Properties of cloned T cells that mediate delayed-type hypersensitivity against ovalbumin in mice

Cloned T-cell lines that mediate delayed-type hypersensitivity (DTH) against soluble protein antigen, ovalbumin (OA), were established in (C57BL/6 X DBA/2)F1 mice and their properties were examined. They induced antigen-specific delayed-type footpad reactions, characterized histologically by a predominant mononuclear cell infiltration, when transferred intravenously into syngeneic mice. Morphologically, they were medium or large lymphoblasts with granules in the cytoplasm and expressed Lyt 1 cell surface antigens. One of them proliferated antigen specifically under the presence of both C57BL/6 and F1 accessory cells, while others proliferated antigen specifically only under the presence of F1 accessory cells. They also produced macrophage-activating factor (MAF) and substances which mediate a DTH-like footpad inflammatory reaction with a maximum 6 hr after injection into the footpad of normal mice, when incubated in the presence of specific antigen and specific accessory cells in a serum-free medium for 24 hr. These results demonstrate that cloned DTH-effector T cells, established here against soluble protein antigen, are Lyt 1-positive, large lymphoblasts and that they produce MAF and footpad-reactive inflammatory substances antigen specifically under the presence of specific accessory cells.