detected
frequencies represented the total alloresponse, including both the
direct and the indirect pathway. The LN cells produced IFN-
(
4000/million LN cells), IL-2 (1900/million LN cells), and IL-4
(600/million LN cells), but no IL-5 was detected (not shown).
Alternatively, the LN cells responded only weakly to fully allogeneic
third-party SJL (H-2s) spleen cells (<50
spots/million for all three cytokines). LN cells from BALB/c recipients
of control syngeneic skin and spleen cells from naive BALB/c mice
produced cytokines at low frequency in response to B10.A stimulator
cells (50–250 spots/million for all cytokines; Fig. 1A).
The detected recall responses to alloantigens were also 10- to 100-fold
higher than recall responses to nominal Ags (i.e., <100 spots/million
T cells after immunization with H-2d-restricted
peptides I-Aßk58–71 (shown below) or
OVA323–339 (13)), thereby reaffirming the polyclonality of
the alloresponse (13, 14, 15). The presence of a detectable IL-4 component
was found consistently in our studies. Although some other
investigators have failed to detect IL-4 in culture supernatants using
standard ELISAs, we recently showed that this lack of detection was due
to uptake of IL-4 by specific receptors expressed on cells in the
culture (10).
|
, IL-2, and IL-4 lymphokines.
IL-5 responses were not significantly higher than background and are
not shown. Representative enzyme-linked immunospot wells for IFN-
production are shown in Fig. 2, and the
spot frequencies for all three cytokines are summarized in Fig. 1
B. Direct alloreactivity was assessed by mixing the
responder T cells with MMC-treated donor B10.A splenocytes. As shown,
this resulted in a response with a cytokine profile similar to the
response using unfractionated LN cells (Fig. 1A), but at
notably higher frequency, consistent with enrichment for T cells.
Essentially no response was detectable to syngeneic stimulators or to
fully allogeneic third-party SJL stimulators (<20 spots/million cells;
Fig. 1B). In additional control experiments, T cells from
naive mice and T cells from mice engrafted with syngeneic BALB/c trunk
skin responded weakly to B10.A stimulator cells (50–150 spots/million;
Fig. 1B).
|
and 3). Optimization of assay parameters is
shown as an inset in Fig. 3. Increasing concentrations of donor
splenocytes were sonicated/freeze-thawed and then added to the ELISPOT
wells containing responder T cells and syngeneic APCs. Detectable spots
reached a plateau after addition of sonicates prepared from 20 x
106 cells/ml for all three cytokines tested. This
concentration of cells was used for preparation of sonicates in all
subsequent experiments. Using this method, the detected frequency of
indirect alloreactivity was about 110 spots/million T cells for
IFN-, 140 spots/million T cells for IL-2, and 10 spots/million T
cells for IL-4, corresponding to approximately 5% of the direct
pathway response (Fig. 3). T cells isolated from control mice engrafted
with syngeneic BALB/c skin responded weakly to either B10.A or BALB/c
sonicates (<10 spots/million for all cytokines). Importantly, no
cytokine-producing cells were detected when responder T cells were
incubated with medium alone or with medium plus syngeneic responder
APCs (Figs. 2, A and B, and 3). Furthermore, the
T cells did not respond to sonicated donor splenocytes alone (Figs. 2C and 3), indicating 1) that the donor cells were disrupted
sufficiently to prevent any direct allorecognition, and 2) that there
were no residual responder APCs in the purified T cell population to
allow recognition of indirect pathway peptides. Moreover, direct
comparison of the enzyme-linked immunospot responses to intact donor
cells (direct pathway) or to donor sonicates plus recipient stimulators
(indirect pathway), using an H-Y-disparate donor-recipient combination
(in which the direct and indirect responses should be theoretically
equivalent), revealed that the two experimental approaches have similar
sensitivities (Fig. 4).
|
|
). Few spots were
detected in response to syngeneic BALB/c sonicates or fully allogeneic
SJL sonicates (Fig. 3), consistent with the B6 sonicate-induced
response being derived from shared minor determinants between the B10.A
and B6 strains. In summary, these results demonstrate 1) that the overwhelming majority of the allostimulator induced cytokines were produced by responder T cells, 2) that direct anti-B10.A alloreactivity dominated the alloresponse at this time point, and 3) that the assay was capable of detecting both indirect recognition and an expected cross-priming response to minor determinants.
We also determined the frequency of cytokine-producing T cells reactive
to peptide, Akß58–71 (I-Ap), a known
immunodominant determinant on the donor Ak MHC class II
molecule that is presented via the indirect pathway in the BALB/c
anti-B10.A graft combination (2, 9, 12). Assay parameters were
again optimized by testing responses to a range of peptide
concentrations, which revealed that the response reached a plateau for
all cytokines at 10 µM I-Ap (Fig. 5A). This peptide
concentration was used for all subsequent experiments. Responder T
cells produced IFN-, IL-2, and some IL-4 when incubated with
responder APCs and I-Ap (Fig. 5B). Essentially no
I-Ap-specific response was detected using T cells purified from naive
mice or purified from mice engrafted with syngeneic BALB/c or
third-party B6 skin (Fig. 5B). Furthermore, no enzyme-linked
immunospots were detected following T cell challenge with
HEL106–116, an H-2d-restricted,
irrelevant control peptide (Fig. 5B). The detected frequency
of 50 IFN- spots/million T cells reflects approximately 30% of the
indirect response and about 1% of the overall cytokine-producing
anti-B10.A T cell repertoire at this time point.
|
-producing,
allospecific T cells assayed on days 5, 8, 11, 14, and 21 postgraft
placement are shown in Fig. 6. Similar
results were noted for IL-2 and IL-4 producers, although at lower
overall frequencies than those noted for IFN- producers (not shown).
The grafts were visually normal on days 5–8, exhibited focal areas of
necrosis on days 10–11, and were fully rejected (>90% necrosis
of the graft) by day 14. The graft site was entirely healed by day 21.
|
A). Over the same time period,
however, the frequency of IFN--producing, MHC-reactive T cells
increased in the spleen (Fig. 6A), consistent with a change
in lymphocyte homing as they became activated/memory T cells.
A summary of the kinetics, frequency, and topography of
IFN--producing alloreactive T cells responding via the indirect
allorecognition pathway is shown in Fig. 6B. Similar to the
direct pathway responses, the indirect pathway alloreactivity was
initially detected at a higher frequency in the LN than in the spleen.
Interestingly, the indirect response peaked in both draining LNs and
spleen before full visual rejection of the skin grafts (day 11), and
then decreased rapidly by days 14–21. Indirect responses were markedly
less than direct responses at all time points, with a maximal
contribution of approximately 7.5% of the total alloreactive T cell
repertoire on day 11 (200 spots/million T cells for the indirect
pathway and 3000 spots/million T cells for the direct pathway). A
residual, low frequency, indirect response (20/million T cells) was
noted in the spleen at the 21 day point (<1% of the total
alloreactive T cell repertoire).
The results for T cells responding to the single indirect determinant,
I-Ap, are shown in Fig. 6C. Interestingly, I-Ap comprised
only a small proportion of the indirect response on day 11; 20/million
cells responded to I-Ap, while about 200/million cells responded to all
indirectly presented alloantigens. By day 21, however, the frequency of
IFN--producing, splenic T cells responding to I-Ap had decreased
only marginally to 15/million T cells (Fig. 6C) and
comprised the majority of the detectable indirect response at this time
(20/million T cells; Fig. 5B).
Finally, to characterize the late memory recall immune response, we
studied cytokine production by alloreactive T cells 6 wk after
rejection of B10.A skin grafts. The results summarized in Fig. 7 clearly show that even in a memory
response, direct pathway alloreactivity comprised >98% of the
specific anti-B10.A alloresponse, and that the quality of the
immune response remained unchanged with persistent production of
IFN-, IL-2, and IL-4. Consistent with the findings shown in Fig. 5, the entire indirect alloresponse seemed to be directed toward a single
immunodominant peptide, I-Ap, at this late time point.
|
|
Discussion |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
In the present study we used a highly sensitive ELISPOT technique (10)
to measure the frequency of recipient T cells responding to
alloantigens via direct and indirect allorecognition pathways following
allogeneic skin graft transplantation. We first observed that
approximately 1 of 200 recipient LN T cells produced cytokines in
response to intact donor MHC molecules at the time of rejection
(5000 spots/million T cells; Fig. 1B). This high
frequency, compared with the frequency of T cells responding to nominal
peptide Ags (<1 of 10,000) (12), reflects the polyclonality of direct
alloresponses and is consistent with previous measurements using
limiting dilution analysis techniques (13, 14, 15, 17).
Second, LN T cells reacting to donor-derived peptides presented by
recipient MHC (indirect pathway) represented a small but detectable
proportion of the overall alloresponse (1–5%; Figs. 1 and 5). This
result is similar to the frequency estimates of indirect alloreactivity
as determined by others using proliferative responses in human PBL (4).
Importantly, the vast majority of indirect pathway responses in our
study was found only after stimulation with specific allogeneic B10.A
sonicates plus recipient APCs (Fig. 3), implying that the indirect
alloresponse is focused upon donor-specific, MHC protein-derived
determinants. Low but detectable responses were also found following
incubation of recipient T cells with APCs plus MHC-disparate but minor
Ag-matched (C57BL/6) sonicates (Fig. 3), consistent with cross-priming
to minor histocompatibility or tissue-specific Ags.
In this BALB/c anti-B10.A donor/recipient combination, only
10–30% of the detectable indirect alloresponse was directed toward
the dominant determinant on the donor Ak MHC molecule,
I-Ap, at the time of visible skin graft rejection (Figs. 3, 5, and 6).
This is not surprising, in that donor and recipient differ at multiple
MHC class I and class II loci in addition to differences at minor Ag
loci. Accordingly, MHC class I- and class II-derived peptides (as well
as minor antigenic peptides) are probably presented by recipient APCs
to the alloreactive T cells. Our previous report showing that
immunologic tolerance to I-Ap alone was insufficient to prolong graft
survival (12) is consistent with the suggestion that multiple
indirectly presented determinants are relevant to B10.A skin graft
rejection in BALB/c recipients.
Our studies also revealed that T cell responses to donor MHC peptides
dropped dramatically as the rejection process resolved. It is
noteworthy that at this late stage nearly all the indirect alloresponse
appeared to be directed to a single peptide, the dominant determinant
on donor MHC class II Ak, I-Ap (Fig. 6). This may, at first
glance, be surprising given that we have previously proposed that
indirect allorecognition may be an important contributor to long term
rejection and that this phenomenon may be enhanced via broadening of
the indirect alloresponse to new T cell determinants on the donor MHC
molecule. We and others have, in fact, shown preliminary evidence for
Ag spreading during secondary indirect alloresponses (18, 19). This
epitope spreading has been noted only in situations of persistent graft
survival (i.e., renal allograft recipients on immunosuppression). In
the present study of acute rejection, the apparent discrepancy
may be due to the fact that once graft has been destroyed, no
graft-specific Ags remain available for presentation. Such
disappearance of alloantigen may prevent further development and
diversification of indirect alloimmune responses.
Our data further support the idea that in contrast to the diverse specificity of T cells responding to the direct pathway, the T cells responding to the indirect pathway seem to be focused on a few dominant determinants derived from donor MHC molecules. This suggests that peptide-based therapy could be designed to block indirect alloresponses and achieve selective immune intervention in allotransplantation. Supporting this hypothesis, induction of T cell tolerance to dominant peptides derived from donor MHC molecules has proven effective in delaying transplant rejection in rodents while preserving the integrity of the immune system (20, 21). These intriguing studies have required prior identification of the relevant immunodominant peptide determinants, a tedious and costly process that involves shotgun analysis of overlapping peptides derived from the donor MHC protein sequences (22). Our work reveals that, through the use of donor cell sonicates, we can detect indirect alloreactivity without having to identify the individual peptides involved. This finding may provide us with an ability to create a donor-specific sonicate capable of prolonging graft survival without the need to define the individual peptides. Such a tool could have important implications for prevention of graft rejection regardless of the specific MHC haplotypes of the donor or recipient.
Our data also show that alloreactivity is not a pure type 1 immune
response. Many groups have reported T cell production of IFN-
without IL-4 in response to alloantigens through the use of standard
ELISAs performed on 48-h culture supernatants. These findings led to a
consensus that both the primary and secondary alloresponses are
essentially pure type 1 in character. Through the use of a higher
resolution ELISPOT, however, we observed that for both the direct and
indirect alloresponses, IFN- producers generally outnumber IL-4
producers, but that IL-4-producing cells are a prominent component of
the response (10). We have further reconciled the differences between
our data and others by demonstrating that addition of blocking
anti-IL-4R Abs to mixed lymphocyte response cultures allows ready
detection of IL-4 in culture supernatants using standard ELISAs (10).
This implies that much of the IL-4 is bound up by receptors expressed
on cells within the culture and, thus, is not detected in the
supernatants. Furthermore, limiting dilution analyses performed by
other laboratories have found similar frequencies of IL-4-producing
alloreactive T cells, and many investigators have noted that IL-4
message can be found within organs undergoing rejection. We conclude
that the alloresponse develops along both type 1 and type 2 pathways,
with only relative dominance of type 1 cytokines.
The kinetic analysis of direct and indirect alloresponses during skin graft rejection revealed that while the initial T cell response was prominent in draining LNs, it diminished relatively quickly as the rejection progressed. At the same time, however, both direct and indirect responses increased in the periphery as detected by splenic recall responses. This topographic change in the response is consistent with previous studies showing that once activated, draining LN T cells down-regulate expression of the LN-homing receptor CD62L (L-selectin), migrate to the periphery, and remain as long term memory T cells in the spleen (23, 24). Additional studies by our group have confirmed that CD62L expression is down-regulated in this peripheral memory recall alloresponse (10).
The cytokine ELISPOT is presently the most comprehensive approach to
measuring alloreactivity in response to a given set of Ags. However,
cytokine enzyme-linked immunospot frequencies detected after
stimulation with intact allogeneic cells, sonicated cell preparations,
and synthetic peptides may not be directly comparable, as the various
alloantigen preparations and their abilities to interact with APCs may
differ. Nonetheless, our data suggest that the sensitivities of
detecting direct and indirect responses using these two techniques are
similar (Fig. 4), thus allowing us to make reasonable conclusions
regarding the relative contributions of direct and indirect recognition
to the alloimmune repertoire. Furthermore, the alloimmune responses
detected by these techniques behaved as one might have predicted based
on previously published work using less sensitive assays. The indirect
response represented only a small proportion of the overall
alloresponse, cross-priming to minor determinants was detectable and
was noted at a lower frequency than priming to MHC-derived
determinants, the response to a single indirectly presented peptide
(I-Ap) was less frequent than the response to all indirectly presented
allo-determinants, and the cytokines produced by direct and indirect
alloreactive T cells were dominated by type 1 cytokines. Thus, the
results of the assay seem to reflect what is presently understood
regarding the in vivo alloresponse in many respects.
In conclusion, our study provides a comprehensive analysis of in vivo T cell responses to donor Ags during allotransplant rejection. We established the frequency and phenotype of alloreactive T cells that responded to allogeneic MHC Ags via direct and indirect allorecognition pathways. T cells recognizing processed donor MHC peptides appeared to represent a sizable proportion of the overall alloresponse, a finding that further supports their important role in the rejection process. In contrast to previous reports, we found that the alloresponse was mediated by T cells that displayed a mixed type 1/type 2 phenotype. Whether alloreactive type 2 cytokine-secreting T cells contribute to the rejection process remains open to question. We observed that the T cell response to a single dominant donor MHC peptide represented 10–30% of the initial indirect anti-B10.A alloresponse and accounted for most of the memory T cell response after BALB/c rejection of B10.A skin. This finding indicates that immunodominance is an essential feature of indirect alloresponse. It also shows that under certain circumstances T cell responses can either diversify to newly presented determinants (Ag spreading) or focus on a single dominant peptide (Ag focusing). To design new strategies to achieve transplantation tolerance using peptides, it is now essential to further explore the mechanisms underlying immunodominance in T cell response to donor MHC. Finally, our study provides a new approach to analyze and understand the physiology of allograft rejection in animal models. Such an approach may also be useful for the monitoring of immune responses to graft Ags and for predicting rejection in transplanted patients.
|
Footnotes |
|---|
2 Address correspondence and reprint requests to Dr. Peter S. Heeger, Nephrology Division, Department of Medicine, Cleveland Veterans Affairs Medical Center, 111K(W), 10701 East Boulevard, Cleveland, OH 44106. E-mail address:
3 Abbreviations used in this paper: ELISPOT, enzyme-linked immunospot assay; LN, lymph node; MMC, mitomycin C; I-Ap, peptide I-Akß58–71.
Received for publication January 7, 1998. Accepted for publication September 4, 1998.
|
References |
|---|
|
TopAbstractIntroductionMaterials and MethodsResultsDiscussionReferences |
|---|
This article has been cited by other articles:
|
|
 |
|
  J. El Annan, S. K. Chauhan, T. Ecoiffier, Q. Zhang, D. R. Saban, and R. Dana Characterization of Effector T Cells in Dry Eye Disease Invest. Ophthalmol. Vis. Sci., August 1, 2009; 50(8): 3802 - 3807. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. Nozaki, J. M. Rosenblum, D. Ishii, K. Tanabe, and R. L. Fairchild CD4 T Cell-Mediated Rejection of Cardiac Allografts in B Cell-Deficient Mice J. Immunol., October 15, 2008; 181(8): 5257 - 5263. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
V. Pavlov, H. Raedler, S. Yuan, S. Leisman, W.-h. Kwan, P. N. Lalli, M. E. Medof, and P. S. Heeger Donor Deficiency of Decay-Accelerating Factor Accelerates Murine T Cell-Mediated Cardiac Allograft Rejection J. Immunol., October 1, 2008; 181(7): 4580 - 4589. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
W. F. N. Chan, H. Razavy, and C. C. Anderson Differential Susceptibility of Allogeneic Targets to Indirect CD4 Immunity Generates Split Tolerance J. Immunol., October 1, 2008; 181(7): 4603 - 4612. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. Bharat, E. Kuo, N. Steward, A. Aloush, R. Hachem, E. P. Trulock, G. A. Patterson, B. F. Meyers, and T. Mohanakumar Immunological Link Between Primary Graft Dysfunction and Chronic Lung Allograft Rejection Ann. Thorac. Surg., July 1, 2008; 86(1): 189 - 197. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. N. Morrell, K. Murata, A. M. Swaim, E. Mason, T. V. Martin, L. E. Thompson, M. Ballard, K. Fox-Talbot, B. Wasowska, and W. M. Baldwin III In Vivo Platelet-Endothelial Cell Interactions in Response to Major Histocompatibility Complex Alloantibody Circ. Res., April 11, 2008; 102(7): 777 - 785. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
L. Shen, Y. Jin, G. J. Freeman, A. H. Sharpe, and M. R. Dana The Function of Donor versus Recipient Programmed Death-Ligand 1 in Corneal Allograft Survival J. Immunol., September 15, 2007; 179(6): 3672 - 3679. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Golshayan, S. Jiang, J. Tsang, M. I. Garin, C. Mottet, and R. I. Lechler In vitro-expanded donor alloantigen-specific CD4+CD25+ regulatory T cells promote experimental transplantation tolerance Blood, January 15, 2007; 109(2): 827 - 835. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Noorchashm, A. J. Reed, S. Y. Rostami, R. Mozaffari, G. Zekavat, B. Koeberlein, A. J. Caton, and A. Naji B Cell-Mediated Antigen Presentation Is Required for the Pathogenesis of Acute Cardiac Allograft Rejection J. Immunol., December 1, 2006; 177(11): 7715 - 7722. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Q. Peng, K. Li, H. Patel, S. H. Sacks, and W. Zhou Dendritic Cell Synthesis of C3 Is Required for Full T Cell Activation and Development of a Th1 Phenotype J. Immunol., March 15, 2006; 176(6): 3330 - 3341. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 J. S. Neto, A. Nakao, H. Toyokawa, M. A. Nalesnik, A. J. Romanosky, K. Kimizuka, T. Kaizu, N. Hashimoto, O. Azhipa, D. B. Stolz, et al. Low-dose carbon monoxide inhalation prevents development of chronic allograft nephropathy Am J Physiol Renal Physiol, February 1, 2006; 290(2): F324 - F334. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
H. Amano, A. Bickerstaff, C. G. Orosz, A. C. Novick, H. Toma, and R. L. Fairchild Absence of Recipient CCR5 Promotes Early and Increased Allospecific Antibody Responses to Cardiac Allografts J. Immunol., May 15, 2005; 174(10): 6499 - 6508. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Schenk, D. D. Kish, C. He, T. El-Sawy, E. Chiffoleau, C. Chen, Z. Wu, S. Sandner, A. V. Gorbachev, K. Fukamachi, et al. Alloreactive T Cell Responses and Acute Rejection of Single Class II MHC-Disparate Heart Allografts Are under Strict Regulation by CD4+CD25+ T Cells J. Immunol., March 15, 2005; 174(6): 3741 - 3748. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Watson, G. Y. Zhang, M. Sartor, and S. I. Alexander "Pruning" of Alloreactive CD4+ T Cells Using 5- (and 6-)Carboxyfluorescein Diacetate Succinimidyl Ester Prolongs Skin Allograft Survival J. Immunol., December 1, 2004; 173(11): 6574 - 6582. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Huq, Y. Liu, G. Benichou, and M. R. Dana Relevance of the Direct Pathway of Sensitization in Corneal Transplantation Is Dictated by the Graft Bed Microenvironment J. Immunol., October 1, 2004; 173(7): 4464 - 4469. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 T. L. Sumpter and D. S. Wilkes Role of autoimmunity in organ allograft rejection: a focus on immunity to type V collagen in the pathogenesis of lung transplant rejection Am J Physiol Lung Cell Mol Physiol, June 1, 2004; 286(6): L1129 - L1139. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Z. Wang, A. Castellaneta, A. De Creus, W. J. Shufesky, A. E. Morelli, and A. W. Thomson Heart, but Not Skin, Allografts from Donors Lacking Flt3 Ligand Exhibit Markedly Prolonged Survival Time J. Immunol., May 15, 2004; 172(10): 5924 - 5930. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Chen, P. S. Heeger, and A. Valujskikh In Vivo Helper Functions of Alloreactive Memory CD4+ T Cells Remain Intact Despite Donor-Specific Transfusion and Anti-CD40 Ligand Therapy J. Immunol., May 1, 2004; 172(9): 5456 - 5466. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 Y. Chen, Y. Demir, A. Valujskikh, and P. S. Heeger Antigen Location Contributes to the Pathological Features of a Transplanted Heart Graft Am. J. Pathol., April 1, 2004; 164(4): 1407 - 1415. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. Gasser, A. M. Waaga-Gasser, J. E. Kist-van Holthe, X. Yuan, S. M. Lenhard, K. A. Abdallah, and A. Chandraker Chronic Rejection: Insights from a Novel Immunosuppressive-Free Model of Kidney Transplantation J. Am. Soc. Nephrol., March 1, 2004; 15(3): 687 - 694. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y.-M. Kim, M. Y. Mapara, J. D. Down, K. W. Johnson, F. Boisgerault, Y. Akiyama, G. Benichou, M. Pelot, G. Zhao, and M. Sykes Graft-versus-host-reactive donor CD4 cells can induce T cell-mediated rejection of the donor marrow in mixed allogeneic chimeras prepared with nonmyeloablative conditioning Blood, January 15, 2004; 103(2): 732 - 739. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. He, S. Schenk, Q. Zhang, A. Valujskikh, J. Bayer, R. L. Fairchild, and P. S. Heeger Effects of T Cell Frequency and Graft Size on Transplant Outcome in Mice J. Immunol., January 1, 2004; 172(1): 240 - 247. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. J. Reed, H. Noorchashm, S. Y. Rostami, Y. Zarrabi, A. R. Perate, A. N. Jeganathan, A. J. Caton, and A. Naji Alloreactive CD4 T Cell Activation In Vivo: An Autonomous Function of the Indirect Pathway of Alloantigen Presentation J. Immunol., December 15, 2003; 171(12): 6502 - 6509. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Chen, Y. Demir, A. Valujskikh, and P. S. Heeger The Male Minor Transplantation Antigen Preferentially Activates Recipient CD4+ T Cells through the Indirect Presentation Pathway In Vivo J. Immunol., December 15, 2003; 171(12): 6510 - 6518. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Andrassy, S. Kusaka, E. Jankowska-Gan, J. R. Torrealba, L. D. Haynes, B. R. Marthaler, R. C. Tam, B. M.-W. Illigens, N. Anosova, G. Benichou, et al. Tolerance to Noninherited Maternal MHC Antigens in Mice J. Immunol., November 15, 2003; 171(10): 5554 - 5561. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
G. Andersson, B. M. W. Illigens, K. W. Johnson, D. Calderhead, C. LeGuern, G. Benichou, M. E. White-Scharf, and J. D. Down Nonmyeloablative conditioning is sufficient to allow engraftment of EGFP-expressing bone marrow and subsequent acceptance of EGFP-transgenic skin grafts in mice Blood, June 1, 2003; 101(11): 4305 - 4312. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 W. Chalermskulrat, I. P. Neuringer, W. J. Brickey, N. J. Felix, S. H. Randell, J. P. Ting, and R. M. Aris Hierarchical Contributions of Allorecognition Pathways in Chronic Lung Rejection Am. J. Respir. Crit. Care Med., April 1, 2003; 167(7): 999 - 1007. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
B. Pantenburg, F. Heinzel, L. Das, P. S. Heeger, and A. Valujskikh T Cells Primed by Leishmania major Infection Cross-React with Alloantigens and Alter the Course of Allograft Rejection J. Immunol., October 1, 2002; 169(7): 3686 - 3693. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. V. Fedoseyeva, K. Kishimoto, H. K. Rolls, B. M.-W. Illigens, V. M. Dong, A. Valujskikh, P. S. Heeger, M. H. Sayegh, and G. Benichou Modulation of Tissue-Specific Immune Response to Cardiac Myosin Can Prolong Survival of Allogeneic Heart Transplants J. Immunol., August 1, 2002; 169(3): 1168 - 1174. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
E. Chiffoleau, G. Beriou, P. Dutartre, C. Usal, J.-P. Soulillou, and M. C. Cuturi Role for Thymic and Splenic Regulatory CD4+ T Cells Induced by Donor Dendritic Cells in Allograft Tolerance by LF15-0195 Treatment J. Immunol., May 15, 2002; 168(10): 5058 - 5069. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Guillet, S. Brouard, K. Gagne, F. Sebille, M.-C. Cuturi, M.-A. Delsuc, and J.-P. Soulillou Different Qualitative and Quantitative Regulation of V{beta} TCR Transcripts During Early Acute Allograft Rejection and Tolerance Induction J. Immunol., May 15, 2002; 168(10): 5088 - 5095. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 D. Wang, X. Gong, P. S. Heeger, F. Rininsland, G. C. Bazan, and A. J. Heeger Biosensors from conjugated polyelectrolyte complexes PNAS, December 21, 2001; (2001) 12581399. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
R. J. Baker, M. P. Hernandez-Fuentes, P. A. Brookes, A. N. Chaudhry, H. T. Cook, and R. I. Lechler Loss of Direct and Maintenance of Indirect Alloresponses in Renal Allograft Recipients: Implications for the Pathogenesis of Chronic Allograft Nephropathy J. Immunol., December 15, 2001; 167(12): 7199 - 7206. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
F. Boisgerault, Y. Liu, N. Anosova, E. Ehrlich, M. R. Dana, and G. Benichou Role of CD4+ and CD8+ T Cells in Allorecognition: Lessons from Corneal Transplantation J. Immunol., August 15, 2001; 167(4): 1891 - 1899. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
M. Y. Braun, I. Grandjean, P. Feunou, L. Duban, R. Kiss, M. Goldman, and O. Lantz Acute Rejection in the Absence of Cognate Recognition of Allograft by T Cells J. Immunol., April 15, 2001; 166(8): 4879 - 4883. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. C. Anderson, J. M. Carroll, S. Gallucci, J. P. Ridge, A. W. Cheever, and P. Matzinger Testing Time-, Ignorance-, and Danger-Based Models of Tolerance J. Immunol., March 15, 2001; 166(6): 3663 - 3671. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
C. V. Hartig, G. W. Haller, D. H. Sachs, S. Kuhlenschmidt, and P. S. Heeger Naturally Developing Memory T Cell Xenoreactivity to Swine Antigens in Human Peripheral Blood Lymphocytes J. Immunol., March 1, 2000; 164(5): 2790 - 2796. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
D. Wang, X. Gong, P. S. Heeger, F. Rininsland, G. C. Bazan, and A. J. Heeger Biosensors from conjugated polyelectrolyte complexes PNAS, January 8, 2002; 99(1): 49 - 53. [Abstract] [Full Text] [PDF]
|
|
| |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
