Establishment and functional analysis of a cloned, antigen-specific suppressor effector T cell line.

A long-term cultured suppressor T cell line (3D10) was established from the spleen cells of KLH hyperimmunized C3H mice. The cells of 3D10 suppressed the secondary antibody response against dinitrophenylated KLH both in vitro and in vivo. The 3D10 cells were capable of directly suppressing the antibody response mounted by B cells and Lyt-1+2-helper T cells without participation of Lyt-1+2+ cells, which indicates that 3D10 is an effector rather than an inducer-type suppressor T cell. The cell line was unable to suppress the response against DNP-FGG even in the presence of free KLH. By analysis with a fluorescence-activated cell sorter, 3D10 was found to bear determinants detectable by conventional anti-Ia as well as rabbit anti-VH. The Ia locus was mapped in the I-J subregion and was detected by either conventional or monoclonal anti-I-J antibodies. The I-J determinants detected by monoclonal antibodies were different from those expressed on inducer-type suppressor T cells. The cell line also bears an antigenic determinant detected by a monoclonal SJL anti-SJA/9 antibody (HA16) that recognizes an allotypic determinant on T cells linked to the immunoglobulin heavy chain locus. The results indicate that the cell line 3D10 represents a suppressor effector T cell that acts directly on carrier-specific helper T cells.