title: My 43, a monoclonal antibody that reacts with human myeloid cells inhibits monocyte IgA binding and triggers function.
abstract: A mAb My 43 of the IgM isotype was obtained from a fusion of spleen cells immunized against human monocytes. This mAb inhibited monocyte binding of both soluble FITC-labeled IgA and IgA-coated E, whereas it did not inhibit IgG binding. The Ag recognized by My 43 was induced on HL-60 cells in parallel with IgA binding ability by 1-25 dihydroxy-vitamin D3 treatment. Phagocytosis of IgA-coated E by monocytes and 1-25 dihydroxyvitamin D3-treated HL-60 cells was inhibited by My 43. Furthermore, a heteroantibody of My 43 x F(ab)'2 anti-E promoted phagocytic uptake of E by monocytes. Production of superoxide anion by IFN-gamma treated U-937 cells was stimulated by My 43 but not by other IgM mAb recognizing myeloid cells. By these criteria My 43 recognized a molecule capable of triggering function. Moreover, its binding reactivity, ability to block binding of IgA and IgA-complexes, and its ability to induce activation of IgA receptor bearing myeloid cells, are consistent with the possibility that My 43 reacts with the IgA receptor on these cells.
authors.affiliation: Department of Microbiology, Dartmouth Medical School, Hanover, NH 03756.
authors.forename: L
authors.initials: L
authors.lastname: Shen
authors.forename: R
authors.initials: R
authors.lastname: Lasser
authors.forename: M W
authors.initials: MW
authors.lastname: Fanger
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D001666:Binding Sites, Antibody; D001667:Binding, Competitive; D002460:Cell Line; D002999:Clone Cells / Q000032:analysis; D003432:Cross-Linking Reagents; D004912:Erythrocytes / Q000276:immunology; D006801:Humans; D006825:Hybridomas / Q000032:analysis; D007070:Immunoglobulin A / Q000378:metabolism*; D051379:Mice; D008807:Mice, Inbred BALB C; D009000:Monocytes / Q000276:immunology* / Q000378:metabolism; D010587:Phagocytosis; D011961:Receptors, Fc; D011971:Receptors, Immunologic / Q000276:immunology*; D012397:Rosette Formation; D013481:Superoxides / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D003432:Cross-Linking Reagents; C045281:IgA receptor; D007070:Immunoglobulin A; D011961:Receptors, Fc; D011971:Receptors, Immunologic; D013481:Superoxides