EXPRESSION OF MHC CLASS-II, CD4-TERM ADRENALECTOMY( AND ED1 MOLECULESIN ASSOCIATION WITH SELECTIVE HIPPOCAMPAL NEURONAL DEGENERATION AFTERLONG)

THE neuroendocrine and the immune systems are interconnected. Monoclon al antibodies against major histocompatibility complex (MHC) class I, class II, CD4, CD8, pan T cells, and macrophages were used for immunos taining brains from adrenalectomized (ADX) and sham-operated rats to i nvestigate the potential involvement of the immune/inflammatory mechan isms in the neurodegeneration of hippocampus after ADX. Our results de monstrate upregulation of MHC class II, CD4 antigens and activated mic roglial marker-ED1 expression selectively in the hippocampus after ADX . The absence of CD5 reactivity precludes that these activated cells w ere T lymphocytes. The activated microglial cells may either be instru mental in the hippocampal neuronal loss or activated secondarily to th e neuronal degeneration after long-term adrenalectomy.