OBJECTIVETo observe the effects of lipopolysaccharides of Bacterium prodigiosum (BP-LPS) in inhibiting tumor growth and improving immunosuppression in mice.

METHODSIn mice bearing S180 tumor and a mouse model of immunosuppression induced by cyclophosphamide (CTX), the tumor growth, indexes of the immune organs and peripheral white blood cell count were measured after intraperitoneal injection of BP-LPS.

RESULTSInjections of BP-LPS (40 U/kg) for 8 consecutive days resulted in a significant inhibition of the tumor growth in mice bearing S180 tumor (P<0.01), with a dose-dependent increase of the spleen indexes but no obvious changes in the thymus indexes. Intraperitoneal injections of BP-LPS for 7 days inhibited the reduction of peripheral white blood cells and spleen indexes in immunosuppressive mice, but did not produce any significant changes in normal mice.

CONCLUSIONBP-LPS can inhibit the tumor growth in tumor-bearing mice and enhance the immune functions of immunosuppressive mice.