Spontaneous T cell proliferation of wild-type or hsp60-transgenic NOD mice to hsp60 peptides. Groups of six 2-month-old mice were tested individually for spontaneous reactivity to hsp60 peptides p278, p277, and MT-p278, and to no added peptide (control). Compared with wild-type NOD mice, the Eα.hsp60 NOD transgenics manifest a lack of spontaneous T cell reactivity to the self-hsp60 peptide p277, but their spontaneous T cell reactivity to a foreign T-cell epitope in NOD mice (18), the mycobacterial hsp60 peptide MT-p278, is not diminished. The mouse homologue of MT-p278, p278, is not a T cell epitope in NOD mice.