Autoreactive T cells from normal mice recognize mycobacterial 65 kd heat-shock protein from mycobacterium bovis

We established a TCR V_β6⁺ CD4⁺ autoreactive T cell line from lymph nodecells of unprimed BALB/c mice bred in a specific pathogen-free condition. The T cell line proliferated In the presenceof Irradiated spleen cells expressing MHC class II I-A_d and/or I-E^d molecules. The proliferatlveresponse of the autoreactive T cell line was significantly enhanced In response to 65 kd heat-shock protein (hsp) from Mycobacterium bovis, a member of the hsp60 family, which is highly conserved in both prokaryotes and eukaryotes. Our results suggest that the autoreactive T cells in normal mice may recognize endogenous peptldes of self-hsp60 bound to MHC class IIgene products and are cross-reactive to mycobacterial 65 kd hsp. The autoreactive hsp-specific T cells may therefore play an important role in the immune surveillance against invasion of various pathogens and tumors by recognizing Infected and transformed autoiogous cells that express high levels of endogenous hsp60.