Development of an antigen-specific CD8 suppressor effector clone in man.

A long-term cultured IL-2-dependent keyhole limpet hemocyanin (KLH)-specific CD8 (T8) suppressor clone (5B9) was generated from a healthy donor hyperimmunized with KLH. The 5B9 clonal population suppressed in vitro anti-KLH antibody response but did not suppress anti-TT antibody response or PWM-driven IgG synthesis. Moreover, 5B9 cells could not suppress anti-TT antibody response even in the presence of free KLH. 5B9 cloned cells suppressed the anti-KLH antibody response of B cells cultured with CD4+4B4+ cells without requiring the presence of CD8+ cells. This KLH-specific CD8 suppressor clone is an effector type rather than an inducer type of suppressor T cell. The cloned cells expressed alpha- and beta-TCR proteins (defined by WT-31 antibody) on their cell surface. More importantly, the CD3:TCR complex was functionally important in the suppression induced by this clone, because after CD3 antigen modulation from its cell surface, the suppressor effector function was abolished.