title: Effect of macrophage activation on phagocyte-Plasmodium interaction.
abstract: We investigated the effect of both immune and normal sera on the binding of free Plasmodium berghei by resident and activated macrophages. Resident macrophages bound plasmodia to a greater extent than did activated macrophages, regardless of treatment. Resident macrophages bound free plasmodia, predominantly trophozoites, in the presence of normal serum by a mechanism inhibited by N-acetylglucosamine and N-acetylmannosamine. Macrophages activated through treatment with Propionibacterium acnes ("Corynebacterium parvum"), on the other hand, did not bind free plasmodia in the presence of normal serum through systems inhibited by N-acetylmannosamine or N-acetylglucosamine. The binding of free plasmodia by activated macrophages was greatest in the presence of immune serum and could be inhibited by immune complexes but not by N-acetylmannosamine or N-acetylglucosamine. These results suggest that a receptor for a carbohydrate component of a normal serum opsonin mediates initial adherence of plasmodial antigen onto resident macrophages, triggering both the immunological cascade and macrophage activation. After activation, the macrophages no longer have the carbohydrate-specific receptor but do have functional Fc receptors which mediate the adherence of immune-serum-opsonized plasmodia.
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex; D005260:Female; D008262:Macrophage Activation; D016177:Macrophage-1 Antigen; D008264:Macrophages / Q000276:immunology* / Q000648:ultrastructure; D008288:Malaria / Q000276:immunology*; D008297:Male; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D009005:Monosaccharides / Q000378:metabolism; D010587:Phagocytosis; D010962:Plasmodium berghei / Q000166:cytology / Q000276:immunology*; D051381:Rats; D011916:Rats, Inbred F344; D011951:Receptors, Complement / Q000502:physiology; D011961:Receptors, Fc / Q000502:physiology
chemical_list: D000936:Antigen-Antibody Complex; D016177:Macrophage-1 Antigen; D009005:Monosaccharides; D011951:Receptors, Complement; D011961:Receptors, Fc