The role of CTLA-4 in tolerance induction and Ttigen administration cell differentiation in experimental autoimmune encephalomyelitis: i.v. antigen administration
Robert B. Ratts,
Lachelle R. Arredondo,
Patrice Bittner,
Peter J. Perrin1,
Amy E. Lovett-Racke and
Michael K. Racke
Department of Neurology, Washington University School of Medicine, St Louis, MO 63110, USA
1 Department of Medicine, University of Pennsylvania School of Medicine, Philadelphia, PA 19104, USA
Correspondence to:
M. K. Racke, Department of Neurology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75235-9036, USA
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Abstract
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Interactions between B7 molecules on antigen-presenting cells and CTLA-4 on T cells have been shown to be important in establishing tolerance. In the present study, we examined the kinetics of tolerance induction following i.v. administration of myelin basic protein (MBP) Ac111 in mice transgenic for a TCR Vß8.2 gene derived from an encephalitogenic T cell clone specific for MBP Ac111. Examination of the lymph node cell (LNC) response 10 days after antigen administration demonstrated an accentuation of i.v. tolerance induction with anti-CTLA-4 blockade. Anergy was induced in splenocytes by i.v. antigen administration as shown by a decrease in MBP-specific proliferation and IL-2 production, and anti-CTLA-4 potentiated this effect. In addition, i.v. antigen plus anti-CTLA-4 and complete Freund's adjuvant was not encephalitogenic. Interestingly, i.v. tolerance (a single injection) did not inhibit experimental autoimmune encephalomyelitis (EAE) and anti-CTLA-4 administration did not alter this phenotype. These results suggest that while the majority of MBP-specific T cells are tolerized by i.v. antigen and that this process is potentiated by anti-CTLA-4 administration, a population of T cells remains that is quite efficient in mediating EAE.
Keywords: experimental autoimmune encephalomyelitis, co-stimulatory molecules, neuroimmunology, tolerance
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Introduction
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T cells require two signals to become activated and differentiate. Signal one occurs when the TCR complex recognizes antigen bound to MHC molecules on the surface of antigen-presenting cells (APC). This interaction determines the antigen specificity of the immune response. Signal two, termed co-stimulation, is provided by accessory molecules on the APC and T cell, and appears to be necessary for functional T cell activation. While there are several TCRligand pairs which can provide co-stimulation, the signal provided by the B7 family of surface molecules with its receptors on T cells, CD28 and CTLA-4, appear to predominate in T cell activation (13). At least two members of the B7 family have been defined B7-1 (CD80) and B7-2 (CD86) (48). These molecules, although having modest homology, are each capable of providing co-stimulation to T cells for proliferation and IL-2 production. It is probably for this reason that a mouse genetically deficient in B7-1 was essentially immuno-competent (4). On the other hand, T cells from a mouse deficient for CD28 could not produce IL-2 after stimulation with the mitogenic lectin concanavalin A, suggesting that co-stimulation through this molecule is critical for IL-2 production (9). Recent evidence suggests that co-stimulation provided by B7 molecules through CTLA-4 is also important in several different methods used to establish peripheral tolerance in vivo (1013). Thus, by engaging either CD28 or CTLA-4, B7 molecules themselves are able to either enhance or inhibit immune responses.
During recent years the understanding of immunological mechanisms involved in autoimmune demyelination has been greatly advanced by the study of experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis. EAE can be induced either by immunization of susceptible animals with components of myelin or by the adoptive transfer of CD4+ T cells specific for myelin antigens (14,15). These encephalitogenic T cells produce lymphotoxin and IFN-
, but little IL-4 (14,15). B7 co-stimulation can contribute to IFN-
secretion by Th1 clones (16). Much has been learned about the role of co-stimulation in EAE using a soluble fusion protein, CTLA-4Ig, which can prevent the interaction between B7 and CD28 or CTLA-4 (17). Our laboratory has examined the role of B7:CD28/CTLA-4 interaction in the induction of EAE (18,19). In the adoptive transfer model of EAE, CTLA-4Ig was able to inhibit the proliferation and IL-2 production of MBP-specific lymph node cells (LNC) during activation in vitro, resulting in reduced clinical disease upon subsequent transfer. Thus, B7-mediated co-stimulation was found to be an important factor in determining encephalitogenicity.
Studies by our laboratory have demonstrated that high-dose i.v. antigen therapy results in the elimination of MBP-specific, autoreactive T cells (20,21). These studies demonstrated that multiple injections of antigen were much more effective in eliminating MBP-specific T cells and having a therapeutic benefit than a single injection. However, the co-stimulation requirements for i.v. tolerance in the EAE model remain ill defined. In addition, examination of co-stimulation requirements in antigen-specific tolerance have largely been confined to lymph node responses and ignored antigen-specific responses in the spleen.
We have previously used T cells from MBP-specific TCR transgenic mice to follow the fate of encephalitogenic T cells in vivo following i.v. tolerance (20,22). In this study, we used the Vß8.2 TCR transgenic mice to examine the role of CTLA-4 in establishing tolerance following i.v. administration of antigen (23,24). In addition, we have used the EAE model as a means of determining the functional significance of CTLA-4 blockade during i.v. antigen administration in the autoimmune disorder, EAE.
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Methods
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Mice
Transgenic mice bearing the rearranged Vß8.2 gene specific for MBP Ac111 on the B10.PL background were provided by Dr Joan Goverman (University of Washington, Seattle, WA) (2224). These mice were bred and maintained in our animal colony at Washington University School of Medicine in compliance with the Animal Studies Committee. All mice were 68 weeks of age when experiments were initiated.
Reagents
Whole MBP was prepared from guinea pig spinal cords as previously described and purity assessed by SDSPAGE (25). MBP peptide Ac111 was synthesized by the Protein Chemistry Laboratory at Washington University School of Medicine with purity assessed by mass spectrometry. Hamster anti-mouse CTLA-4 mAb UC10-4F10 was provided by Dr Jeff Bluestone (University of Chicago, Chicago, IL) (26). Hamster IgG was purchased from Jackson ImmunoResearch (West Grove, PA).
Antigenic challenges
At day 0, mice were immunized s.c. with MBP Ac111 (30 µg) in incomplete Freund's adjuvant (IFA; Difco, Detroit, MI) in the primed group. Mice in the i.v. tolerized group received MBP Ac111 (200 µg) in PBS (0.2 ml).
In vivo antibody treatments
Anti-CTLA-4 mAb (200 µg) or control hamster IgG (200 µg) were given on days 1, 0 and +1 relative to i.v. antigen administration.
Lymphocyte proliferation
Proliferative responses by LNC and splenocytes were measured 3 and 10 days after antigenic challenge. Results shown are representative of two to three experiments. Cells (2x105/well) were incubated with MBP or media alone as indicated. Cultures were maintained in 96-well, flat-bottom microtiter plates for 96 h at 37°C in humidified 5% CO2 air. The wells were pulsed with 0.5 µCi/well of [3H]methyl-thymidine for the final 16 h of culture. Cells were harvested on glass fibers and incorporated [3H]methyl-thymidine was measured with a Betaplate counter (Wallac, Gaithersburg, MD). Results were determined as means from quadruplicate cultures and are shown on log scale with SEM.
Measurement of cytokine production
An IL-2-dependent cell line, CTLL.EV (27), was generously provided by Dr Jonathan Katz (Washington University School of Medicine, St Louis, MO). Aliquots of 20 µl of supernatants from experimental cell cultures were assayed in quadruplicate. Results were compared with proliferation of the cell line to known amounts of IL-2 (R & D System, Minneapolis, MN) as standards. IFN-
and IL-4 ELISA (R & D Systems) were performed in duplicate according to the manufacturer's instructions. Cytokine results are representative of three to six experiments.
Induction of EAE
Ten days after receiving i.v. antigen and i.p. antibody, mice were immunized with MBP Ac111/complete Freund's adjuvant (CFA) (200 µg) s.c. over the flanks. Mice were examined daily for signs of disease and graded on the following scale: 0, no abnormality; 1, a limp tail; 2, moderate hind limb weakness; 3, severe hind limb weakness; 4, complete hind limb paralysis; 5, quadriplegia or premoribund state (1921,28).
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Results
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Vß8.2 TCR transgenic mice have increased frequency of MBP-specific T cells
To determine if naive B10.PL mice transgenic for the Vß8.2 TCR derived from an encephalitogenic T cell clone have a higher frequency of MBP-specific T cells than wild-type B10.PL mice, a proliferation assay was performed. LNC and splenocytes from Vß8.2 TCR transgenic mice demonstrated a robust proliferative response to MBP compared to cells from wild-type mice (29). Limiting dilution analysis estimated the frequency of MBP-specific cells to be ~1/163,000 (data not shown), which is significantly higher than the frequency in naive, wild-type B10.PL mice (<1/830,000 ) (data not shown). Due to the high frequency of naive MBP-specific T cells in these mice, they provided an informative system for studying tolerance induction in the EAE model and were used for all subsequent experiments.
Tolerance induction after i.v. administration of antigen
Previously anti-CTLA-4 has been reported to block tolerance induction by i.v. administration of antigen (OVA peptide 323339) (30). To determine if i.v. tolerance induction to a self-antigen was dependent on CTLA-4 engagement, we compared the proliferative responses of LNC from naive mice, mice primed with MBP Ac111 s.c., mice receiving i.v. MBP Ac111 and mice receiving i.v. MBP Ac111 with anti-CTLA-4. When B10.PL Vß8.2 TCR transgenic were mice primed with 30 µg MBP Ac111/IFA s.c., their LNC at day 3 and 10 demonstrated an enhanced proliferative response compared to naive LNC (Figs 1 and 2
) To determine the kinetics of i.v. tolerance induction, proliferative responses were examined at 3 and 10 days post antigen administration. Three days following administration of i.v. MBP Ac111, a decreased proliferative response was observed in LNC, which was partly reversed by anti-CTLA-4 administration (Fig. 1
), similar to prior observations (10). Surprisingly, at day 10 following i.v. administration of antigen, anti-CTLA-4 accentuated inhibition of MBP-specific proliferation by LNC (Fig. 2
), while a single injection of MBP i.v. did not demonstrate a tolerogenic response at 10 days as determined by MBP-specific proliferation. In the spleen 3 days following i.v. administration of antigen, a mild decrease in antigen-specific proliferation was observed and anti-CTLA-4 had no noticeable effect (Fig. 3A
). MBP-specific IL-2 and IFN-
production were reduced by splenocytes 3 days after i.v. MBP Ac111, and anti-CTLA-4 further reduced IL-2 and IFN-
production (Fig. 3B and C
). IL-4 production was not significantly affected by the different protocols (Fig. 3D
). At 10 days following i.v. antigen administration, a decrease in MBP-specific splenocyte proliferation was observed and anti-CTLA-4 again resulted in further inhibition of proliferation (Fig. 4A
). Cytokine (IL-2, IL-4 and IFN-
) production at 10 days following i.v. antigen administration was all reduced compared to naive splenocytes (Fig. 4B and D
). Antigen administered i.v. did not appear to induce Th2 differentiation of antigen-specific T cells in the spleen, but rather anergy, which was demonstrated by decreased proliferation, IL-2 and IFN-
production.

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Fig. 1. MBP-specific LNC proliferation 3 days after i.v. antigen administration in vivo. LNC were removed from B10.PL Vß8.2 TCR transgenic mice 3 days after the mice were unmanipulated (closed squares), tolerized with 200 µg MBP Ac111 i.v. and hamster IgG (open circles) or tolerized with 200 µg MBP Ac111 i.v. and anti-CTLA-4 antibody (4F10) (open squares). The resulting LNC were cultured with whole MBP as described in Methods. Proliferation was measured by 3H-labeled thymidine incorporation assay as described in Methods. SEM are shown from quadruplicate cultures.
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Fig. 2. Anti-CTLA-4 does not block i.v. tolerance in lymph nodes 10 days following tolerogen. Two days prior to administration of 200 µg MBP Ac111 i.v. anti-CTLA-4 (open squares) or control antibody (open circles) were injected into B10.PL Vß8.2 TCR transgenic mice. As a further control mice some mice were unmanipulated (closed squares). LNC were harvested 10 days after antigen treatment. The resulting LNC were cultured with whole MBP as described in Methods. Proliferation was measured by 3H-labeled thymidine incorpora- tion assay as described in Methods. SEM are shown from quadruplicate cultures.
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Fig. 3. MBP-specific splenocyte responses 3 days after i.v. antigenic challenge in vivo. Spleens were removed from B10.PL Vß8.2 TCR transgenic mice 3 days after the mice were unmanipulated (closed squares), primed with 30 µg MBP Ac111/IFA s.c. (closed circles), tolerized with 200 µg MBP Ac111 i.v. and hamster IgG (open circles) or tolerized with 200 µg MBP Ac111 i.v. and anti-CTLA-4 antibody (4F10) (open squares). The resulting splenocytes were cultured with whole MBP as described in Methods. Supernatants were taken at 24, 48 and 72 h, and frozen at 20°C. IL-2 concentrations were determined by CTLL-2 assay. IL-4 and IFN- production was determined by ELISA. Proliferation was measured by 3H-labeled thymidine incorporation assay as described in Methods. SEM are shown from quadruplicate cultures (A and B) and 1 SD is shown from duplicate wells (C and D).
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Fig. 4. MBP-specific splenocyte responses 10 days after i.v. antigen challenge in vivo. Spleens were removed from B10.PL Vß8.2 TCR transgenic mice 10 days after the mice were unmanipulated (closed squares), primed with 30 µg MBP Ac111/IFA s.c. (closed circles) tolerized with 200 µg MBP Ac111 i.v. and hamster IgG (open circles) or tolerized with 200 µg MBP Ac111 i.v. and anti-CTLA-4 antibody (4F10) (open squares). The resulting splenocytes were cultured with whole MBP as described in Methods. Supernatants were taken at 24, 48 and 72 h, and frozen at 20°C. IL-2 concentrations were determined by CTLL-2 assay. IL-4 and IFN- production was determined by ELISA. SEM are shown from quadruplicate cultures (A and B) and 1 SD is shown from duplicate wells (C and D).
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Local inflammation prevents induction of T cell anergy in vivo, but does not result in encephalitogenic response
Because a prior study had shown that local inflammation with i.v. antigen and anti-CTLA-4 resulted in an immunogenic response (30), we wished to ask whether it would result in an encephalitogenic response. Vß8.2 TCR transgenic mice were challenged with CFA, i.v. antigen and anti-CTLA-4 (200 µg i.p.), and examined for signs of EAE. None of the mice receiving this protocol developed signs of EAE (Table 1
). Examination of the proliferative response to MBP from draining LNC showed that the dramatic reduction in proliferative response observed 10 days after challenge with i.v. antigen and anti-CTLA-4 was abrogated in an inflammatory environment (Fig. 5
).

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Fig. 5. An inflammatory environment alters LNC proliferative response following i.v. antigen administration. Vß8.2 TCR transgenic mice received CFA s.c. and an injection of 200 µg of either anti-CTLA-4 (A) or control IgG (B) 24 h before receiving an injection of MBP Ac111 (400 µg i.v. in a single dose) or saline. Similar groups of mice received anti-CTLA-4 (C) or control IgG (D) and either MBP Ac111 or saline without CFA. Ten days later, LNC from Vß8.2 TCR transgenic mice were removed and stimulated in vitro with MBP in a standard 4 day proliferation assay. SEM are shown from quadruplicate cultures.
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The effects of anti-CTLA-4 administration on tolerance induction and susceptibility to EAE
Because 100% of immunized B10.PL Vß8.2 TCR transgenic mice develop EAE when challenged s.c. with MBP Ac111/CFA (Table 1
), we decided to examine the effects of i.v. antigen administration on EAE susceptibility. Mice were tolerized with i.v. administration of MBP Ac111 as before and reimmunized 10 days later with 200 µg MBP Ac111/CFA s.c. Mice were then observed for clinical signs of EAE. These mice developed severe EAE, irrespective of anti-CTLA-4 administration (Table 1
). This is consistent with our prior observations that a single injection of i.v. MBP was unable to inhibit EAE (20,21). Thus, i.v. tolerance (at least a single injection) appears to be ineffective in inhibiting EAE, with anti-CTLA-4 administration having little effect on disease outcome, despite having a profound effect in reducing MBP-specific splenocyte proliferation, IL-2 and IFN-
production.
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Discussion
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In the present study, we examined the effect of i.v. antigen administration on the effect of cytokine production, lymphocyte proliferation and ability to induce the organ-specific autoimmune disorder, EAE. In particular, we also addressed the role of CTLA-4 in these processes. Immune responses induced by a protein antigen can be suppressed when that same antigen is administered i.v. to adult animals. This form of tolerance, sometimes referred to as `high antigen dose suppression' or `high zone tolerance', involves extrathymic mechanisms (31).
Consistent with our prior observations, a single injection of i.v. antigen was unable to block the induction of EAE (Table 1
). However, based on the readouts of proliferation and cytokine production, it appeared that a significant proportion of antigen-specific T cells had been anergized or deleted. This is consistent with recent observations that clonal anergy can contribute to tolerance by limiting the size of the antigen-specific responder population, but it may not disrupt its effector function (32). Another possibility is that i.v. antigen administration may activate a small preprimed population of T cells, which are then capable of causing EAE when challenged with MBP Ac111/CFA. Thus, despite dramatically affecting the MBP-specific proliferative response and IL-2 production in response to antigen, i.v. tolerance was unable to have an inhibitory effect on the induction of EAE, at least when given as a single injection of antigen.
A recent study has examined the role of IL-12 and B7-mediated co-stimulation in T cell anergy in vivo (30). These authors demonstrated that high doses of antigen in the absence of adjuvant could be immunogenic in the presence of IL-12 and anti-CTLA-4. Furthermore, they demonstrated that IL-12 was crucial for Th1 differentiation, while anti-CTLA-4 was important in establishing a proliferative response.
Our observation that anti-CTLA-4 seems to dramatically enhance tolerance in splenocytes when administered with i.v. antigen after 10 days is intriguing. It has been shown that when anti-CTLA-4 is administered with antigen, in vivo clonal expansion is greatly enhanced (30). It is likely that following i.v. administration of MBP in the Vß8.2 TCR transgenic mouse, that a similar expansion would take place. These T cells may be very susceptible to antigen-induced cell death upon subsequent stimulation in vitro, producing the types of observations shown in Figs 14


. On the other hand, it may be that the expansion noted after 3 days cannot be sustained in the absence of adjuvant, resulting in our observations noted 10 days after antigen challenge. However, as noted above, some MBP-specific T cells may have differentiated into Th1 effector cells following i.v. antigen administration and these cells could then participate in the encephalitogenic response (Table 1
). MBP-specific T cells which had been activated may have trafficked out of the peripheral lymph nodes, which are normally the site for recruitment of L-selectin+ naive T cells. Prior studies have also demonstrated that i.v. antigen can be immunogenic when administered with anti-CTLA-4 in an inflammatory environment elicited by CFA (30). Our studies would suggest that while this may also be the case in our system, i.v. antigen with CFA and anti-CTLA-4 does not result in an encephalitogenic response (Table 1
). It will be interesting to determine whether the combination of i.v. antigen, anti-CTLA-4 and CFA affects the ability of encephalitogenic T cells to home to the CNS.
Overall, our findings suggest that the route of antigen administration is very important in determining the phenotype of the responding T cells and the contribution that CTLA-4 may play in that differentiation. Recent work by our group has shown that i.p. antigen administration results in a Th2 response by splenic T cells, which is potentiated by anti-CTLA-4 administration (29). In addition, these studies on i.v. tolerance point out that in vitro assays on antigen-specific cell populations may not necessarily reflect what will happen with regard to an encephalitogenic response. Our studies demonstrate that while there may be functional impairment of certain populations of antigen-specific T cells following exposure to antigen in vivo, that this impairment may not necessarily mean that effector responses such as those required for development of EAE are impaired.
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Acknowledgments
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This research was supported by grants from the National Multiple Sclerosis Society (M. K. R. and P. J. P.) and NIH (R29-AI-43296 to P. J. P. and RO1-NS-37513 to M. K. R.). M. K. R. is a Harry Weaver Neuroscience Scholar of the National Multiple Sclerosis Society, and the Young Investigator in Multiple Sclerosis of the American Academy of Neurology Education and Research Foundation.
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Abbreviations
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APC antigen-presenting cell |
CFA complete Freund's adjuvant |
EAE experimental autoimmune encephalomyelitis |
IFA incomplete Freund's adjuvant |
LNC lymph node cells |
MS multiple sclerosis |
MBP myelin basic protein |
OVA ovalbumin |
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Notes
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Transmitting editor: L. Steinman
Received 3 June 1999,
accepted 12 August 1999.
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References
|
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-
June, C. H., Bluestone, J. A., Nadler L. M. and Thompson, C. B. 1994. The B7 and CD28 receptor families. Immunol. Today 15:321.[ISI][Medline]
-
Jenkins, M. K. and Johnson, J. G. 1993. Molecules involved in T-cell co-stimulation. Curr. Opin. Immunol. 5:351.
-
Bretscher, P. 1992. The two-signal model of lymphocyte activation twenty-one years later. Immunol. Today 13:74.[ISI][Medline]
-
Freeman, G. J., Borriello, F., Hodes, R. J., Reiser, H., Hathcock, K. S., Laszlo, G., McKnight, A. J., Kim, J., Du, L., Lombard, D. B., Gray, G. S., Nadler, L. M. and Sharp, A. H. 1993. Uncovering of functional alternative CTLA-4 counter-receptor in B7-deficient mice. Science 262:907.[ISI][Medline]
-
Freeman, G. J., Gribben, J. G., Boussiotis, V. A., Ng, J., Restivo, V. A., Lombard, L. A., Gray, G. S. and Nadler, L. M. 1993. Cloning of B7-2: a CTLA-4 counter-receptor that co-stimulates human T cell proliferation. Science 262:909.[ISI][Medline]
-
Hathcock, K. S., Laszlo, G., Pucillo, C., Linsley, P. and Hodes, R. J. 1994. Comparative analysis of B7-1 and B7-2 co-stimulatory ligands: expression and function. J. Exp. Med. 180:631.[Abstract]
-
Freeman, G. J., Freedman, A. S., Segil, J. M., Lee, G., Whitman, J. F. and Nadler, L. M. 1989. B7, a new member of the Ig superfamily with unique expression on activated and neoplastic B cells. J. Immunol. 143:2714.[Abstract/Free Full Text]
-
Freeman, G. J., Borriello, F., Hodes, R. J., Reiser, H., Gribben, J. G., Ng, J. W., Kim, J., Goldberg J. M., Hathcock, K., Laszlo, G., Lombard, L. A., Wang, S., Gray, G. S., Nadler, L. M. and Sharpe, A. H. 1993. Murine B7-2, an alternative CTLA-4 counter-receptor that co-stimulates T cell proliferation and interleukin 2 production. J. Exp. Med. 178:2185.[Abstract]
-
Green, J. M., Noel, P. J., Sperling, A. L., Walunas, T. L., Gray, G. S., Bluestone, J. A. and Thompson, C. B. 1994. Absence of B7-dependent responses in CD28-deficient mice. Immunity 1:501.[ISI][Medline]
-
Perez, V., Parijs, L., Biuckians, A., Zheng, X., Strom, T. and Abbas, A. 1997. Induction of peripheral T cell tolerance in vivo requires CTLA-4 engagement. Immunity. 6:411.[ISI][Medline]
-
Walunas, T. L. and Bluestone, J. A. 1999. CTLA-4 regulates tolerance induction and T cell differentiation in vivo. J. Immunol. 160:3855.[Abstract/Free Full Text]
-
Samoliova, E. B., Horton, J. L., Zhang, H., Khoury, S. J., Weiner, H. L. and Chen. Y. 1998. CTLA-4 is required for the induction of high dose oral tolerance. Int. Immunol. 10:491.[Abstract]
-
Issazadeh, S., Zhang, M., Sayegh, M. H. and Khoury, S. J. 1999. Acquired thymic tolerance: role of CTLA-4 in the initiation and maintenance of tolerance in a clinically relevant autoimmune disease model. J. Immunol. 162:761.[Abstract/Free Full Text]
-
Martin, R., McFarland, H. F. and McFarlin, D. E. 1992. Immunological aspects of demyelinating diseases. Annu. Rev. Immunol. 10:153.[ISI][Medline]
-
Zamvil, S. S. and Steinman, L. 1990. The lymphocyte in experimental allergic encephalomyelitis. Annu. Rev. Immunol. 8:579.[ISI][Medline]
-
Murphy, E. E., Terres, G., Macatonia, S. E., Hsieh, C. S., Mattson, J., Lanier, L., Wysocka, M., Trinchieri, G., Murphy, K. and O'Garra, A. 1994. B7 and interleukin 12 cooperate for proliferation and interferon gamma production by mouse T helper clones that are unresponsive to B7 co-stimulation. J. Exp. Med. 180:223.[Abstract]
-
Gimmi, C. D., Freeman, G. J., Gribben, J. G., Gray, G. and Nadler, L. M. 1993. Human T cell clonal anergy is induced by antigen presentation in the absence of B7 co-stimulation. Proc. Natl Acad. Sci. USA 90:6586.[Abstract]
-
Perrin, P. J., Scott, D., Quigley, L., Albert, P. S., Feder, O., Gray, G. S., Abe, R., June, C. H. and Racke, M. K. 1995. The role of B7:CD28/CTLA-4 in the induction of chronic relapsing experimental allergic encephalomyelitis. J. Immunol. 154:1481.[Abstract/Free Full Text]
-
Racke, M. K., Scott, D. E., Quigley, L., Gray, G. S., Abe, R., June, C. H. and Perrin, P. J. 1995. Distinct roles for B7-1 (CD80) and B7-2 (CD86) in the initiation of experimental allergic encephalomyelitis. J. Clin. Invest. 96:2195.[ISI][Medline]
-
Critchfield, J. M., Racke, M. K., Zuniga-Pflucker, J. C., Cannella, B., Raine, C. S., Goverman, J. and Lenardo, M. J. 1994. T cell deletion in high antigen dose therapy of autoimmune encephalomyelitis. Science 263:1139.[ISI][Medline]
-
Racke, M. K., Critchfield, J. M., Quigley, L., Cannella, B., Raine, C. S., McFarland, H. F. and Lenardo, M. J. 1996. Intravenous antigen administration as a therapy for autoimmune demyelinating disease. Ann. Neurol. 39:46.[ISI][Medline]
-
Goverman, J., Woods, A., Larson, L., Weiner, L. P., Hood, L. and Zaller, D. M. 1993. Transgenic mice that express a myelin basic protein-specific T cell receptor develop spontaneous autoimmunity. Cell 72:551.[ISI][Medline]
-
Buenafe, A. C., Tsu, R. C., Bebo, B., Vandenbark, A. A. and Offner, H. 1997. Myelin basic protein-specific and TCR Vß8.2-specific T cell lines from TCR Vß8.2 transgenic mice utilize the same V
and Vß genes: specificity associated with the V
CDR3J
region. J. Neurosci. Res. 47:489.[ISI][Medline]
-
Siklodi, B., Jacobs, R., Vandenbark, A. A. and Offner, H. 1998. Neonatal exposure of TCR BV8S2 transgenic mice to recombinant TCR BV8S2 results in reduced T cell proliferation and elevated antibody response to BV8S2, and increased severity of EAE. J. Neurosci. Res. 52:750.[ISI][Medline]
-
Deibler, G. E., Martenson, R. E. and Kies, M. W. 1972. Large scale preparation of myelin basic protein from central nervous system tissue of several mammalian species. Prep. Biochem. 2:139.[ISI][Medline]
-
Walunas, T. L., Lenschow, D. J., Bakker, C. Y., Linsley, P. S., Freeman, G. J., Green, J. M., Thompson, C. B. and Bluestone, J. A. 1994. CTLA-4 can function as a negative regulator of T cell activation. Immunity. 1:405.[ISI][Medline]
-
Yoshimoto, T. and Paul, W. E. 1994. CD4 pos, NK1.1 pos T cells promptly produce interleukin 4 in response to in vivo challenge with anti-CD3. J. Exp. Med. 179:1285.[Abstract]
-
Racke, M. K., Bonomo, A., Scott, D. E., Cannella, B., Levine, A., Raine, C. S., Shevach, E. M. and Rocken, M. 1994. Cytokine-induced immune deviation as a therapy for inflammatory autoimmune disease. J. Exp. Med. 180:1961.[Abstract]
-
Ratts, R. B., Arredondo, L. R., Bittner, P., Perrin, P. J., Lovett-Racke, A. E. and Racke, M. K. (1999) The role of CTLA-4 in tolerance induction and T cell differentiation in experimental autoimmune encephalomyelitis: i.p. antigen administration. Int. Immunol. 11:1881.[Abstract/Free Full Text]
-
Parijs, L. V., Perez, V. L., Biuckians, A., Maki, R. G., London, C. A. and Abbas, A. K. 1997. Role of interleukin 12 and co-stimulators in T cell anergy in vivo. J. Exp. Med. 186:1119.[Abstract/Free Full Text]
-
Ceredig, R. and Corradin, G. 1986. High antigen concentration inhibits T cell proliferation but not IL-2 production: examination of limiting dilution microcultures and T cell clones. Eur. J. Immunol. 16:30.[ISI][Medline]
-
Malvey, E. N., Jenkins, M. K. and Mueller, D. L. 1998. Peripheral immune tolerance blocks clonal expansion but fails to prevent differentiation of Th1 cells. J. Immunol. 161:2168.[Abstract/Free Full Text]