IN-VITRO INDUCTION OF CYTOTOXIC T-LYMPHOCYTES AGAINST HTLV-I-INFECTED T-CELLS FROM ADULT T-CELL LEUKEMIA PATIENTS, ASYMPTOMATIC HTLV-I CARRIERS AND SERONEGATIVE HEALTHY DONORS

We investigated an in vitro method to produce cytotoxic T lymphocytes (CTLs) against HTLV-I-infected T-cells using peripheral blood mononuclear cells (PBMC) of adult T-cell leukemia (ATL) patients, asymptomatic HTLV-I carriers (AC) and seronegative healthy donors. The PBMC were restimulated repeatedly for 4 weeks with HLA-matched HTLV-I-infected T-cells which had been pretreated at 56 degrees C for 30 min to inactivate infectious HTLV-I. The culture medium included 10-100 units/ml of recombinant lymphokines (rIL-1, rIL-2, rIL-4, rIL-6 and rIL-7) and 10% fetal calf serum in RPMI-1640 medium, The cytotoxic activity was measured against HLA-matched HTLV-I-infected T-cell lines after CD4(+) or CD8(+) cells were positively panned from the cultured PBMC. The PBMC of ATL, AC and healthy donors were able to produce either CD4(+) or CD8(+) CTLs against HTLVI-related antigens (env, gag, p21(chi), p27(rex) and p40(tax)) as well as the antigen(s) of as-yet unknown specificity expressed on HTLV-I-infected T-cells. All the CTLs recognized the specific antigens in the context of either class I or class II HLA types. These results indicated that ATL patients, AC and healthy donors were immunocompetent to generate CTLs against HTLV-I-infected T-cells and probably against HTLV-I-transformed T-cells.