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Biomedical subjects

L Steinman

Publications and source records attributed to L Steinman.

At least 199 records · Page 11Linked to original sources
PubMed1989

Polymorphic residues on the I-A beta chain modulate the stimulation of T cell clones specific for the N-terminal peptide of the autoantigen myelin basic protein.

The effect of polymorphic residues on the A alpha A beta molecule on T cell recognition of the N-terminal nonapeptide of myelin basic protein (R1-9) was determined. Ak-restricted T cell clones recognizing R1-9 were isolated. The peptide-Ia specificities of these clones were determined by testing the response to 1) a panel of peptide analogs of R1-11, 2) splenic APC from mice expressing MHC molecules from serologically distinct haplotypes, and 3) L cell transfectants expressing mutant/recombinant A beta cDNA containing combinations of polymorphic nucleotide sequences from the k and u alleles. Comparisons were made between the Ak-restricted clones and a previously characterized panel of Au-restricted clones. Certain Ak-restricted clones were able to recognize MBP peptide analogs that were not recognized by any of the Au-restricted clones. The Au-restricted T cell clones did not cross-react with R1-9 presented in the context of Ak, whereas the majority of the Ak-restricted clones responded to R1-9 presented in the context of Au. This nonreciprocal cross-reactivity was also reflected in the relative responses of the two sets of T cell clones to the interchange of u- and k-derived residues in the A beta chain. Residues in regions corresponding both the alpha-helical or beta-sheet portions of the hypothetical Ia three-dimensional structure were involved. The results suggest that overall specificity of the T cell clones is the summation of numerous distinct subspecificities for different regions of the peptide-Ia ligand. These results indicate that there can be striking differences in T cell specificity for an autoantigenic epitope, even in the context of A alpha A beta molecules from very closely related haplotypes.

Amino Acid Sequence↗
PubMed1989

Comparison of rat and rat-mouse chimeric anti-murine CD4 antibodies in vitro. Chimeric antibodies lyse low-density CD4+ cells.

GK1.5, a rat anti-mouse CD4 mAb, is effective in the treatment of several autoimmune syndromes, induces tolerance to co-administered Ag, and prolongs allograft survival. We have constructed a family of molecules with GK1.5 V regions and mouse gamma 1, gamma 2a, gamma 2b, or gamma 3 constant regions to investigate the mechanisms underlying the effectiveness of GK1.5. The rat-mouse chimeric antibodies are specific for murine CD4 and have identical binding curves as rat GK1.5 on CD4+ T cells. The chimeric GK1.5 gamma 2a, GK1.5 gamma 2b, and GK1.5 gamma 3 antibodies are more efficient than rat GK1.5 at C-mediated cytotoxicity. This is attributed to the enhanced capacity of the chimeric antibodies, compared to rat GK1.5, to lyse CD4+ cells with a low cell surface Ag density. This observation may have important implications for therapy.

Animals↗
PubMed1989

Specific HLA-DQB and HLA-DRB1 alleles confer susceptibility to pemphigus vulgaris.

The autoimmune dermatologic disease pemphigus vulgaris (PV) is associated with the serotypes HLA-DR4 and HLA-DRw6. Based on nucleotide sequence and oligonucleotide probe analysis of enzymatically amplified DNA encoding HLA-DR beta chain (HLA-DRB) and HLA-DQ beta chain (HLA-DQB; henceforth HLA is omitted from designations), we showed previously that the DR4 susceptibility was associated with the Dw10 DRB1 allele [encoding the mixed lymphocyte culture (MLC)-defined Dw10 specificity]. The DRw6 susceptibility similarly was shown to be associated with a rare DQB allele (DQB1.3), which differed from another nonsusceptible allele by only a valine-to-aspartic acid substitution at position 57. Given the linkage disequilibrium that characterizes HLA haplotypes, it is difficult to assign disease susceptibility to a specific locus rather than to a closely linked gene(s) on the same haplotype. To address this problem, we have analyzed all of the polymorphic loci of the class II HLA region (DRB1, DRB3, DQA, DQB, and DPB) on the DRw6 haplotypes in patients and controls. In 22 PV patients, 4 different DRw6 haplotypes were found that encode the same DQ beta chain (DQB1.3) but contained silent nucleotide differences at the DQB locus as well as coding sequence differences in the DQA and DRB loci. These results, obtained by using a method for allele-specific polymerase chain reaction amplification, strongly support the hypothesis that the allele DQB1.3 confers susceptibility. This DQB allele is correlated with the MLC-defined Dw9 specificity and is associated with two different DRB1 alleles (the common "6A" associated with DRw13 and the rare "6B" associated with DRw14). Since 86% (19 of 22) of DRw6+ patients contain the DQB1.3 allele (vs. 3% of controls), whereas 64% (14 of 22) contain the DRB1 allele 6B (vs. 6% of the controls), we conclude that most of the DRw6 susceptibility to PV can be accounted for by the DQ beta chain.

Alleles↗
PubMed1989

Prevention of experimental encephalomyelitis with peptides that block interaction of T cells with major histocompatibility complex proteins.

Two synthetic immunodominant and nonencephalitogenic peptides of myelin basic protein, N1-20 and AcN9-20, effectively compete with an encephalitogenic peptide, AcN1-11, in an in vitro T-cell response restricted by class II major histocompatibility complex products (I-Au). These mutant peptide constructs, which do not occur in nature, also compete with the self-antigen for the in vivo induction of T cells primed with the encephalitogen AcN1-11. By using these nonpathogenic competitor peptides, it is possible to prevent the development of a prototypic T-cell-mediated autoimmune disease, experimental allergic encephalomyelitis. These results suggest possibilities for the utilization of competitor peptides for therapy of T-cell-mediated autoimmune diseases linked to specific major histocompatibility complex genes.

Amino Acid Sequence↗
PubMed1989

T-cell receptor V alpha and C alpha alleles associated with multiple and myasthenia gravis.

Polymorphic markers in genes encoding that alpha chain of the human T-cell receptor (TcR) have been detected by Southern blot analysis in Pss I digests. Polymorphic bands were observed at 6.3 and 2.0 kilobases (kb) with frequencies of 0.30 and 0.44, respectively, in the general population. Using the polymerase chain reaction (PCR) method, we amplified selected sequences derived from the full-length TcR alpha cDNA probe. These PCR products were used as specific probes to demonstrate that the 6.3-kb polymorphic fragment hybridizes to the variable (V)-region probe and the 2.0-kb fragment hybridizes to the constant (C)-region probe. Segregation of the polymorphic bands was analyzed in family studies. To look for associations between these markers and autoimmune diseases, we have studied the restriction fragment length polymorphism distribution of the Pss I markers in patients with multiple sclerosis, myasthenia gravis, and Graves disease. Significant differences in the frequency of the polymorphic V alpha and C alpha markers were identified between patients and healthy individuals.

Alleles↗
PubMed1989

T cell receptors in autoimmune disease as targets for immune intervention.

The optimal form of treatment for an autoimmune disease should be highly specific, have few side effects, and allow treatment of clinically apparent disease. One target that could fulfill these requirements is the T cell receptor. To answer the question whether treatment of autoimmune disease is possible with anti-T cell receptor antibodies, the heterogeneity of T cell receptor elements utilized in the T cell mediated autoimmune disease experimental allergic encephalomyelitis was analyzed. The limited heterogeneity of these elements allowed prevention and treatment of clinical autoimmune disease with anti-T cell receptor monoclonal antibodies. These results and their potential value for other autoimmune diseases are discussed.

Animals↗
PubMed1989

Cyclic adenosine 3',5'-monophosphate metabolism in activated T-cell clones.

The role of cAMP in lymphocyte proliferation was investigated in the response of a monoclonal T-cell population to a specific antigen and compared to the response to interleukin-2 (IL-2) and allogeneic cells. Myelin basic protein (MBP)-reactive and encephalitogenic T-cell clones were established from long-term lines derived from SJL/J (H-2s) mice. The clone 4b.14a recognizes the peptide sequence 89-101 of the MBP molecule in association with 1-As products of the major histocompatibility complex (MHC). Incubation of 4b.14a cells with syngeneic antigen-presenting cells, previously pulsed with the 89-101 synthetic peptide or with 80 U/ml of IL-2, or allogeneic H-2Ik cells, resulted in a significant increase in the accumulation of intracellular cAMP. This increase was preceded by a peak in membranal adenylate cyclase (AC) activity. Parallel time kinetics but significantly higher cAMP production and AC activity were observed when the cells were treated with pertussis toxin. At the same concentrations the toxin inhibits cellular proliferative responses, assayed by [3H]thymidine incorporation. Our results indicate the involvement of cAMP as a positive signal in the activation of the 4b.14a clone.

Animals↗
PubMed1989

Suppression of experimental uveitis in rats by anti-I-A antibodies.

I-region-associated (Ia) class II major histocompatibility complex (MHC) products are known to play a major role in autoimmunity. Effects of anti-I-A and anti-I-E monoclonal antibodies on development of experimental autoimmune uveitis (EAU) were investigated in Lewis rats. Prior to sensitization with S-antigen, seven groups of rats, six in each group, were injected intraperitoneally with one of the following agents. Groups 1, 2, and 3 (controls) received saline, RPMI and mouse immunoglobulin G (IgG), respectively. Groups 4 and 5 were injected with anti-I-E antibodies, 80 micrograms and 1000 micrograms, respectively. Similarly, groups 6 and 7 received anti-I-A, 100 micrograms and 750 micrograms, respectively. The treatments were repeated on days 1, 2, 5, 8, and 11 after S-antigen injection. All these animals were killed on day 18. In addition, two groups of rats sensitized with S-antigen were treated with 750 micrograms anti-I-A antibodies on days 5, 6, and 7 (group 8) and on days 7, 8 and 9 (group 9). An additional group (group 10) of Lewis rats was treated with 750 micrograms anti-I-A 1 day prior to and on days 1 and 2 after S-antigen injection. These group-10 animals were killed on day 31. Histopathologically, the enucleated globes of animals treated with high dose anti-I-A revealed marked suppression or inhibition of uveitis development. Such inhibition was virtually complete when the antibody was administered within a week of S-antigen injection, and the inhibitory effect lasted for at least 31 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

MHC-restricted recognition of immunogenic T cell epitopes of pertussis toxin reveals determinants in man distinct from the ADP-ribosylase active site.

The S1 subunit of Pertussis toxin (PT) is responsible for the reactogenicity and in part the immunogenicity of Bordetella pertussis vaccine. The critical residues associated with the immunomodulatory effects of PT were located around Glu140 in the S1 subunit. In man, T cell responses to PT are directed at S1 peptides distinct from Glu140. Two such epitopes, p64-75 and p151-161, are immunogenic in a panel of individuals covering a wide range of HLA genotypes. The response to PT peptides is HLA class II restricted. The response to p64-75 is blocked by an anti-HLA-DQ mAb, while that to p151-161 is blocked by an anti-HLA-DR mAb. These findings may allow for the development of a B. pertussis vaccine free from reactogenicity.

Amino Acid Sequence↗
PubMed1988

Multiple discrete encephalitogenic epitopes of the autoantigen myelin basic protein include a determinant for I-E class II-restricted T cells.

Immunization with the autoantigen myelin basic protein (MBP) causes experimental allergic encephalomyelitis (EAE). Initial investigations indicated that encephalitogenic murine determinants of MBP were located only within MBP 1-37 and MBP 89-169. Encephalitogenic T cell epitopes within these fragments have been identified. Each epitope is recognized by T cells in association with separate allelic I-A molecules. A hybrid I-E-restricted T cell clone that recognizes intact mouse (self) MBP has been examined. The epitope recognized by this clone includes MBP residues 35-47. When tested in vivo, p35-47 causes EAE. T cell recognition of p35-47 occurs only in association with I-E molecules. These results provide the first clear example that antigen-specific T cells restricted by I-E class II molecules participate in murine autoimmune disease. Furthermore, it is clear that there are multiple (at least three) discrete encephalitogenic T cell epitopes of this autoantigen, each recognized in association with separate allelic class II molecules. These results may be relevant to human autoimmune diseases whose susceptibility is associated with more than one HLA-D molecule.

Amino Acid Sequence↗
PubMed1988

Limited heterogeneity of T cell receptors from lymphocytes mediating autoimmune encephalomyelitis allows specific immune intervention.

Experimental allergic encephalomyelitis (EAE) is an induced autoimmune disease mediated by CD4+ T lymphocytes. Analysis of T cell receptors of myelin basic protein-specific encephalitogenic T cell clones derived from six different PL/J (H-2u) or (PL/J x SJL) F1 (H-2uxs) mice revealed a limited heterogeneity in primary structure. In vivo, the majority of T lymphocytes recognize the N-terminal MBP-nonapeptide in association with I-Au and utilize the V beta 8 gene element. cDNA-sequencing showed that all T cell receptors from a panel of such T cell clones, grown in vitro, share the same V alpha gene segment. Despite heterogeneity in the D-J regions, the clones unexpectedly display a striking similarity in fine specificity. Based on these results, prevention and reversal of autoimmune disease with V beta 8-specific monoclonal antibodies was achieved.

Amino Acid Sequence↗
PubMed1988

A molecular basis for MHC class II--associated autoimmunity.

Class II major histocompatibility (MHC) molecules have an immunoregulatory role. These cell-surface glycoproteins present fragments of protein antigens (or peptides) to thymus-derived lymphocytes (T cells). Nucleotide sequence polymorphism in the genes that encode the class II MHC products determines the specificity of the immune response and is correlated with the development of autoimmune diseases. This study identifies certain class II polymorphic amino acid residues that are strongly associated with susceptibility to insulin-dependent diabetes mellitus, rheumatoid arthritis, and pemphigus vulgaris. These findings implicate particular class II MHC isotypes in susceptibility to each disease and suggest new prophylactic and therapeutic strategies.

Amino Acid Sequence↗
PubMed1988

Predominant expression of a T cell receptor V beta gene subfamily in autoimmune encephalomyelitis.

TCR beta chain gene expression of individual T cell clones that share the same MHC class II restriction and similar fine specificity for the encephalitogenic NH2 terminus of the autoantigen myelin basic protein (MBP) has been examined. TCR V beta expression was examined by FACS analysis with mAbs specific for the V beta 8 subfamily of TCR beta chain genes. 14 of 18 (78%) NH2-terminal MBP-specific clones examined express a member of the TCR V beta 8 subfamily. Southern analysis was used to identify which member(s) of the TCR V beta 8 subfamily is expressed by these clones. Each of four clones examined uses V beta 8.2, though two different V beta 8.2-J beta 2 combinations were identified. Our findings indicate that there is restricted TCR V beta usage in the autoimmune T cell response to the dominant encephalitogenic NH2-terminal epitope of the MBP. The use of an mAb to the antigen-specific TCR in the prevention of T cell-mediated autoimmune disease has been investigated. Our results demonstrate that in vivo administration of a TCR V beta 8-specific mAb prevents induction of autoimmune encephalomyelitis.

Animals↗
PubMed1988

ADP-ribosyltransferase activity of pertussis toxin and immunomodulation by Bordetella pertussis.

Pertussis toxin is produced by the causative agent of whooping cough, Bordetella pertussis, and is an adenosine diphosphate (ADP)-ribosyltransferase capable of covalently modifying and thereby inactivating many eukaryotic G proteins involved in cellular metabolism. The toxin is a principal determinant of virulence in whooping cough and is a primary candidate for an acellular pertussis vaccine, yet it is unclear whether the ADP-ribosyltransferase activity is required for both pathogenic and immunoprotective activities. A B. pertussis strain that produced an assembled pertussis holotoxin with only 1 percent of the ADP-ribosyltransferase activity of the native toxin was constructed and was found to be deficient in pathogenic activities associated with B. pertussis including induction of leukocytosis, potentiation of anaphylaxis, and stimulation of histamine sensitivity. Moreover, this mutant strain failed to function as an adjuvant and was less effective in protecting mice from intracerebral challenge infection. These data suggest that the ADP-ribosyltransferase activity is necessary for both pathogenicity and optimum immunoprotection. These findings bear directly on the design of a nontoxic pertussis vaccine.

ADP Ribose Transferases↗
PubMed1988

A newly characterized HLA DQ beta allele associated with pemphigus vulgaris.

The inheritance of particular alleles of major histocompatibility complex class II genes increases the risk for various human autoimmune diseases; however, only a small percentage of individuals having an allele associated with susceptibility develop disease. The identification of allelic variants more precisely correlated with disease susceptibility would greatly facilitate clinical screening and diagnosis. Oligonucleotide-primed gene amplification in vitro was used to determine the nucleotide sequence of a class II variant found almost exclusively in patients with the autoimmune skin disease pemphigus vulgaris. In addition to clinical implications, the disease-restricted distribution of this variant should provide insight into the molecular mechanisms underlying associations between diseases and HLA-class II genes.

Alleles↗