Antibody Production and Interaction with Lymphoid Cells in Relation to Tumor Immunity in the Moloney Sarcoma Virus System

The temporal development of antibodies to Moloney sarcoma virus (MSV)-induced antigens in relation to tumor progression was followed with the membrane immunofluorescence (MF) and antibody-dependent normal lymphocyte cytotoxicity (ADNLC) assays. Antibody was detected at 14 days following virus infection by MF. In mice that developed primary tumors which regressed, MF titers developed to high levels following a period between 2 and 4 weeks post-innoculation during which the titers remained at low and constant levels. The increase in MF titers corresponded closely on a temporal basis to the initiation of the regression process. In contrast, antibody remained at low levels in those mice that developed progressively growing tumors. ADNLC was detected in the sera of regressor mice approximately 6 weeks post-inoculation but was not detectable at any of the time interavals in sera from mice with progressively growing tumors. Attempts to enhance the cytotoxic activity of normal spleen cells directly with immune serum were unsuccessful. The synergistic effect of serum on the cytotoxic activity of immune lymphocytes was less pronounced than with normal lymphocytes in this system. Temporal studies indicated that there was an inverse relationship between the development of cellular immunity and the capablility of these cells to be activated in the ADNLC assay.