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Biomedical subjects

C Goridis

Publications and source records attributed to C Goridis.

At least 109 records · Page 6Linked to original sources
PubMed1982

Inhibition of murine T cell-mediated cytolysis and T cell proliferation by a rat monoclonal antibody immunoprecipitating two lymphoid cell surface polypeptides of 94 000 and 180 000 molecular weight.

The monoclonal antibody methodology was use to identify membrane structures involved in T cell functions. To optimize chances to produce and detect relevant antibodies, a xenogeneic sensitization protocol was utilized and hybridoma supernatants were screened, on functional rather than structural grounds, for their ability to inhibit a given function. The test function was T cell-mediated cytolysis. Mouse cytolytic anti-allogeneic cell populations were used to sensitize a rat, the spleen cells of which were fused to produce hybridomas; the supernatants of the latter were screened for their ability to inhibit mouse T cell-mediated cytolysis in vitro. Several inhibitory antibodies were obtained, one of which, H35-89.9 monoclonal antibody, was studied in more detail. It inhibited specific and concanavalin A (Con A)-mediated cytolysis by T cells, by acting on the effector cells. It reversibly inhibited soluble antigen-, alloantigen and Con A-induced T cell proliferation (but not LPS-induced B cell proliferation), after the production of interleukin 2, by acting on the responder cells. It also had a desagglutinating effect on Con A and LPS blasts and on EL4 cells. In immunoprecipitated from thymocyte membrane preparations two structures of 94 000 and 180 000 apparent molecular weight, and recognized cell surface determinants on both T and B lymphocytes. Our findings suggest that several antibodies directed against distinct effector cell membrane structures inhibit cytolysis. The case of H35-89.9 monoclonal antibody, which exerts multiple functional effects and immunoprecipitates two membrane polypeptides, raises the problem of the various possible relationships between these structures and functions.

Animals↗
PubMed1982

Tissue- and developmental stage-specific forms of a neural cell surface antigen linked to differences in glycosylation of a common polypeptide.

We have previously identified a cell surface glycoprotein of the mouse nervous system named brain cell surface protein-2 (BSP-2). Here we report that this antigen is not a single, discrete entity, but a family of antigenically and structurally related molecules. Three components of 180, 140, and 120 K were characteristic for more mature nervous tissues. Adult cerebral cortex contained the 140-K and 120-K antigens, adult spinal cord only the 120-K, and dorsal root ganglia from young mice mainly the 180-K component. Very different forms of the antigen that migrated as a diffuse zone from 180-250-K in SDS-polyacrylamide gels were found in immature nervous tissues. A molecule different from the previous ones was found in a neuroblastoma line. Evidence is presented that the structural diversity of BSP-2 is due to differences in glycosylation. This result indicates that cell type- and developmental stage-specific glycoprotein patterns previously found in the nervous system may in part be due to different glycosylation of identical polypeptides. The finding that a neural cell surface protein may be glycosylated in different ways has important implications for the generation of cell surface specificity.

Aging↗
PubMed1982

Monoclonal antibodies as neural cell surface markers.

A comparison is made of the immunohistochemistry at the ultrastructural level of three monoclonal antibodies directed against surface components of DNS cells. Hybridomas secreting these antibodies were obtained from two cell fusions of a rat myeloma cell line and immune splenocytes derived from rats immunized either with primary mouse brain cultured cells or membrane components. In cultures one antibody, anti-BSP2 (Brain Surface Protein-2), was preferentially directed against neurons while another, anti-BSP-3 (Brain Surface Protein-3), preferentially labeled astrocytes. In mouse cerebellar sections, both labeled the surface of Purkinje cells, granule cells and astrocytes. In addition a cytoplasm localization was apparent in granule cells and astrocytes. Another antibody anti-MESA-1 (Mouse Endothelial Surface Antigen-1) reacted exclusively with the surface of endothelial cells lining blood vessels. These data are discussed with reference to the biochemical nature of the corresponding antigens and to known glycoproteins of neural cell membranes.

Animals↗
PubMed1982

A new brain cell surface glycoprotein identified by monoclonal antibody.

Of 207 monoclonal antibodies produced against cultured mouse cerebellar cells, 16 reacted with cerebellar cell surfaces and 4 reacted with glycoproteins. One of them, called an anti-BSP-3 (Brain cell Surface Protein-3) defines a 48,000 molecular weight protein which can be iodinated at the surface of cultured cerebellar cells. Lectin-binding and sugar incorporation studies established the glycoprotein nature of the antigen. Astroglia (glial fibrillary acidic protein-positive cells) in primary cerebellar cultures were labelled intensely for this antigen by the indirect immunofluorescence method while neuronal cells and their processes were more weakly labelled. Fibronectin-positive cells were negative for BSP-3. In cerebellar sections using the immunoperoxidase method at both the optical and electron microscope levels, the difference in staining intensity between astrocytes and neuronal cells was not significant: in Purkinje cells and in the large neurones present in the deep cerebellar nuclei the immunoperoxidase percipitate was confined to the plasma, membrane while in both astrocytes and granule cells cytoplasmic labelling was also observed. Oligodendrocytes do not appear to react with the anti-BSP-3 monoclonal antibody; neither do endothelial or leptomeningeal cells. The availability of a monoclonal antibody produced by a stable hybridoma line will be a powerful tool in attempts to purify the BSP-3 antigen and to elucidate its function.

Animals↗
PubMed1982

Lymphoid cell surface interaction structures detected using cytolysis-inhibiting monoclonal antibodies.

We screened monoclonal antibodies obtained by xenogeneic immunization for their capacity to inhibit T cell-mediated cytolysis. These antibodies fell into two classes according to the cell structures they recognized, of 30-35 K and 94-180 K apparent molecular weight, respectively. The main features of these structures and of their interaction with the corresponding antibodies were reviewed. The inhibition of cytolysis by these antibodies was shown to occur mainly at the effector cell level, at the recognition stage of cytolysis, and to depend on the nature of target cells, effector cells, and link between these cells. T cell functions other than cytolysis were also inhibited by some of these antibodies. We considered various possible mechanisms to account for the inhibition of cytolysis by these mAb. We favor an hypothesis based on inhibition by these mAb of lymphoid cell surface interaction structures. This hypothesis was discussed within the general framework of cell interaction structures in immunological and non-immunological experimental systems.

Animals↗
PubMed1982

A surface marker for murine vascular endothelial cells defined by monoclonal antibody.

Spleen cells from a rat immunized with mouse cerebellar cells were fused with mouse myeloma cells. One of the hybridomas secreted a monoclonal antibody that reacts with a surface antigen on vascular endothelial cells. The antibody stained endothelial cells lining blood vessels in brain, heart, lung, kidney, and liver. It did not, however, stain endothelial cells lining hepatic sinusoids. Parenchymal cells were always negative. So far, an antigen of similar tissue distribution has not been described in the mouse and we have called it mouse endothelial surface antigen-1 (MESA-1). The antibody could be used as a highly specific usefulness for identifying endothelium-derived cells in culture has been demonstrated on cultures of dissociated mouse cerebellum, where it stained a subclass of fibronectin-expressing cells.

Animals↗
PubMed1981

Monoclonal antibody against cell surface glycoprotein of neurons.

A monoclonal antibody, named BSP-2, has been produced against glycoproteins extracted from neonatal mouse brain. Its reactivity with live cells established the surface location of the antigen. In primary cultures of dissociated cerebellar cells, the antibody bound to neuronal cell types, but not to astrocytes nor to fibroblasts. Immunoprecipitates prepared with the BSP-2 antibody contained a triplet of high-molecular weight glycoproteins with apparent molecular weights of 180,000, 140,000 and 120,000.

Animals↗
PubMed1981

Biosynthetic incorporation of [75Se]selenomethionine: a new method for labelling lymphocyte membrane antigens.

A novel approach for radiolabelling lymphocyte membrane antigens is described. This technique is based on the use of the gamma-emitting amino acid analogue [75Se]selenomethionine. Human HLA-A, B, C and DR heavy and light chains and mouse Ia antigens were efficiently labelled by this technique and were precipitated with monoclonal antibodies. Approximately the same radioactivity was incorporated into the HLA-A, B, C chains whether [75Se]selenomethionine, [35S]methionine or [3H]leucine were used as precursors. Easily detectable as a gamma-emitter, [75Se]selenomethionine thus constitutes a useful biosynthetic label of lymphocyte surface antigens. The same method was used to label immunoglobulins produced by hybridomas and to determine the nature of the secreted light chains.

Animals↗
PubMed1981

A solid-phase radioimmunoassay for detecting antibodies to brain cell surface antigens.

A trace radioimmuno-binding assay is described which utilizes microcultures of dissociated cerebellar cells from neonatal mice as targets for the binding of antibodies to surface antigens on normal brain cells. This microassay is easy to perform, highly sensitive and economical in terms of cells and antibodies. Results are presented showing its specificity for antigens accessible at the cell surface. For the assay, dissociated cells are cultured in polylysine-coated wells of 60-well Terasaki microtest plates. After a recovery period allowing extensive outgrowth of neurites, the cultures are incubated with antibody solution, and bound antibody is revealed by an iodinated second antibody. This monolayer binding assay is particularly suited to the screening of large numbers of samples, for instance when trying to raise monoclonal antibodies against brain cells by the hybridoma methodology. The test can also be used for the analysis of anti-surface specificities in conventional antisera.

Animals↗
PubMed1981

Clones of human cytotoxic T lymphocytes derived from an allosensitized individual: HLA specificity and cell surface markers.

By planned immunization of a volunteer, two stable (greater than or equal to 6 months), specific, alloreactive cytolytic T-cell clones have been established from his peripheral blood lymphocytes. One clone reacts with all serologically defined HLA-Cw3 cells from our panel, whereas the other defines a split within the serological HLA-B40 specificity. The two cytotoxic clones are SmIg-negative, E-rosette positive, EA and EAC rosette-negative, HLA-A, -B and -C- positive, and also HLA-DR- or 'Ia like'-positive. In addition, they present very similar patterns of iodinated cell surface molecules as analysed by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE), contrasting with that of an EBV cell line derived from the same donor.

Adult↗
PubMed1980

Identification and characterisation of two surface glycoproteins on cultured cerebellar cells.

Two high molecular weight surface glycoproteins of cerebellar cells which are selectively labeled by lactoperoxidase-catalyzed iodination of monolayer cultures from the developing mouse cerebellum, have been identified and partially characterised. Both molecules, called peak 2 and peak 3 proteins, were the major glycoprotein species detected in cerebellar cell cultures after labelling with various radioactive sugars. The freshly iodinated molecules were firmly bound to the cells, but they were released into the medium upon prolonged incubation on the cultures. The soluble peak 2 and peak 3 proteins recovered from the medium comigrated on SDS-polyacrylamide gels with their cell-bound counterparts. Thus, their release results from mechanisms other than extensive degradation. The soluble proteins eluted from gel columns corresponding to molecular weights of over 500,000 and around 300,000, for peaks 2 and 3, respectively. They bound to and were specifically eluted from concanavalin A-Sepharose columns. Peak 3 protein could be easily identified as the most prominent iodinatable polypeptide in cerebellar cell cultures. Its surface expression depended on the presence of neuronal cells. After degeneration of neuron-like cells, a component of greater molecular weight than peak 3 or 2 was predominantly labeled by surface iodination. Peak 2 protein was quantitatively precipitated from labeled culture medium by two heterologous antiseRA. Anti-peak 2 activity was removed from the antiserum by absorption with adult mouse brain, but not by liver, spleen, thymus, kidney, heart and lung. Thus, peak 2 protein may be considered as a brain-specific glycoprotein.

Animals↗
PubMed1977

Guanylate cyclase activity and cyclic nucleotide concentrations during liver regeneration after experimental injury.

Cyclic nucleotide concentrations and guanylate cyclase activity were measured in regenerating rat liver. Previous work has shown that in livers of partially hepatectomized rats the activity of a membrane-bound guanylate cyclase increases considerably during the early replicative phase [Kimura & Murad (1975) Proc. Natl. Acad. Sci. U.S.A.72, 1965-1969; Goridis & Reutter (1975) Nature (London) 257, 698-700]. Over the same time period after partial hepatectomy, increased tissue concentrations of cyclic GMP were found when the rats were killed under pentobarbital anaesthesia, but not when anaesthesia was omitted. The results obtained on hepatectomized livers were compared with the changes in guanylate cyclase activity and cyclic nucleotide concentrations during the response to galactosamine treatment. Here, a peak of guanylate cyclase activity and of cyclic GMP concentrations occurred at 8h, that is before the beginning of the proliferative response. Both parameters were normal at the time of increased DNA synthesis. There does not, therefore, seem to be a consistent correlation between changes in guanylate cyclase activity or concentrations of cyclic GMP and an increase in liver DNA synthesis. A modest rise in cyclic AMP concentrations was found, however, in livers of galactosamine-treated rats, which was coincident with the time of DNA synthesis.

Animals↗