Cytotoxic effects of myelin basic protein-reactive T cell hybridoma cells on oligodendrocytes

Cells of a rat/mouse T cell hybridoma reactive to the encephalitogenic peptide of myelin basic protein (MBP) was found to be cytotoxic to 51Cr-labelled rat oligodendrocytes (oligos) inducing 52 +/- 5% 51Cr release vs. 28 +/- 2% spontaneous 51Cr release from replicate oligos. The hybridoma cells were not toxic for rat astrocytes or concanavalin A-stimulated lymphoblasts. Hybridoma T cells reactive to an experimental allergic encephalomyelitis-irrelevant antigen (ovalbumin) were not cytotoxic to oligos. The cytotoxic reaction required cell-cell contact but did not require the in vitro presence of antigen-presenting cells MBP. The target antigen on the oligos is not yet defined. These studies suggest that MBP-reactive T cells can be directly cytotoxic to oligos in the absence of other cell populations.