Lipopolysaccharide significantly enhances erythrophagocytosis but marginally stimulates the phagocytosis of Staphylococcus aureus in mouse peritoneal macrophages

Studies on the accumulation of serum proteins in zymosan-induced inflammation in mouse peritoneum

Inflammatory responses were induced in mice by intraperitoneal (i.p.) injection of zymosan. This resulted in a rapid accumulation of protein in the peritoneum that was dependent on the time of the injection and concentration of zymosan used. Though other stimuli, e.g., phorbol myristate acetate, lipopolysaccharide, carrageenan and latex beads, caused the accumulation of proteins, the maximum response was obtained only with zymosan. Injection of free fatty acids were unable to induce protein accumulation in peritoneum. Factors which decreased leukotriene production in mouse peritoneum, i.e., dietary n-3 fatty acids essential fatty acid deficient diets, did not affect protein accumulation. Direct injection of leukotrienes also failed to induce protein accumulation. Analyses revealed that the proteins were similar to serum proteins, indicating that zymosan causes the leakage of serum proteins into peritoneum.

Anemia and anti-erythrocyte antibodies developed after repeated injections of sonicated preparations of Plasmodium berghei and Babesia rodhaini

Anemia developed in mice after repeated injections of sonicated preparations of Plasmodium berghei and Babesia rodhaini. Anti-erythrocyte antibodies were detected in sera by an enzyme-linked immunosorbent assay and their levels rose as anemia developed. Administration of carbon particle suspension to block the mononuclear phagocyte system was effective to inhibit anemia induced by injections of sonicated parasite preparations. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting analyses were carried out to examine autoantigens on the surface of the erythrocyte membrane reacting to anti-erythrocyte antibodies. The anti-erythrocyte antibodies from mice injected with the sonicated P. berghei preparations bound specifically to three components of the erythrocyte membrane. The anti-erythrocyte antibodies produced by the sonicated B. rodhaini preparations also reacted with four components, two of which corresponded to those reacting after the injection of the sonicated P. berghei preparations. These results suggest that both P. berghei and B. rodhaini organisms have some materials capable of inducing production of the anti-erythrocyte antibodies which mediate erythrophagocytosis by macrophages of the mononuclear phagocyte system during Plasmodium and Babesia infections.

Inhibition of macrophage phagocytosis in cryptococcosis: phenotypic analysis of the suppressor cell

Our laboratory has previously reported a suppressor cell mechanism to occur late in the course of a lethal infection with Cryptococcus neoformans. A soluble factor was found to be responsible for inhibition of the phagocytic activity of a subpopulation of peritoneal macrophages. The suppressor cell was identified as a T cell which required in vitro stimulation with specific antigen before the phagocytosis-inhibiting lymphokine (PIL) was produced. PIL action was allospecific and occurred in animals given tolerogenic doses of cryptococcal and noncryptococcal antigens. The current investigation has further characterized the T lymphocyte responsible for PIL activity. The suppressor cell was found to be in a cyclophosphamide-sensitive pathway. PIL activity was not detected when spleen cell populations were treated with anti-I-J and complement or anti-Lyt-2 and complement. Likewise, a mixture of anti-I-J-treated and anti-Lyt-2-treated cells was incapable of synthesizing the lymphokine. Treatment of spleen cells with anti-Lyt-1.2 or anti-L3T4 and complement did not eliminate PIL synthesis. Further analysis of the genetic restrictions associated with the PIL-macrophage interaction revealed regulation by the I-J subregion of the major histocompatibility complex.

Preliminary studies on the inflammatory stimulus induced proteins in mouse resident peritoneal macrophages

Chemotaxis, release of lysosomal enzymes, synthesis of eicosanoids and phagocytosis are some of the important functions mediated by macrophages. Active protein synthesis have been implicated as an essential step in the mediation of these vital physiological functions. The proteins synthesized during the inflammation with microbial agents have not been identified. In the current investigation, we report the synthesis of five proteins of molecular weights 72,000; 70,000; 40,000; 34,000; and 32,000 in mouse peritoneal macrophages after incubation with inflammatory stimuli derived from microorganisms. A possible role for these proteins in phagocytosis was suggested.