[Immunobiology of the normal and tumor astrocyte]

Immunobiology of the normal and tumoral astrocytes studies interactions between these cells and the immune system. Their antigenic characterization defines 3 classes of antigens: glial antigens, tumor associated antigens (neuroectodermal and gliomatous) and lymphoid differentiation antigens which can be modulated by gamma interferon and other cytokines. Glioma associated antibodies could be used for radiolocalization of tumours and for immunotherapy. The enhancement or induction of the Major Histocompatibility Complex antigen expression by interferon gamma could enhance tumour-antigen presentation by glioma cells to helper and cytotoxic T cells and thus activate the host's immune response. The presence of oncogenes and their products in glioma cells, mainly growth factor receptors, brings new potential therapies using oncogenes products as tumoral markers or as targets for monoclonal antibodies blocking their mitogenic activity. Normal and tumoral astrocytes produce lymphokines: interleukin 1, interleukin 3, prostaglandin E as well as a suppressor factor inhibiting interleukin 2 mediated effects and probably responsible for the suppression of glioma infiltrating T cells. The interaction of astrocytes with several humoral factors related to the immune system and their capacity to function as antigen presenting cells underline their importance for immune reactions within the central nervous system.