Defective tumoricidal capacity of macrophages from P/J mice: characterization of the macrophage cytotoxic defect after in vivo and in vitro activation stimuli.

Unlike macrophages from responsive mouse strains, peritoneal cells of P/J mice treated in vivo with viable Mycobacterium bovis, strain BCG, or killed Corynebacterium parvum fail to develop tumoricidal activity. P/J macrophages treated in vitro with lymphokine-rich supernatants, bacterial endotoxic lipopolysaccharides (LPS) or T cell mitogens also fail to develop cytotoxic activity. Experimental manipulation of effector:target cell ratios, doses of activation stimuli, or tumor target cells did not evoke cytotoxic activity. The macrophage defect of P/J mice appeared similar to that of lipid A-insensitive C3H/HeJ mice. The macrophage defect of C3H/HeJ mice is controlled by a gene identical or closely linked to the Lpsd gene. Tumoricidal defects of P/J macrophages, however, appeared independent of the Lpsd gene: responses of P/J spleen cells or macrophages to LPS, which are controlled by the Lps gene, were normal. P/J mice therefore represent a distinct and potentially useful genetic probe for characterization of mechanisms in macrophage activation.