Depressed chemotactic responses in vitro of peritoneal macrophages from tumor-bearing mice.

The in vitro chemotactic responses of peritoneal macrophages from mice bearing transplantable syngeneic 3-methylcholanthrene-induced tumors in their footpads were depressed to about 50% of normal levels. This chemotactic defect to both lymphocyte- and complement-derived stimuli was evident before the appearance of palpable tumor (within 1 week of tumor injection) and persisted until the death of the animal by 6-8 weeks. Chemotactic depression was not observed with macrophages from mice treated with tissue culture medium, fetal calf serum, incomplete Freund's adjuvant, or syngeneic spleen cells.