Production of Tumor-Specific Antibody in the Xenogeneic Host: Use of Blocking Antibody

Abstract

Rabbit antisera to normal C57BL/6 spleen cells were produced by repeated weekly injection. The 8-week pooled antiserum was cytotoxic for C57BL/6 splenic lymphocytes and EL4 cells in equal titer. The antiserum was incubated with EL4 ascites cells, and cell-serum suspensions were injected intravenously into rabbits. The antisera resulting from 2, 3, and 4 such weekly immunizations were assayed for cytotoxicity against C57BL/6 splenic lymphocytes and EL4 cells and compared with control sera produced identically, except that normal rabbit serum was substituted for the rabbit antinormal spleen cell serum. The experimental sera resulting from the passive administration of antibody to normal cells had progressively higher titers for EL4 cells and low liters for normal cells. Moreover, while the cytotoxic activity for normal spleen cells was easily abolished by absorption with normal spleen cells, there was little reduction in the cytotoxic titer for EL4 cells, even after exhaustive absorption with normal spleen cells. In the control serum, no cytotoxic antibody was demonstrated after absorption with normal spleen cells. In vivo absorptions substantiated these results. The applicability of these techniques and hypotheses concerning their effectiveness are discussed.—J Natl Cancer Inst 49: 1063–1070, 1972.