Effect of low-molecular-weight lymphokine components on the Fc and C3b receptor-mediated macrophage functions.
Rat lymphokine (LK) components of 500--2500 MW separated on Sephadex G-15 column (FrA) were tested for their effect on Fc and C3b receptor activities of rat resident (rPM) and thioglycollate-provoked (pPM) peritoneal macrophages. Functions of the receptors were studied by measuring the adherence and uptake of 51Cr-labeled sheep red blood cells (SRBC) mediated by isolated rat anti-SRBC IgM or IgG2a antibodies and human C3, respectively. On rPMs mainly Fc mu receptors (Fc mu Rs) were affected by FrA; at low concentration (20 micrograms/ml) adherence was increased and phagocytosis was inhibited. At higher concentrations (40-80 micrograms/ml) a reverse effect was observed: adherence was inhibited and phagocytosis increased. On pPMs IgG2a-mediated functions were mainly affected by FrA with a concentration dependence like that observed with Fc mu Rs on rPM monolayers. A concentration-dependent enhancement of C3b receptor (C3bR)-mediated adherence by FrA was observed on both PM types. On pPms C3bR-mediated phagocytosis was enhanced as well.
D000818:Animals; D005591:Chemical Fractionation; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D008222:Lymphokines / Q000502:physiology*; D008262:Macrophage Activation; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D008297:Male; D008970:Molecular Weight; D010587:Phagocytosis; D051381:Rats; D011919:Rats, Inbred Strains; D011951:Receptors, Complement / Q000378:metabolism*; D017463:Receptors, Complement 3b; D011961:Receptors, Fc / Q000378:metabolism*; D012397:Rosette Formation
D007074:Immunoglobulin G; D007075:Immunoglobulin M; D008222:Lymphokines; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D011961:Receptors, Fc