In situ immune complex formation in the mouse glomerulus: reactivity with human IgM rheumatoid factor and the effect on subsequent immune complex deposition.

An in situ model of immune complex formation in the mouse was utilized to study the interaction of human IgM rheumatoid factor (RF) with glomerular bound immune complexes (IC). Prior intravenous injection of RF did not interfere with in situ IC formation, but reacted with complexes once formed. RF injected after formation of in situ IC was deposited in the same distribution as the complexes and was capable both in vivo and in vitro of acting as an immunoabsorbent and binding IC with the same antibody species as the in situ IC, but which had a different antigen component. The potential for this in situ immunoabsorbent activity of RF in the pathogenesis of the chronicity of the lesion in glomerulonephritis is discussed.