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At least 19 recordsLinked to original sources
PubMed1990

The influence of MHC and non-MHC genes on the nature of murine cardiac allograft rejection. I. Kinetic analysis of mononuclear cell infiltrate and MHC-class I/class II expression in donor tissue.

While normal cardiac tissue expresses low levels of MHC-class I, undetectable levels of MHC-class II antigens, and no mononuclear cell infiltrates, posttransplantation allogeneic donor cardiac tissue demonstrates dramatic increases of MHC-class I/class II expression coincident with the infiltration of the tissue with mononuclear cells. Results of this study demonstrate that the kinetics of MHC-class I/II antigen expression and the phenotype of mononuclear cell infiltrate are influenced, to a great degree, by the genetic H-2, intra-H-2 and non-H-2 incompatibility between donor and recipient strains of mice. Increases of MHC-class I precede class II expression in cells from donor cardiac tissue from completely allogeneic BALB/c, H-2-disparate B10.D2, B10.BR, and K, I-A and I-E-disparate B10.T (6R) strains of mice implanted in B10 recipients. In contrast, increase in the level of MHC-class II precedes MHC-class I increases in donor cardiac tissue from H-2-identical but non-H-2-incompatible A. By and the I-E + H-2D end-different B10.A(5R) donor tissue. The completely allogeneic, H-2-disparate or K, I-A, I-E-disparate donor cardiac tissue induced the infiltration of predominantly CD8+ T cells, whereas the non H-2 and I-E + H-2D end-different donor cardiac tissue induced the infiltration of predominantly CD4+ T cells. Finally, whereas bm1 donor cardiac tissue is rejected by B6 recipients by day 32, the (bm1 x bm12)F1 allografts are rejected by day 20, and both express MHC-class I antigens followed by MHC-class II antigens, and contain predominantly CD8+ T cells. In contrast, bm12 allografts are not rejected by B6 recipients, express chronic low levels of both MHC-class I and II antigens, and contain predominantly CD4+ T cells. Of interest is our preliminary finding that bm12 allografts placed in one ear of B6 recipients appear to modify the kinetics of MHC antigen expression and the predominant phenotype of mononuclear cell infiltrates in bm1 allografts placed in the opposite ear. Cumulatively, these data suggest that the type of genetic disparity between cardiac donor and recipient greatly influences the quantitative and qualitative host responses.

Animals↗
PubMed1991

Some cloned murine CD4+ T cells recognize H-2Ld class I MHC determinants directly. Other cloned CD4+ T cells recognize H-2Ld class I MHC determinants in the context of class II MHC molecules.

Murine T lymphocytes recognize nominal Ag presented by class I or class II MHC molecules. Most CD8+ T cells recognize Ag presented in the context of class I molecules, whereas most CD4+ cells recognize Ag associated with class II molecules. However, it has been shown that a proportion of T cells recognizing class I alloantigens express CD4 surface molecules. Furthermore, CD4+ T cells are sufficient for the rejection of H-2Kbm10 and H-2Kbm11 class I disparate skin grafts. It has been suggested that the CD4 component of an anti-class I response can be ascribed to T cells recognizing class I determinants in the context of class II MHC products. To examine the specificity and effector functions of class I-specific HTL, CD4+ T cells were stimulated with APC that differed from them at a class I locus. Specifically, a MLC was prepared involving an allogeneic difference only at the Ld region. CD4+ clones were derived by limiting dilution of bulk MLC cells. Two clones have been studied in detail. The CD4+ clone 46.2 produced IL-2, IL-3, and IFN-gamma when stimulated with anti-CD3 mAb, whereas the CD4+ clone 93.1 secreted IL-4 in addition to IL-2, IL-3, and IFN-gamma. Cloned 46.2 cells recognized H-2Ld directly, whereas recognition of Ld by 93.1 apparently was restricted by class II MHC molecules. Furthermore, cytolysis by both clones 46.2 and 93.1 was inhibited by the anti-CD4 mAb GK1.5. These results demonstrate that CD4+ T cells can respond to a class I difference and that a proportion of CD4+ T cells can recognize class I MHC determinants directly as well as in the context of class II MHC molecules.

Animals↗
PubMed1989

The influence of MHC-compatible and MHC-incompatible antigen-presenting cells on the survival of MHC-compatible cultured murine keratinocyte allografts.

Our group has shown previously that APC-depleted cultured epidermal keratinocytes show prolonged survival when grafted onto normal MHC-incompatible adult mice. We show here that in vitro culture also improves significantly the survival of MHC-compatible keratinocyte allografts, although these nonrejected grafts are repopulated by host cells identified by their dendritic morphology and phenotype (class II+, leukocyte-common antigen+) as APCs. Reconstitution of cultured grafts, immediately prior to transplantation, with MHC-compatible dendritic cells of either donor or recipient origin, results in graft rejection--thus demonstrating that cultured cells can be rejected by the recipient animal--and suggests that a paucity of APCs in the immediate postgrafting period is responsible for the privilege afforded these grafts.

Animals↗
PubMed1986

Cooperation between cytotoxic and helper T lymphocytes in protection against lethal Sendai virus infection. Protection by T cells is MHC-restricted and MHC-regulated; a model for MHC-disease associations.

The in vivo importance of class I MHC regulation of the Tc response to a natural pathogenic agent of high virulence was studied on the basis of our previous demonstration of a major difference in the capacity to generate a Sendai virus-specific Tc response between C57BL/6 (B6, H-2b) mice and H-2Kb mutant B6.C-H-2bm1 (bm 1) mice. These two mouse strains differ from each other only in three amino acids in the crucial H-2Kb restriction element for this response. bm 1 mice, in contrast to B6 mice, are Tc nonresponders against this virus, but show Sendai-specific T cell proliferation, antibody production, and DTH reactions, as well as NK cell activity, equal to those of B6 mice. B6, Sendai Tc-deficient bm 1 and T cell-deficient B6 nu/nu mice differ from each other in susceptibility to lethal pneumonia induced by i.n. inoculation of virulent Sendai virus. The lethal dose (LD50) in B6 mice averaged 152 TCID50, in bm 1 mice, 14 TCID50 and in B6 nu/nu mice 0.5 TCID50. The importance of Tc was also shown by the complete protection of B6 nu/nu mice against infection with a lethal virus dose by i.v. injection of a Sendai virus-specific, IL-2-dependent and H-2Kb-restricted B6 Tc clone. In vivo protection by this Tc clone was H-2Kb-restricted. Apart from Tc, an important role for virus-specific Th cells is evident from the difference in susceptibility between bm 1 and B6 nu/nu mice. This conclusion was supported by the demonstration that the mean survival time of B6 nu/nu and bm 1 nu/nu mice could be significantly prolonged, in an I-Ab-restricted manner, by the injection of in vitro-propagated, Sendai-specific B6 or bm 1 Th clones after a lethal dose of Sendai virus, and by the demonstration that inoculation of these Th clones provided help to virus-specific Tc by means of IL-2 production. Strikingly, Th and Tc cooperate in anti-Sendai virus immunity, since permanent survival of lethally infected nu/nu mice was only achieved by inoculation of a mixture of Tc and Th clones or a mixture of a Tc clone and rIL-2. This study provides a unique model for the study of MHC-disease associations.

Animals↗
PubMed1989

Schwann cells co-cultured with stimulated T cells and antigen express major histocompatibility complex (MHC) class II determinants without interferon-gamma pretreatment: synergistic effects of interferon-gamma and tumor necrosis factor on MHC class II induction.

Schwann cells (SC) do not express major histocompatibility complex (MHC) class II antigens under normal culture conditions. SC can, however, be induced in vitro to express MHC class II molecules by exposure to high concentrations of interferon-gamma (IFN-gamma) and can present antigens to antigen-specific T cell lines. In the present study immunohistochemical labeling showed that most SC (greater than 90%) prepared from rat neonatal sciatic nerves expressed MHC class II molecules when cultured together with mycobacterial antigen and T cells, and as a consequence were able to function as antigen-presenting cells in lymphoproliferation assays, without requiring pretreatment with IFN-gamma. Antigen or T cells alone were ineffective in stimulating MHC class II expression and induction of class II molecules was MHC restricted, requiring the presence of syngeneic T cells. Addition of monoclonal antibody DB1, directed against IFN-gamma to co-cultures of SC and T lymphocytes stimulated with antigen, prevented the induction of MHC class II antigen on SC. When SC were incubated with recombinant (r)IFN-gamma alone, up to 50% of SC showed positive labeling for MHC class II antigen. This level of expression was enhanced to greater than 80% when recombinant tumor necrosis factor (rTNF) was also added. rTNF alone had no effect, and addition of DBI antibody inhibited the synergistic effects of rTNF on MHC class II expression. The effects of rIL 4 were also investigated but neither rIL 4 alone nor rIL 4 in combination with rIFN-gamma induced MHC class II expression by SC. These results show that in the presence of sensitized T lymphocytes and antigen, SC do not require pretreatment with exogenous rIFN-gamma to express MHC class II antigens and function as antigen-presenting cells. T cell-derived TNF and IFN-gamma appear to act as mediators of the T cell-induced expression of MHC class II by SC.

Animals↗
PubMed1988

Modulation of major histocompatibility complex (MHC) expression by interferons and microbial agents. Independent regulation of MHC class II expression and induction of tumoricidal activity in bone marrow-derived mononuclear phagocytes.

In a pure population of rat bone marrow-derived mononuclear phagocytes (BMM phi), the expression of major histocompatibility complex (MHC) molecules and ability to manifest tumoricidal activity were simultaneously studied. Resting BMM phi, which express low levels of MHC class II molecules and do not manifest tumoricidal activity, become strongly MHC class II-positive, and evolve tumoricidal activity within 24 h when incubated with macrophage-activating lymphokines (MAF) or gamma interferon (IFN-gamma). In contrast, BMM phi which were interacted for 24 h with heat-killed microbial agents (Corynebacterium parvum, Listeria) evolve tumoricidal activity without parallel enhancement of MHC class II expression. IFN-alpha,beta neither induced tumoricidal activity nor enhanced MHC class II expression. Further experiments have shown that (a) the kinetics of MAF- and/or IFN-gamma-induced amplification of MHC class II expression and of tumoricidal activity are different; (b) enhancement of MHC class II expression by rIFN-gamma is not invariably paralleled by induction of tumoricidal activity; and (c) inhibitors of macrophage tumoricidal activity differ in their ability to affect MHC class II expression. It is concluded from these findings that in a population of pure BMM phi, i.e. in the complete absence of lymphocytes, the expression of MHC molecules and induction of tumoricidal activity are independently regulated phenomena; in particular, the enhanced expression of MHC class II molecules is not a prerequisite for induction and/or manifestation of tumoricidal activity by mononuclear phagocytes.

Adjuvants, Immunologic↗
PubMed1990

Differential expression of CD8 alpha and CD8 beta associated with MHC-restricted and non-MHC-restricted cytolytic effector cells.

The differential expression of the alpha and beta chains of the CD8 glycoprotein was examined in three functionally distinct cytolytic effector cell populations: (i) T cells (CD3+ CD56-), (ii) NK cells (CD56+ CD3-), and (iii) non-MHC-restricted T cells (CD56+ CD3+). Twenty-four percent of T cells were CD8+, and they consistently coexpressed both CD8 alpha and CD8 beta. Moreover, CD8+ T cells uniformly expressed high-density CD8 alpha. Forty percent of NK cells were CD8+ but the vast majority (approximately 75%) expressed only CD8 alpha without CD8 beta. In addition, CD8+ NK cells uniformly expressed low-density CD8 alpha. In comparison, 75% of non-MHC-restricted T lymphocytes were CD8+ but they displayed an intermediate phenotype: 60% coexpressed CD8 alpha and CD8 beta while 40% expressed only CD8 alpha. Within this population, CD8 alpha was expressed at high density, similar to that of T cells. Following IL-2 activation, enhancement of non-MHC-restricted cytotoxicity was not associated with any changes in either the quantitative or qualitative pattern of expression of CD8 alpha or CD8 beta by these cells. Addition of either anti-CD8 alpha or anti-CD8 beta mAb did not alter non-MHC-restricted cytotoxicity of either CD56+ CD3- or CD56+ CD3+ effector cells. However, within the CD56+ cell population, non-MHC-restricted cytotoxicity was almost entirely found within the CD8- and CD8 alpha + beta- populations, and both subsets displayed a similar level of killing. In contrast, CD8 alpha+ beta+ cells exhibited very little non-MHC-restricted cytotoxicity. Thus, the coexpression of CD8 alpha and CD8 beta in conjunction with the TCR/CD3 complex appears to characterize MHC restricted cells while the expression of CD8 alpha alone is associated with non-MHC-restricted cytotoxicity. Taken together, these findings suggest that neither CD8 alpha nor CD8 beta is involved in the initial phases of target cell binding or recognition during NK cell-mediated lysis. However, the selective expression of CD8 alpha by a large fraction of non-MHC-restricted effector cells suggests that this antigen may play a different functional role in this unique subset of cytolytic lymphocytes.

Antibodies, Monoclonal↗
PubMed1989

Selective decreases in T cell receptor V beta expression. Decreased expression of specific V beta families is associated with expression of multiple MHC and non-MHC gene products.

Previous reports of TCR V beta usage, studying either expression of a single V beta in a wide panel of strains (6, 7, 10, 12, 13), or expression of multiple V beta s in a very limited strain distribution (14, 15), have identified instances of clonal deletion of potentially autoreactive T cells specific for either self E alpha E beta or minor lymphocyte stimulatory (Mls) antigens. The present study has investigated the range of self antigens that can influence V beta usage by evaluating expression of 16 V beta families in 30 strains of mice. It was found that significant decreases in expression occur in at least 8 of the 16 V beta families and that dominant influences on the T cell V beta repertoire are exerted by expression of Mlsa, Mlsc, and MHC gene products. Decreased expressions of V beta 5, -11, -12, and -16 were influenced by MHC gene products. The patterns of decreased expression seen in intra-MHC recombinant strains and strains of different non-MHC background were distinct for V beta 11, -12, and -16, suggesting that different ligands are involved in the deletion of T cells expressing each of these V beta genes. Mice expressing Mlsa show decreased expression of V beta 9 as well as V beta 6. Mlsc mice lacked V beta 3 expression in those strains where the expressed MHC type was compatible with a strongly stimulatory Mlsc phenotype. V beta 7 was strongly influenced by both MHC and non-MHC products that are not yet identified. These results demonstrate that strain-specific decreases of mRNA expression occur in a major portion of the TCR repertoire. Self antigens including Mlsa, Mlsc, and E alpha E beta, as well as additional MHC and non-MHC products, appear to induce these decreases in expression in the process of eliminating self-reactive T cells from the mature T cell pool.

Animals↗
PubMed1988

Genetic analysis of the presentation of minor lymphocyte stimulating determinants. I. Combined importance of MHC and non-MHC influences.

In the course of studying the MHC restriction of minor lymphocyte stimulating (Mls) determinants, we observed that variation in the ability to present Mlsc determinants occurred with stimulator cells from different mouse strains that express the same class II MHC restricting elements; for example, one Iad-bearing strain, C3H.HTG, presented this non-MHC moiety, whereas another, C3H.OH, could not. As another example, the prototype Mlsb nonstimulatory H-2d stimulator cell, BALB/c, was shown to encode Mlsc even though it failed to trigger proliferation across this non-MHC barrier. In contrast, H-2d-compatible DBA/2 stimulator cells were capable of eliciting detectable levels of unprimed responder T cell proliferation across an Mlsc difference. Even when the BALB/c H-2d haplotype was replaced with the fully permissive H-2K halplotype, these BALB.K stimulator cells presented Mlsc (but not MHC) less effectively than H-2K-compatible C3H/HeJ stimulator cells. Analysis of the Mlsc-presenting capacity of stimulator cells obtained from (BALB.K x C3H) F1 x BALB.K first backcross and (BALB.K x C3H)F2 animals indicated that non-MHC-control influencing stimulatory ability of this non-H-2 Ag was multigenic. In addition, the capacity of DBA/2 to present Mlsa determinants more effectively than MHC-identical LT/ChReSv stimulator cells may indicate that the presentation of this Mls specificity is also influenced by non-MHC Ir genes. Thus the Mls phenotype of an animal should be considered the combined result of an Mls structural gene, the MHC haplotype, and multiple non-H-2 regulatory influences.

Animals↗
PubMed1989

The combination of major histocompatibility complex (MHC) and non-MHC genes influences murine lymphocytic choriomeningitis virus pathogenesis.

Resistance to the acute lethal disease caused by the docile strain of lymphocytic choriomeningitis (LCM) virus varies widely between different mouse strains. In order to study the inheritance of host influence on susceptibility to this strain of LCM virus, we crossed the F1 to the parent with the recessive disease phenotype. In all cases, susceptibility was dominant. In backcross progeny obtained from matings of parental strains differing in both major histocompatibility complex (MHC) and non-MHC (SWR; C3H), 90% of the challenged mice died, indicating that at least three loci controlled susceptibility to the disease. When the parental strains carried similar MHC haplotypes but dissimilar background genes (B10.BR; CBA), 78% of the backcross mice succumbed, indicating that at least two non-MHC loci influenced disease susceptibility. It is unlikely, however, that the same two non-MHC loci are critical in all genetic combinations, since F1 produced from two H-2 identical, resistant strains (B10.BR; C3H) were found to be fully susceptible. When congenic mice, differing only in the D-end of the MHC region, were analysed, 50% of the backcross animals died, indicating that one gene in the MHC region was important; segregation analysis comparing MHC serotype and disease outcome indicated the H-2D locus itself as the determining factor.

Animals↗
PubMed1990

A single recessive non-MHC diabetogenic gene determines the development of insulitis in the presence of an MHC-linked diabetogenic gene in NOD mice.

To study the genetic control of insulitis in non-obese diabetic (NOD) mice, we performed breeding studies in crosses of NOD with non-diabetic strains, ICR-L-line Ishibe (ILI), non-obese non-diabetic (NON) and C3H/He mice. The ILI mouse serologically shared the same MHC Class I and Class II as the NOD mouse. Insulitis was defined as islets invaded by lymphoid cells. Periductular, perivascular and peri-insular lymphoid cell infiltrations were often observed in NOD mice and appear to be the initial lesion leading to insulitis. Such lesions, however, were found in 1-year-old ICR, ILI, NON and Cataract Shionogi (CTS) mice of the NOD's sister strain. The lymphoid cells did not invade the islets in ICR, ILI, NON and CTS mice. The incidence of insulitis was 0% in F1 generations and 40% in female backcrosses (BC) [(ILI x NOD)F1 x NOD] at 9 weeks of age, 48 and 50% in BC[(NON x NOD)F1 x NOD] and BC[(C3H/He x NOD)F1 x NOD] at 1 year of age, respectively. Backcross animals were typed for the MHC to investigate correlation between the development of insulitis and MHC haplotypes. Among the backcross females with insulitis, approximately half the animals were heterozygous for MHC(non/nod) in BC[(NON x NOD)F1 x NOD] and MHC(k/nod) in BC[(C3H x NOD)F1 x NOD]. Among the backcross females with no insulitis, approximately half the animals were homozygous for MHC(nod/nod) in BC[(NON x NOD)F1 x NOD] and in BC[(C3H x NOD)F1 x NOD]. The results suggest that a single recessive non-MHC diabetogenic gene determines the development of insulitis regardless of NOD MHC homozygosity or heterozygosity.

Animals↗
PubMed2026

Identification of MHC Ligands Through Allele-Guided Isolation Combined With Machine Learning for Improved MHC Assignment Using ARDisplay-I.

The isolation of major histocompatibility complex (MHC) ligands and subsequent analysis by mass spectrometry is considered the gold standard for defining targets for T cell-based immunotherapies. However, as many targets of high tumor specificity are only presented at low abundance on the cell surface of tumor cells, the efficient isolation of these peptides is crucial for their successful detection. Here, we demonstrate how optimizing the MHC ligand isolation strategy, based on both the presenting MHC alleles and the individual peptide level, enhances the identification of specific MHC ligands. This ideally acknowledges not only the hydrophobicity but also the post-translational modifications of the respective MHC ligands. To further improve the identification and characterization of MHC ligands, we developed an MHC class I ligand prediction algorithm (ARDisplay-I) that outperforms current state-of-the-art tools when benchmarked against competitors such as netMHCpan 4.1, MixMHCpred, or MHCflurry. Implementing these strategies can augment the development of T cell receptor-based therapies by improving the identification of novel immunotherapy targets and enriching the resources available in the computational immunology field through a superior MHC presentation prediction algorithm.

Ligands↗
PubMed1992

Autoimmune syndromes in major histocompatibility complex (MHC) congenic strains of nonobese diabetic (NOD) mice. The NOD MHC is dominant for insulitis and cyclophosphamide-induced diabetes.

The development of autoimmune diabetes in the nonobese diabetic (NOD) mouse is controlled by multiple genes. At least one diabetogenic gene is linked to the major histocompatibility complex (MHC) of the NOD and is most likely represented by the two genes encoding the alpha and beta chains of the unique NOD class II molecule. Three other diabetogenic loci have recently been identified in the NOD mouse and are located on chromosomes 1, 3, and 11. In addition to the autoimmune diabetes which is caused by destruction of the insulin-producing beta cells in the pancreas, other manifestations of autoimmunity are seen in the NOD mouse. These include mononuclear cell inflammation of the submandibular and lacrimal glands, as well as the presence of circulating autoantibodies. To determine the effect of the non-MHC diabetogenic genes on the development of autoimmunity, we constructed the NOD.B10-H-2b (NOD.H-2b) strain, which possesses the non-MHC diabetogenic genes from the NOD mouse, but derives its MHC from the C57BL/10 (B10) strain. The NOD.H-2b strain does not develop insulitis, cyclophosphamide-induced diabetes, or spontaneous diabetes. It does, however, develop extensive lymphocytic infiltrates in the pancreas and the submandibular glands that are primarily composed of Thy 1.2+ T cells and B220+ B cells. In addition, autoantibodies are present in NOD.H-2b mice which recognize the "polar antigen" on the insulin-secreting rat tumor line RINm38. These observations demonstrate that the non-MHC genes in the NOD strain, in the absence of the NOD MHC, significantly contribute to the development of autoimmunity. The contribution of a single dose of the NOD MHC to autoimmunity was assessed with a (NOD x NOD.H-2b)F1 cross. Although only approximately 3% of F1 females developed spontaneous diabetes, approximately 50% of both female and male F1 mice developed insulitis, and 25% of females and 17% of males became diabetic after treatment with cyclophosphamide. These data demonstrate that the MHC-linked diabetogenic genes of the NOD mouse are dominant with decreasing levels of penetrance for the following phenotypes: insulitis greater than cyclophosphamide-induced diabetes greater than spontaneous diabetes.

Animals↗
PubMed1990

Lymphocyte-mediated activation of cultured endothelial cells (EC). CD4+ T cells inhibit EC class II MHC expression despite secreting IFN-gamma and increasing EC class I MHC and intercellular adhesion molecule-1 expression.

Endothelial cells (EC) were cocultured with allogeneic PBL, CD4+ T cells, or CD8+ T cells, and the degrees of EC activation induced examined by determining patterns of endothelial class I and class II MHC and intercellular adhesion molecule-1 (ICAM-1) expression. Coculture with PBL or CD8+ T cells uniformly increases class I MHC and ICAM-1 expression on all EC within a culture, but induces class II MHC expression on only a subpopulation(s) of EC. This heterogeneous EC response to coculture contrasts with the uniform class II expression on all EC induced by IFN-gamma in replicate wells. CD4+ T cells, when compared to equal numbers of unfractionated PBL or CD8+ T cells, are more effective at increasing class I MHC and ICAM-1 but are unable to induce class II MHC expression. The failure of CD4+ T cells to induce EC class II MHC Ag is not due to insufficient activation of the T cells, as PHA-activated CD4+ T cells also do not induce significant class II expression. In addition, conditioned media (CM) from CD4+ T cell/EC contain greater levels of immunoreactive IFN-gamma than do CM from PBL/EC cocultures. Rather, CD4+ T cells appear to actively inhibit the induction of EC class II Ag but not class I or ICAM-1 by IFN-gamma. Inhibition occurs at the time of induction, as CD4+ T cells are not capable of down-regulating previously induced class II Ag. CM from CD4+/EC (but not PBL/EC) cocultures also inhibits IFN-gamma induction of EC class II MHC expression. The inhibitory activity is generated during CD4+ T cell-EC cell contact, and is enhanced by PHA. The inhibitory activity(ies) of the CD4+/EC-CM is as yet unidentified, and is only minimally reversible by cocktails of neutralizing antibodies directed against TNF-alpha, TNF-beta (lymphotoxin), IFN-alpha and IFN-beta. In conclusion, CD4+ and CD8+ T cells are each effective activators of EC, but the patterns of activation produced by these subsets are quite distinct, largely due to generation of a soluble inhibitor(s) of class II MHC induction during coculture of CD4+ T cells with EC.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1989

Asymmetry in the recognition of antigen: self class II MHC and non-self class II MHC molecules by the same T-cell receptor.

One of the most puzzling observations in immunology is the very high frequency of T cells reactive to non-self MHC molecules. Earlier studies from our laboratory suggested that the same receptor on a cloned T-cell line recognized both self-class II MHC: antigen complexes and non-self class II MHC, the latter at a significantly lower affinity. This suggested that alloreactivity resulted from low affinity cross-reactions of the T-cell receptor to a ligand presented at high multiplicity. The present studies address the question of whether these two ligands are recognized symmetrically by this receptor, and of whether different subsites in the receptor recognize both classes of ligands equally. In the present studies, we have greatly extended our analysis of T-cell receptor recognition of antigen: self class II MHC and non-self class II MHC. Using Fab fragments of monoclonal anti-T-cell receptor antibodies as monovalent competitive antagonists of T-cell activation, the response of cloned H-2k T-cell line D10 to conalbumin: I-Ak and to the allogeneic ligands I-Ab,v,p,q was analyzed with monoclonal antibodies directed at 3 clonotypic epitopes and one on V beta. These studies confirmed our earlier finding that D10 activation by antigen: self class II MHC is more difficult to inhibit with clonotypic Fab fragments binding to three distinct clonotypic epitopes than are responses to non-self MHC. More importantly, the Fab fragment of anti-V beta monoclonal antibodies preferentially inhibit activation by antigen: self class II MHC, and do so more efficiently than expected, based on the numbers of molecules of Fab bound.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

Tumor-specific immunity can be enhanced by transfection of tumor cells with syngeneic MHC-class-II genes or allogeneic MHC-class-I genes.

Mouse Sal sarcoma cells are lethal in the autologous A/J (KkDd) host. In order to improve the immune response to the Sal tumor, Sal cells have been transfected with syngeneic MHC-class-II or allogeneic MHC-class-I genes. MHC-class-II transfectants are uniformly rejected by the autologous host and immunization with them protects against subsequent Sal challenge. The improved immunity is probably the result of enhanced generation of tumor-specific Th cells. We hypothesize that class-II tumor cells trigger an improved Th-cell response because they directly present Sal tumor antigens in the context of class-II molecules to Th cells, by-passing professional APC. Studies by others have demonstrated that antigen presentation requires an intracellular signal transmitted by the cytoplasmic domain of the APC class-II molecule. Sal cells expressing class-II antigens with truncated cytoplasmic domains are as malignant as wild-type Sal cells. These experiments therefore support the role of tumor-cell class-II molecules as antigen presentation elements, and demonstrate the requirement for intact class-II molecules for tumor protection. Sal cells have also been transfected with allogeneic MHC-class-I genes. Although Kb-transfected cells are not rejected by A/J mice, Db-transfected Sal cells and Kb- plus Db-transfected cells are rejected. The Db transfectants effectively immunize A/J mice against subsequent Sal challenge. These experiments demonstrate that expression of certain allogeneic MHC-class-I genes can lead to tumor-specific immunity, and that such transfectants can protect against challenges of wild-type tumor cells. Transfection of tumor cells with syngeneic MHC-class-II or allogeneic MHC-class-I genes may therefore be a potential strategy for improving tumor-specific immunity in the autologous host.

Animals↗
PubMed1991

Regulation of experimental autoimmune uveitis in rats--separation of MHC and non-MHC gene effects.

Experimental autoimmune uveitis (EAU) is an organ-specific autoimmune disease and has served as a model of certain ocular inflammatory conditions in man. The present study was aimed at separating the effects of MHC and non-MHC genes on the development of EAU in the rat. EAU-susceptible LEW (RT1l), EAU-resistant WKAH (RT1k), and WKAH.1L (RT1l) MHC congenic strain of WKAH background rats were immunized with retinal soluble antigen (S-Ag) in Freund's complete adjuvant (FCA). LEW rats showed typical EAU, while neither WKAH nor WKAH.1L congenic rats developed EAU. However, when an additional i.v. injection of Bordetella pertussis was given, all rat strains developed EAU. Furthermore, when immunized with peptide M, an 18-mer synthetic peptide, which corresponds to amino acid positions 303-320 of bovine S-Ag, and given an additional i.v. injection of B. pertussis, LEW and WKAH.1L rats developed EAU, whereas WKAH did not. When ACI (RT1avl), BUF (RT1b), LEJ (RT1j), W (RT1k), F344 (RT1lvl), BN (RT1n), NIG-III (RT1q), TO (RT1t), and SDJ (RT1u) rats were immunized with peptide M or S-Ag and then B. pertussis, all strains developed EAU by immunization with S-Ag plus B. pertussis, but only F344 and NIG-III developed EAU by immunization with peptide M. These findings suggest that susceptibility to EAU in rats is controlled by both MHC and non-MHC genes; and that in the absence of B. pertussis adjuvant, the form of disease induced by native S-Ag in FCA is governed by non-MHC gene(s). However, this effect of non-MHC gene(s) could no longer be observed when the rats were also injected with B. pertussis adjuvant at sensitization.

Amino Acid Sequence↗
PubMed1989

Genetic control of rat heart allograft rejection: effect of different MHC and non-MHC incompatibilities.

We investigated the genetic control of heterotopic heart allograft rejection using a family of standard inbred, major histocompatibility complex (MHC)-congenic, and intra-MHC recombinant rat strains. Gene products of the various regions within the rat MHC differed markedly in their capacity to induce rejection. Isolated incompatibility at class I antigens encoded by the RTl.A and RTl.C regions failed to induce rejection within the observation period of 100 days, whereas class II antigens encoded by the RTl.B/D region provoked rapid rejection within 10 days. By comparison of the rejection times of isolated and combined incompatibilities a number of functional interactions could be demonstrated between individual MHC regions which either prolonged or shortened allograft survival. In contrast to rapid rejection of MHC-mismatched heart allografts, differences at non-MHC histocompatibility antigens were associated with graft survival beyond 100 days, although chronic rejection of variable severity was detected histologically. Disparity at non-MHC plus class I antigens, however, provoked acute heart allograft rejection.

Animals↗