title: Antiglobulin serum mediated phagocytosis of normal senescent and oxidized RBC: role of anti-IgM immunoglobulins in phagocytic recognition.
abstract: Fresh human monocytes usually do not recognize normal RBCs; however, in our newly developed assay antiglobulin-opsonized normal RBCs were phagocytized. Both anti-IgG and anti-IgM fractions present in the antiglobulin serum were involved but the major opsonin was anti-IgM. The anti-IgM opsonized mainly senescent RBCs and therefore could be used to discriminate young from senescent RBCs. The antiglobulin serum and monospecific anti-IgM increased opsonization of in vitro oxidized and desialylated RBCs, whereas trypsin-treatment of RBCs decreased phagocytosis. The material removed by trypsin from the RBCs surface inhibited the antiglobulin and monospecific anti-IgM phagocytic assay supporting the view that membrane associated elements crossreacted with anti-IgM. These results suggest that both internal cellular events and external removal of sialic acid play a role in the emergence of non-IgG covered epitopes on the surface of senescent and oxidized erythrocytes.
mesh_terms: D000888:Antibodies, Anti-Idiotypic / Q000276:immunology*; D004905:Erythrocyte Aging; D004912:Erythrocytes / Q000276:immunology*; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology; D007075:Immunoglobulin M / Q000276:immunology*; D009000:Monocytes / Q000276:immunology*; D009895:Opsonin Proteins / Q000276:immunology*; D010084:Oxidation-Reduction; D010587:Phagocytosis
chemical_list: D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D009895:Opsonin Proteins