Studies on cell surface antigens of mouse leukemic and normal lymphocytes. IV. Functional studies on mouse T lymphocyte subpopulations. B. Lyt phenotype of cytotoxic T lymphocytes and their precursors in B6-Lyt-1.1 mice.

Lyt phenotype of in vitro generated alloreactive cytotoxic T lymphocytes (CTL) and their precursors in B6-Lyt-1.1 (Thy-1.2, Lyt-1.1, Lyt-2.2) congenic strain of mice was studied. The generation of CTL in vitro was completely abrogated by pretreatment of responder cells with antisera to Thy-1.2, Lyt-1.1 and Lyt-2.2 antigens and complement. Mixing of anti-Lyt-1.1-pretreated cells with anti-Lyt-2.2-pretreated cells did not restore CTL generation indicating that both Lyt antigens are expressed on the same precursor cell population. The effect of anti-Lyt sera was specific because the generation of CTL was prevented only when cells from strains possessing appropriate Lyt alleles were pretreated. CTL were eliminated by lysis with anti-Thy-1.2 serum and strongly reduced by anti-Lyt-1.1 and anti-Lyt. 2.2 sera. Nevertheless, a small but significant proportion of CTL was insensitive to lysis with anti-Lyt sera. These data indicate that a phenotype of precursor cells and of majority of CTL is Thy-1.2+ Lyt-1.1+ Lyt-2.2+.