Heat-shock proteins expressed on the surface of human T cell leukemia virus type I-infected cell lines induce autoantibodies in rabbits.

Eight human T cell leukemia virus type I (HTLV-I)-infected cell lines were derived in vitro from peripheral blood mononuclear cells of 8 rabbits. Each rabbit was then inoculated with its own HTLV-I-transformed cells, after which all but 1 rabbit had anti-heat-shock protein (hsp) antibodies in sera. Cell line RH/K34, which failed to raise a response to hsp70, caused lethal leukemia when > 2 x 10(8) live cells were injected into unrelated outbred rabbits. Rabbits injected with cell-free virus isolated from RH/K34 cells produced anti-hsp70 antibodies and became infected but developed no fatal disease. ELISA inhibition and flow cytometry analyses indicated that hsp molecules are expressed on the surface of RH/K34 and RH/K30, a nonlethal HTLV-I cell line used for comparison; surface hsp expression does not occur normally. Two proteins of approximately 72 and 93 kDa were detected by Western blot in extracts of RH/K30 cells. Presence of anti-hsp70 antibodies correlated with resistance to lethal doses of live RH/K34 cells, suggesting that hsp immunity may influence the outcome of RH/K34 pathogenicity.