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Biomedical subjects

L Steinman

Publications and source records attributed to L Steinman.

At least 181 records · Page 10Linked to original sources
PubMed1990

Mechanisms of anti-CD4-mediated depletion and immunotherapy. A study using a set of chimeric anti-CD4 antibodies.

A family of rat-mouse chimeric anti-murine CD4 antibodies was used to study the mechanisms of anti-CD4-mediated depletion and immunotherapy. The chimeric antibodies retain identical affinity and specificity as the therapeutically effective prototype antibody, rat GK1.5, but are of different mouse isotypes. GK1.5 gamma 1, GK1.5 gamma 2a, and GK1.5 gamma 2b are significantly more effective at CD4+ cell depletion than rat GK1.5 when low doses of antibody are administered. In contrast, no depletion is seen with GK1.5 gamma 3 at any dose. Depletion of CD4+ cells in vivo is not correlated with either the ability of the antibody to mediate C-dependent cytotoxicity or antibody-dependent cell-mediated cytotoxicity in vitro, implying that additional antibody-mediated cytotoxic mechanisms occur in vivo. The chimeric antibodies were used to investigate the mechanism of GK1.5-mediated immunotherapy in a prototypic model of T cell-mediated autoimmunity, experimental allergic encephalomyelitis. Mice treated with a single dose of 100 micrograms of either GK1.5, GK1.5 gamma 1, or GK1.5 gamma 2a showed significant recovery within 72 h. In contrast, mice treated with 100 micrograms of GK1.5 gamma 3 showed only marginal improvement within the first 72 h and regressed within 5 days of treatment initiation. These data suggest that anti-CD4-mediated immunotherapy of murine experimental allergic encephalomyelitis is correlated with depletion of CD4+ cells.

Animals↗
PubMed1990

Limited heterogeneity of rearranged T-cell receptor V alpha transcripts in brains of multiple sclerosis patients.

The identification of activated T cells in the brain of individuals with multiple sclerosis (MS) indicates that these cells are critical in the pathogenesis of this disease. In an attempt to elucidate the nature of the lymphocytic infiltration, we used the polymerase chain reaction to amplify T-cell antigen receptor (TCR) V alpha sequences from transcripts derived from MS brain lesions. In each of three MS brains, only two to four rearranged TCR V alpha transcripts were detected. No V alpha transcripts could be found in control brains. Sequence analysis of transcripts encoded by the V alpha 12.1 region showed rearrangements to a limited number of J alpha region segments. These results imply that TCR V alpha gene expression in MS brain lesions is restricted.

Base Sequence↗
PubMed1990

HTLV-I sequences are not detected in peripheral blood genomic DNA or in brain cDNA of multiple sclerosis patients.

Human T-cell lymphotropic virus (HTLV-I) was recently reported to be etiologically associated with multiple sclerosis (MS). Genomic DNA from peripheral blood lymphocytes and brain plaques of patients with MS was analyzed for the presence of sequences homologous to the HTLV-I pol gene using the polymerase chain reaction and dot blot techniques. Comparison of DNA amplification patterns between patients with MS, and with control subjects who have other autoimmune conditions, with those in healthy control subjects and with an HTLV-I-infected cell line indicates that HTLV-I pol sequence is not present in the peripheral blood of patients with MS, and that the virus is not active in MS brain plaques.

Autoimmune Diseases↗
PubMed1990

Isolation of a complementary DNA clone encoding an autoantigen recognized by an anti-neuronal cell antibody from a patient with paraneoplastic cerebellar degeneration.

We isolated a complementary DNA clone encoding a 52-kd protein recognized by an anti-neuronal cell antibody in serum from a patient with paraneoplastic cerebellar degeneration associated with uterine carcinoma. The recombinant protein expressed in prokaryotic cells was specifically recognized by the anti-neuronal cell antibody from the patient, and its molecular weight was identical to that of antigenic proteins in the cerebellum. The deduced protein consisted of 450 amino acids dominated by hydrophilic residues, the calculated relative molecular mass was 51,238, and the predicted value of the isoelectric point was 4.99. This complementary DNA sequence and the deduced protein sequence have not been reported previously, and the sequences showed no homologies with the complimentary DNA or the amino acid sequences in the GenBank, EMBL, or NBRF databases, including the complementary DNA for a 34-kd cerebellar protein (CDR34) that is recognized by an anti-Purkinje cell antibody. Unexpectedly, the transcript of this gene was detected not only in the cerebellum and the brain stem but also in an extraneural tissue, the intestine.

Amino Acid Sequence↗
PubMed1990

The use of monoclonal antibodies for treatment of autoimmune disease.

Over the past decade monoclonal antibodies have been successfully employed in a number of animal models of autoimmune disease. We have used antibodies to the class II gene products of the major histocompatibility complex, the CD4 molecule on helper T cells, and the T-cell receptor. Monoclonal anti-class II antibodies have been administered to treat paralytic disease in the animal model of multiple sclerosis--experimental allergic encephalomyelitis. These antibodies not only reverse acute paralytic disease but also decrease the number of relapses in a model of relapsing/remitting multiple sclerosis when given after the first attack. The advantage of this form of therapy is that it is haplotype specific. In other words, in a heterozygous individual it is possible to block the major histocompatibility gene associated with disease susceptibility while leaving other major histocompatibility gene products free for antigen presentation. Thus, animals given this form of immunotherapy are not significantly immunosuppressed. Antibodies to the CD4 molecule have been equally effective in treating animal models of autoimmunity. We and others have reversed ongoing paralysis in experimental autoimmune encephalomyelitis. Relapses have been diminished after the administration of anti-CD4. Antibodies to CD4 have been used successfully to treat animal models of systemic lupus erythematosus, rheumatoid arthritis and myasthenia gravis. Recent trials with anti-CD4 have been successful in the treatment of rheumatoid arthritis and cutaneous T-cell lymphoma. The latter trial employed a chimeric human/mouse antibody. Antibodies to the variable region of the T-cell receptor have been employed to treat experimental autoimmune encephalomyelitis.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

HLA-DP beta and susceptibility to multiple sclerosis: an analysis of caucasoid and Japanese patient populations.

Nonradioactive sequence-specific oligonucleotide (SSO) probes specific for the HLA-DP beta locus have been used in a simple dot-blot assay to DP beta-type samples amplified by the polymerase chain reaction (pcr) from Caucasoid (n = 24) and Japanese (n = 23) patients with multiple sclerosis (ms) as well as ethnically matched controls. In contrast to previous reports, no DP beta allele was found to be increased in either patient population. However, the results do show a dramatic difference in the allele frequencies between the two control populations, further emphasizing the need for ethnically matched controls in studies of HLA and disease.

Alleles↗
PubMed1990

Increased incidence of certain TCR and HLA genes associated with myasthenia gravis in Italians.

In order to study the immunogenetics of myasthenia gravis (MG), we analysed the TCR and HLA-class II genes from Italian and Californian myasthenic patients. We investigated polymorphisms of the TCR using the full length cDNA probes pGA5 and the pT10 for the alpha and beta chains, respectively. The 6.3 kb and 2.0 kb polymorphic markers, revealed by the PssI enzyme and the alpha chain probe, were shown to be significantly associated with MG. Italian MG patients were HLA typed, and allele frequencies showed a significant association of DR3 and DQw2 with MG. The relative risk calculated for DR3 was 7.4. T-cell proliferative responses to peptides of the AchR alpha chain were also studied and no associations with TCR RFLP analysis or HLA-class II typing were observed.

Amino Acid Sequence↗
PubMed1990

Lymphotoxin and tumor necrosis factor-alpha production by myelin basic protein-specific T cell clones correlates with encephalitogenicity.

Lymphokine activity in seven myelin basic protein (MBP)-specific T cell clones was examined. All of the clones recognize MBP peptide 1-9 in the context of I-Au. A strong positive correlation was found between levels of lymphotoxin (LT) and tumor necrosis factor alpha (TNF-alpha) mRNA and biological activity on L929 cells and their capacity to induce paralysis, the clinical hallmark of experimental allergic encephalomyelitis (EAE). No correlation was found between interleukin-2 or gamma interferon production and encephalitogenicity. LT and/or TNF-alpha may play a central role in the pathogenesis of EAE.

Animals↗
PubMed1990

Inhibition of T cell proliferation specific for acetylcholine receptor epitopes related to myasthenia gravis with antibody to T cell receptor or with competitive synthetic polymers.

Long-term T cell lines and clones of C3H.SW origin specific to synthetic peptides representing immunogenic epitopes of the human aetylcholine receptor alpha-subunit were established. Using these lines and clones, it was possible to characterize the T cell recognition process of myasthenic epitopes. Testing a panel of N-and/or C-terminal truncated peptides it could be demonstrated that the deletion of the two C-terminal amino acids of peptides p195-212 and p259-271 resulted in a loss or reduction of the stimulatory capacity of the peptides towards the specific T cell lines. In contrast, no substantial effect on the stimulation of the line could be observed by shortening peptide p195-212 by up to five amino acids at the N-terminal end. The proliferation of T cell lines and clones specific to peptide p195-212 was inhibited by a mAb directed against the V beta 8 region of the T cell receptor. Furthermore, it was possible to block the peptide-specific proliferative responses of the lines and clones by the I-Ab restricted synthetic polypeptide (T, G)-A--L but not by the I-Ak restricted polypeptide antigen (H,G)-A--L. Similarly, p195-212 inhibited the proliferative response of the TCSW259-271 T cell line and p259-271 inhibited the specific proliferative response of the TCSW195-212 line. Moreover, the C-terminal shortened peptides inhibited significantly the in vitro stimulation of the T cell lines by the immunogenic peptides p195-212 and p259-271. The inhibition by the synthetic peptides or by (T,G)-A--L may be due to competitive blockade of the MHC binding site for the T cell line stimulating AChR peptides.

Amino Acid Sequence↗
PubMed1990

Prospects for specific immunotherapy in myasthenia gravis.

Myasthenia gravis is an autoimmune disease resulting from a breakdown in T and B cell tolerance to acetylcholine receptor (AChR). Autoantibodies to AChR mediate the disease. Recent advances in experimental immunotherapy of autoimmune disease provide several possibilities for specific intervention in this well-characterized condition.

Humans↗
PubMed1990

T cell recognition in experimental autoimmune encephalomyelitis: prospects for immune intervention with synthetic peptides.

Peptide binding and lymph node T cell activation studies have been used to characterize T cell recognition of an encephalitogenic T cell autoantigen from myelin basic protein in mice of the H-2u haplotype. An important role for MHC class II molecules in "determinant selection" is revealed. Amino acids which determine interactions with either the restriction element of the major histocompatibility complex (MHC) or the encephalitogenic T cell receptor are defined. This information enables the design of peptides which bind MHC yet do not crossreact with the autoantigen. Two such peptides compete with the autoantigen for binding to the disease associated class II molecule and inhibit induction of experimental autoimmune encephalomyelitis in H-2u mice. Prospects for peptide mediated therapy are discussed.

Amino Acid Sequence↗
PubMed1990

Inhibition of autoimmune uveitis by anti-CD4 antibody.

In this study, rats with S-antigen-induced uveitis were treated with W3/25, a monoclonal antibody that recognizes the CD4 molecule expressed by helper/inducer cells. Treatment was started on day 5 after administration of S-antigen. Groups of animals were killed 18 or 31 days after S-antigen injection. The enucleated globes were studied histologically, and in vitro T-cell response and anti-S antibody levels were determined. Results showed that the antibody treatment prevented development of experimental autoimmune uveitis (EAU) in all animals. Furthermore, there was no evidence of disease development for 14 days after cessation of therapy. These results suggest that CD4+ cells are important in the initiation of EAU, and that monoclonal antibodies directed to this subset may provide effective treatment of autoimmune uveal inflammation.

Animals↗
PubMed1990

Development of antigen-specific therapies for autoimmune disease.

Reversal of autoimmune disease with monoclonal antibodies to polymorphic determinants associated with class II gene products of the major histocompatibility complex (MHC) and to T-cell receptor variable region segments has been demonstrated in animal models. Recent studies have shown that it is also possible to use mutant peptides to block recognition of self-antigen associated with MHC by T-cells that mediate autoimmune disease. These mutant peptides have been used to prevent the model autoimmune condition experimental allergic encephalomyelitis. The possibility of extending these approaches to human disease is discussed.

Amino Acid Sequence↗
PubMed1989

Multiple T and B cell epitopes in the S1 subunit ("A"-monomer) of the pertussis toxin molecule.

The immunogenicity and reactogenicity of Bordetella pertussis vaccine are mediated in part by the S1 subunit of pertussis toxin (PT). To identify the immune epitopes in the S1 subunit of PT, synthetic peptides were prepared and tested for their capacity to induce antibodies in mice with different MHC genotypes. In BALB/c mice, peptides corresponding to sequences 1-17, 70-82 and 189-199 generate T cell proliferative responses, induce the production of antibodies capable of neutralization of the toxin in the Chinese hamster ovary-cell assay, and protect mice from a shock-like syndrome caused by alternate injections of BSA and PT. Protection and neutralization correlated with the ability of these peptides to elicit high anti-PT titers. Different B cell epitopes were detected in other inbred mouse strains. The antibody reactivity against synthetic peptides from two infants vaccinated with pertussis vaccine was tested. These infants had antibodies reactive to a variety of epitopes in the S1 subunit, including peptides 1-17, 70-82, 99-112, 135-145, and 189-199. Thus, it appears that there are multiple T and B cell epitopes in the S1 subunit of PT.

Algorithms↗
PubMed1989

Antigen recognition in autoimmune encephalomyelitis and the potential for peptide-mediated immunotherapy.

Peptide binding and lymph node T cell activation studies have been used to characterize T cell recognition of an encephalitogenic T cell autoantigen from myelin basic protein in (PL/J x SJL)F1 mice. Amino acids that determine interactions with either the restriction element of the major histocompatibility complex (MHC) or the encephalitogenic T cell receptor are defined. This information enables the design of peptides that bind MHC yet do not cross-react with the autoantigen. A peptide analog of the encephalitogenic epitope is shown to be "heteroclitic" for MHC binding and activation of encephalitogenic T cells in vitro. This analog is not immunogenic for encephalitogenic T cells in vivo and is shown to inhibit disease that is induced by the autoantigen itself.

Amino Acid Sequence↗