Production of antigen-specific suppressive T cell factor by radiation leukemia virus-transformed suppressor T cells.

Hen egg-white lysozyme (HEL)-specific suppressor T cells induced in C57BL/6 mice have been selected by sequential passage over plates coated with goat anti-mouse Ig and HEL. These suppressor T cells, 80% I-J+, were infected in vitro with radiation leukemia virus (RadLV/Nu1) and injected intravenously into sublethally irradiated syngeneic recipients. After 4-6 months, 6 out of 20 injected mice developed thymic lymphomas, which were maintained by transplantation into histocompatible hosts and subsequently established as permanent cell lines. Cells of these six thymomas were screened for the presence of Thy 1.2, Lyt 1, Lyt 2, I-Jb, and Ig cell surface antigens by direct or indirect immunofluorescence. One tumor (thymoma L4) was found to express the expected phenotype of suppressor T cells (Thy 1.2+, Lyt 2+, I-J+). High-speed supernatants of extracts obtained from L4 cells were able to induce HEL-specific suppression in a T cell proliferative assay, demonstrating the presence of an antigen-specific suppressive T cell factor.