DIFFERENTIATION OF AN IMMORTALIZED CNS NEURONAL CELL-LINE DECREASES THEIR SUSCEPTIBILITY TO CYTOTOXIC T-CELL LYSIS IN-VITRO

RN33B cells are a temperature-sensitive neuronal cell line derived fro m rat E12 medullary raphe nucleus (Whittemore and White (1993) Brain R esearch 615, 27-40). Undifferentiated RN33B cells express class I but not class II antigens of the major histocompatibility complex (MHC), a nd intercellular adhesion molecule-1 (ICAM-1), a ligand for lymphocyte function associated antigen-1 (LFA-1), expressed on cytotoxic T lymph ocytes (CTLs). Treatment of undifferentiated RN33B cells with interfer on-gamma (IFN-gamma) upregulated both class I MHC and ICAM-1. After ne uronal differentiation, expression of class I MHC antigens or ICAM-1 w as undetected, even after IFN-gamma treatment. The neuronally differen tiated RN33B cells were also markedly less susceptible to lysis by all oantigen-specific CTLs. These data suggest that intrinsic to the diffe rentiation of CNS neurons is a mechanism to escape CTL-mediated cell l ysis.