Antibody-mediated suppression of grafted lymphoma. IV. Influence of time of tumor residency in vivo and tumor size upon the effectiveness of suppression by syngeneic antibody.

In the suppression of the growth of a mouse lymphoma 6C3HED by antibody, the effectiveness of antibody in suppressing growing or established tumor cells and comparable number of freshly injected tumor cells is quantitatively similar. The effectiveness of antibody diminishes markedly when the number of tumor cells per mouse reaches the level of 10(6) due to the development of a macrophage shortage. At the 10(5) tumor cells level, antibody-mediated suppression takes place in an optimal manner and between 10(5) and 10(4) tumor cell numbers, the amount of antibody required to suppress 50% of the tumor cells is directly proportional to the number of tumor cells suppressed.