Immune Response to Gross Virus-induced Lymphoma. I. Kinetics of Cytotoxic Antibody Response2

Abstract

The kinetics of the humoral immune response to a transplantable tumor induced by Gross virus in W/Fu rats, (C58NT)D, was studied. Eight-week-old W/Fu rats were given subcutaneous injections of varying doses of tumor cells and bled serially for determination of cytotoxic antibody levels. In 65% of the rats, small tumors arose which regressed within 2 weeks. The antibody response was biphasic: an initial peak at 10 days followed by a second peak at about 30 days. In the other rats, tumors either regressed after a longer period of growth or they grew progressively. The initial antibody response was similar to that of the early regressor animals, but this was followed by higher second-peak filers that remained elevated for longer periods. The height of the second antibody peak was closely related to the number of tumor cells injected. Inoculation of a second dose of tumor cells resulted in a boost in antibody titers and persistence of high titers for 2 weeks beyond that of the unboosted controls. Fractionation of sera on Sephadex G-200 showed that the antibodies in the first-peak sera were 19S in size, and those in second-peak sera were 7S.