ANTIGENIC RELATIONSHIP BETWEEN THE ALPHA-CHAIN OF C-3, A LEUCOCYTE-SURFACE ANTIGEN INVOLVED IN THE ACTIVATION OF PHAGOCYTIC-CELLS, AND A 50,000 MW B-CELL ANTIGEN

  • 1 January 1985
    • journal article
    • research article
    • Vol. 54  (4) , 791-800
Abstract
A monoclonal antibody, M522, reacting with human monocytes, neutrophils and a proportion of non-adherent PBL in a pattern similar to OKM-1 and anti-Mo-1, and pecipitating a dimer of MW 165,000 and 100,000 from neutrophils, was shown to react with C3 at an epitope localized on the .alpha.-chain of C3. F(ab)2-fragment of M522 stimulate the respiratory burst of neutrophils and monocytes. M522 differs from 2 monoclonal antibodies against the Mo-1 molecule with respect to the capacity to inhibit the binding of sheep erythrocytes coated with different C3-fragments to C-receptor carrying cells. It inhibited the binding of H-coated particles to B-lymphoid cells and precipitated a 50,000 MW molecule from RAJI cells and tonsil lymphocytes. The results obtained suggest an antigenic relationship between the .alpha.-chain of C3, the H-chain of a membrane molecule involved in neutrophil/monocyte activation, and a B cell molecule of MW 50,000.