Recognition of human T cell leukemia virus type I (HTLV-I) gag and pX gene products by MHC-restricted cytotoxic T lymphocytes induced in rats against syngeneic HTLV-I-infected cells.

We established rat T cell lines expressing human T cell leukemia virus type I (HTLV-I) Ag from inbred strains of rats, WKA/H, DA, and F344, to study CTL response against the HTLV-I-infected cells. HTLV-I-specific Ag expressed in these rat cells were HTLV-I gag Ag, p19, p24, and p15, and pX Ag, p40tax and p27rex, but not env Ag, as determined by immunofluorescence and immunoblot assays. By immunization of rats with syngeneic HTLV-I-infected cells, CTL against syngeneic HTLV-I-infected cells and antibodies to HTLV-I Ag were generated in WKA/H and DA rats. The bulk CTL cultures from WKA/H and DA rats lysed specifically syngeneic SV40-transformed kidney cells infected with recombinant vaccinia viruses (RVV) expressing HTLV-I gag and pX Ag, but not those infected with RVV expressing HTLV-I env Ag or a control vaccinia virus. From WKA/H rat CTL cultures, four CTL clones reactive with syngeneic HTLV-I-infected cells were isolated, three of which were specific for p27rex/p21x, but the Ag recognized by the other CTL clone was not defined with any RVV used. These results indicate that HTLV-I gag and pX gene products are recognized by MHC-restricted rat CTL specific for syngeneic HTLV-I-infected cells.