The growth of WEHI-3 is inhibited by 4 ng/ml LPS and blocked by higher concentrations. Dextran sulfate at 30 to 40 ng/ml also inhibits growth. Latex beads are phagocytized but are not toxic. Zymosan and BCG are phagocytized and block growth. The cells exhibit only weak effector activity in antibody dependent cell mediated cytotoxicity.