Cytotoxic effect of myelin basic protein-reactive T cells on cultured oligodendrocytes.

To help clarify effector mechanisms in experimental allergic encephalitis (EAE), the cytotoxic effects of myelin basic protein (MBP)-reactive lymphocytes on oligodendrocytes were studied using a 51Cr release assay. MBP-reactive encephalitogenic T cell lines were cytotoxic to 51Cr-labeled oligodendrocyte target cells derived from Lewis rat fetal brain-dissociated culture, when incubated for 6 h in the presence of antigen-presenting cells (APC) and MBP (percent 51Cr release = 65 +/- 3% vs. spontaneous release = 22 +/- 3% vs. normal lymph node cells + APC and MBP = 20 +/- 3%). This reaction is time dependent, likely MHC restricted, and is not just a nonspecific toxic effect against any Lewis target cells since neither fibroblasts nor astrocytes were affected. Other (tetanus toxoid-reactive) lymphoblasts stimulated by specific antigen were not cytotoxic to the oligodendrocytes. These findings suggest that oligodendrocytes might be target cells for MBP-reactive lymphocytes in EAE if antigen presentation is appropriate.