The ability of immuno globulin a to inhibit complement consumption by complement fixing antigens and antigen antibody complexes
Australian Journal of Experimental Biology and Medical Science 62(1): 1-10
ISSN/ISBN: 0004-945X Accession: 006594261
The polymeric and monomeric (7S) forms of the nitrophenyl-specific [murine plasmacytoma] MOPC-315 IgA myeloma protein were examined for their capacity to inhibit the consumption of guinea pig complement (C) by the C-activating protein DNP46BSA [2,4-dinitrophenylated bovine serum albumin] and by antigen-antibody (Ag-Ab) complexes. On a molar basis, 13S IgA was slightly (2- to 3-fold) more efficient than 7S IgA in inhibiting C consumption by DNP-BSA. When mixed with IgG antibodies prior to incubation with a non-complement-fixing antigen (TNP-KLH [2,4,6-trinitrophenylated-keyhole-limpet hemocyanin]), 13S IgA was considerably more effective than 7S IgA in preventing the formation of Ag-Ab complexes able to fix C. The degree of inhibition observed was related to the concentrations of C used in the assay, being greater at lower C concentrations.