Cellular origin of interferon induced by bacterial lipopolysaccharide.

Bacterial lipopolysaccharide (LPS) induces interferons with different properties in mouse macrophages and B lymphocytes. Macrophage interferon is labile at 56 degrees C and is neutralized by anti-mouse fibroblast interferon at a dilution of 1:6,142. B cell interferon is more heat stable and is neutralized by the same antiserum only at a dilution of 1:276. Serum obtained early (1 h) after an intravenous injection of 100 mug of LPS resembled macrophage interferon, whereas serum obtained at later times resembled more and more B cell interferon. The diverse cellular origin of LPS-induced interferon may explain the broad hyporesponsiveness produced by LPS in animals.