Tumor cell cytostasis by macrophages and antibody in vitro. I. Resolution into contact-dependent and contact-independent steps.

In a murine system, macrophages, in concert with antibody, were shown to suppress iododeoxyuridine incorporation by tumor cells. The mechanism of suppression did not involve phagocytosis or lysis. The generation of suppressed tumor cells was resolved into a contact-dependent step and a contact-independent step. The first step was one-hit with respect to macrophages and multi-hit with respect to antibody.