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Biomedical subjects

L Steinman

Publications and source records attributed to L Steinman.

At least 163 records · Page 9Linked to original sources
PubMed1992

Analysis of the T cell repertoire using the PCR and specific oligonucleotide primers.

Applications of PCR have revolutionized the field of immunogenetics particularly in studies of human leukocyte antigen class II polymorphism and more recently in the analysis of T cell receptor usage. The diversity of the variable region of the T cell receptor, however, has made it difficult to amplify the complete repertoire of T cell receptor transcripts. We have chosen to address this problem through the design of oligonucleotide primers specific for each of the known V alpha- and V beta-region T cell receptor families in order to characterize the T cell receptor repertoire. Using nonradioactive probes labeled with horse radish peroxidase, the system presented here allows for the rapid elucidation of the T cell receptor repertoire expressed in cells or tissue samples, such as those derived from autoimmune lesions. The identification of the T cell receptor repertoire involved in a pathogenic process can have therapeutic implications given the success of reversing experimental autoimmune disorders by directing specific forms of immunotherapy against V region gene products.

Actins↗
PubMed1992

[An analysis of lymphokine gene expression within astrocytoma].

Expression of the lymphokine genes in human astroglial cell lineage was studied. Primers for 9 different human lymphokines, from IL-1 alpha to IL-8, were used to analyze RNA transcripts in 5 cultured human astrocytoma, one neuroblastoma cell line and 4 fresh brain specimens by polymerase chain reaction (PCR). mRNA transcripts of neither IL-1 nor IL-3, the biological activities of which were observed in rat primary cultured astrocytes, could be detected within these cell lines. Two out of 5 unstimulated astrocytomas, U138 and U373, expressed IL-6 genes. IL-8 gene was detected within U87, U138, U251, U373 glioma cells. After stimulation with IL-1 beta, all astrocytoma and one neuroblastoma cell line expressed IL-6 and IL-8 genes. In addition to the cultured cells, we examined IL-6 and IL-8 gene expression within human malignant astrocytoma specimens. The result shows that three out of four glioma specimens expressed IL-6 and IL-8 genes. From these results, it is suspected that astroglial cell-derived IL-6 or IL-8 may participate in local immune reactions accompanying infection, degeneration and malignancies in the central nervous system.

Astrocytoma↗
PubMed1991

A single amino acid change in a myelin basic protein peptide confers the capacity to prevent rather than induce experimental autoimmune encephalomyelitis.

Experimental autoimmune encephalomyelitis (EAE) is an experimental demyelinating disease of rodents. In (PL/J x SJL) F1 mice, it is induced by immunization with the myelin basic protein peptide Ac1-11. Ac1-11 [4A], a myelin basic protein peptide analog with a single amino acid substitution, (i) binds to class II major histocompatibility complex molecules and stimulates encephalitogenic T cells in vitro better than Ac1-11, (ii) is nonimmunogenic and nonencephalitogenic in vivo in (PL/J x SJL)F1 mice, (iii) prevents EAE when administered before or at the time of immunization with Ac1-11, and (iv) prevents EAE when administered later, near the time of disease onset. Initial studies suggest that Ac1-11 [4A] does not prevent EAE by competitive inhibition or by activation of regulatory cells. Thus, substitution of a single amino acid in a myelin basic protein peptide confers the capacity to prevent rather than induce EAE, even after peptide-specific encephalitogenic T cells have been activated.

Amino Acid Sequence↗
PubMed1991

An analysis of T-cell-receptor variable-region genes in tumor-infiltrating lymphocytes within malignant tumors.

Expression of T-cell-receptor (TCR) V alpha and V beta genes in tumor-infiltrating lymphocytes (TILs) of 29 patients, 15 melanomas and 14 malignant glial tumors (glioma and medulloblastoma), was investigated. The identification and propagation of T cells with anti-tumor reactivity is crucial to the understanding of the human immune response to tumors, which may possibly be useful in the successful implementation of adoptive immunotherapy against cancer. Despite clinical evidence that a more favorable prognosis is associated with the degree of lymphocyte infiltration within a tumor, the actual role of TIL remains uncertain. In order to address this question, we examined the diversity of the RNA transcripts of TCR genes in TILs within 29 specimens obtained at surgery. Using the polymerase-chain-reaction (PCR) method and primers for 18 different human TCR V alpha and 21 V beta families to analyze TCR V-(D)-J-C gene rearrangements, we detected a limited expression of TCR variable-region V alpha genes of TILs. TCR V beta gene rearrangements were more diverse than those for V alpha. In addition to restricted usage of TCR V alpha genes, preferential expression of V alpha 7 genes was found in 20 out of 29 cases (69%). Predominant usage of V alpha 7 genes was more remarkable in melanoma TILs (14/15) than in glial tumor TILs (6/14). These findings were also confirmed by Southern blot analysis with oligonucleotide probes for the constant (C) region of TCR alpha and beta chains. We suspect that some specific T-cell populations may be directed to antigenic determinants in melanoma cells.

Base Sequence↗
PubMed1991

T-cell receptor V beta gene expression differs in tumor-infiltrating lymphocytes within primary and metastatic melanoma.

Expression of T-cell receptor (TCR) gene rearrangements in tumor-infiltrating lymphocytes (TILs) within primary and metastatic melanoma specimens was studied. In order to analyze TCR gene transcription in TILs within these tissues, we analyzed reverse transcribed complementary DNA from mRNA directly from tissues using the polymerase chain reaction. The polymerase chain reaction-amplified products were confirmed by dot or Southern blot hybridization with C alpha or C beta oligoprobes. First, we investigated the diversity of TCR V alpha and V beta gene usage in human malignant melanoma patients with multiple metastasis. We found in one patient, bearing multiple skin lesions, that the patterns of TCR V alpha and V beta repertoires in different sites of the skin (leg and chest wall) were almost the same. However, in another patient with skin and brain melanomas, different TCR repertoires were presented. Next, we examined the usage of murine TCR V beta genes in TILs within the primary and metastatic sites (liver, lung, and brain) of C57BL/6 mice bearing B16-F10 murine melanoma. The population of TILs in each primary and metastatic site expressed from one to four TCR V beta genes. In each metastatic site, the profile of TCR V beta gene expression was different. A different TCR V beta usage in TILs distributed within metastases of various organs may reflect differences in tumor antigenicity at these sites or may be due to differential homing patterns to these tumors.

Animals↗
PubMed1991

Observations on the effect of chimeric anti-CD4 monoclonal antibody in patients with mycosis fungoides.

Chimeric (murine/human) anti-CD4 monoclonal antibody was infused into seven patients with mycosis fungoides. Successive patients received doses of 10, 20, 40, and 80 mg of antibody twice a week for 3 consecutive weeks. All patients had some clinical improvement, but responses were of relatively short duration. Serum levels of chimeric antibody varied as a function of dose. At the 80-mg dose level, antibody was readily observed in biopsied skin lesions. Although there was coating by antibody of most CD4 positive cells in the blood, there was no significant depletion of CD4 positive cells. Low-level antibody responses against the mouse Ig variable region and human Ig allotypic constant region determinants were observed in several patients, but none were of clinical significance. All but two patients made primary antibody and T-cell proliferative responses to a simultaneously administered foreign protein test antigen. However, there was marked suppression of the mixed lymphocyte reaction. We conclude that at the dose levels studied, a chimeric anti-CD4 monoclonal antibody (1) had some clinical efficacy against mycosis fungoides; (2) was well tolerated; (3) had a low level of immunogenicity; (4) had immediate immunosuppressive effects; and (5) did not induce tolerance to a co-injected antigen.

Adult↗
PubMed1991

Lymphocytes cytotoxic to uveal and skin melanoma cells from peripheral blood of ocular melanoma patients.

To study antitumor immunity in patients with choroidal melanoma, T cells were generated from the peripheral blood of choroidal melanoma patients by mixed lymphocyte/tumor cell culture (MLTC). Because autologous tumors are generally unavailable, an allogeneic choroidal melanoma cell line, OCM-1, was used as the specific stimulus. Lymphocyte cultures from 27 patients were characterized by cell-surface phenotypes, patterns of reactivity towards cells of the melanocytic origin and T-cell-receptor gene usage. Antimelanoma reactivity was found in cell-sorter-purified CD4+ and CD8+ T cell subsets. To analyze this reactivity, sorter-purified CD4+ and CD8+ cells from a MLTC were cloned by limiting dilution in the presence of exogenous interleukin-2 and interleukin-4 as well as irradiated OCM-1. Under these conditions, CD4+ T cells did not proliferate, perhaps because of the absence of antigen-presenting cells. However, CD8+ grew vigorously and 29 cytolytic CD8+ T cell clones were isolated. On the basis of their pattern of lysis of OCM-1, a skin melanoma cell line M-7 and its autologous lymphoblastoid cell line LCL-7, the clones were categorized into three groups. Group 1, representing 52% of the clones, lysed all three target cells, and are alloreactive. However, since OCM-1 and M-7 did not share class I antigens, these clones recognized cross-reactive epitope(s) of the histocompatibility locus antigen (HLA) molecule. Group 2, constituting 28% of the clones, lysed both the ocular and skin melanoma cell lines but not LCL-7, and were apparently melanoma-specific. Unlike classical HLA-restricted cytolytic T lymphocytes, these T cells might mediate the lysis of melanoma cells via other ligands or a more degenerate type of HLA restriction. For the latter, the HLA-A2 and -A28 alleles would have to act interchangeably as the restriction element for shared melanoma-associated antigen(s). Group 3, representing only 10% of the T cell clones, was cytotoxic only to OCM-1, but not to M-7 or LCL-7. These clones may recognize antigens unique to ocular melanoma cells. Our data suggest that choroidal melanoma patients can recognize melanoma-associated antigens common to both ocular and cutaneous melanoma cells, and presumbly their autologous tumor. Thus, choroidal melanoma, like its skin counterpart, may be responsive to immunotherapeutic regimens such as active specific or adoptive cellular immunotherapy.

Antigens, Differentiation, T-Lymphocyte↗
PubMed1991

New approaches to the therapy of demyelinating disease.

The pace of research on the pathogenesis and treatment of multiple sclerosis, the principal human demyelinating disease of the central nervous system, has intensified in the past 3 years, due in part, to the application of advances in molecular and cellular immunology. Many lessons that have been learned in an animal model of central nervous system demyelinating disease, experimental allergic encephalomyelitis, also apply to multiple sclerosis and certain successful approaches for the treatment of this disease are now being attempted in humans.

Animals↗
PubMed1991

Modulation of MHC class II antigen expression in human myoblasts after treatment with IFN-gamma.

Some investigators have proposed myoblast transfer as a potential therapy for the treatment of Duchenne muscular dystrophy. Little is known about the immunobiology of myoblast transplantation. Transplantation rejection is mediated to a large extent by CD8+ T cells, which recognize alloantigens encoded by class I HLA genes, and by CD4+ T cells, which recognize alloantigens encoded by class II HLA genes. Gamma interferon (IFN-gamma) is a potent inducer of HLA class II molecules as well as beta 2-microglobulin, which is co-expressed with HLA class I. IFN-gamma may be a critical cytokine involved in graft rejection. We purified human myoblasts by flow cytometry and incubated them in vitro for varying time periods with recombinant human IFN-gamma. The inducibility of HLA-DR and -DP molecules raises a note of caution concerning possible rejection phenomenon which might occur following myoblast transplantation.

Cells, Cultured↗
PubMed1991

Trimolecular interactions in experimental autoimmune demyelinating disease and prospects for immunotherapy.

Experimental allergic encephalomyelitis (EAE) is a T cell mediated model of demyelinating disease that develops as a result of an autoimmune response to the myelin structural antigen, myelin basic protein (MBP). Much information has accumulated on the nature of trimolecular interactions which lead to the activation of self-reactive T lymphocytes in this disorder. Many parallels exist in the etiopathogenesis of EAE and multiple sclerosis (MS). Based upon these similarities selective immunotherapy that targets either class II molecules of the major histocompatibility complex or T cell receptor variable region genes will be described for EAE with consideration given to application of these principles in MS.

Amino Acid Sequence↗
PubMed1991

[Expression of cytokine genes within astrocytoma cell lines and brain specimens].

Expression of the Cytokine genes in human astroglial cell lineage was studied. Primers for 5 different human cytokine, TNF-alpha, -beta, IFN-gamma, G-CSF and GM-CSF, were used to analyze messenger RNA transcripts in 5 cultured human astrocytoma, one neuroblastoma cell lines and fresh brain specimens by polymerase chain reaction (PCR). Three out of 5 unstimulated astrocytomas, U138, U251, U373 MG and IMR32 neuroblastoma cells expressed TNF-alpha genes. After stimulation with IL-1 beta (1000 U/ml) all these cell lines expressed TNF-alpha genes. TNF-beta genes could not be detected in these cell lines even in the presence of any cytokine stimuli. We were able to detect expression of IFN-gamma genes within 2 astrocytoma cell lines (U87MG and A172), which interestingly did not show TNF-alpha activity. Constitutive expression of mRNA transcripts of GM -CSF could be detected in all astrocytoma and two out of 5 unstimulated astrocytomas, U87MG and U138MG, expressed G-CSF genes. After stimulation with IL-1 beta, all cell lines expressed G-CSF. In addition, we also examined gene expression of these cytokines within 4 human malignant astrocytoma specimens, 2 peritumoral brain and 2 autopsied normal brains. The results show that tumor and surrounding lesions express TNF-alpha (4 of 6), TNF-beta (1/6), IFN-gamma (4/6), G-CSF (3/6) and GM-CSF (5/6) but not normal brains. One tumor specimen also expresses TNF-beta as well as TNF-alpha genes (case 2). From these results, it is suspected that astroglial cell-derived cytokines may participate in local immune reactions accompanying glioma in the brain.

Astrocytoma↗
PubMed1990

Predominant expression of T cell receptor V alpha 7 in tumor-infiltrating lymphocytes of uveal melanoma.

Expression of T cell receptor (TCR) V alpha genes in tumor-infiltrating lymphocytes (TILs) within intraocular melanoma was studied. Primers for 18 different human TCR V alpha families were used to analyze TCR V alpha-C alpha gene rearrangements in TIL in these melanomas obtained at surgery. A limited number of TCR V alpha genes were expressed and rearranged in these tumors, and TILs expressing V alpha 7 were found in seven of eight of these uveal melanomas. TCR gene usage is also restricted in experimental autoimmune disease, in T cells within organs like skin and other epithelial tissues, and in the brain of patients with multiple sclerosis (MS). The restricted usage of TCR genes in TIL may indicate that a specific antigen in these melanomas is targeted.

Base Sequence↗