Reaginic antibody to contact sensitizing agents. Occurrence of cells which supress IgG and not reagin responses.

Mice painted with the contact sensitizing agent picryl chloride produce IgG and reaginic or IgE-type antibody. They concomitanly produce suppressor cells which can inhibit IgG responses of normal mice to picryl chloride. These cells were produced between 3 and 7 days after primary sensitization (skin painting) and were T cells, as evidenced by their sensitivity to anti-theta serum and by their passage through nylon wool columns. Although they inhibited IgG responses they did not significantly change IgE titres. This correlates with a previous observation that repeated painting with picryl chloride increased IgE and not IgG responses.