PATTERNS OF REACTIVITY OF EPSTEIN-BARR VIRUS-SPECIFIC T-CELLS IN A-TYPE DONOR CULTURES AFTER REACTIVATION WITH AUTOLOGOUS A-TYPE OR B-TYPE TRANSFORMANTS

Regression endpoints were assessed in cultures from 11 Epstein-Barr (EB) virus A-type sero-positive donors and 2 seronegative donors using A- and B-type EB virus preparations. In 9 11 of the seropositive donors, the resulting endpoints using A-type or B-type virus were similar and demonstrated a significant T cell response to both virus types. However, the regression endpoints for 2 11 seropositive donors were reproducibly higher with B-type virus compared with A-type virus, indicating a weak T cell response to the B-type virus compared with that to the A-type virus. Seronegative donor cultures showed no regression. The patterns of reactivity of bulk cultures of EB virus-specific cytotoxic T cells and T cell clones from selected seropositive donors were compared. Four of six donors showed evidence of a cytotoxic T cell response to A- and B-type autologous transformants while cytotoxic T cells from 2 6 donors (corresponding to those identified as lacking regression to B-type virus) lysed autologous targets infected with A-type but not B-type virus. The results show that while most A-type seropositive donors are capable of mounting a T cell response to A- and B-type virus, certain donors apparently lack B-type reactivity. © 1990.