Receptors for IgG Fc and complement in the mammalian aorta

The presence of IgG Fc receptors in the tissue sections of aorta and aortic valves of man, ox and pig was demonstrated by means of hemadsorption of human and rabbit IgG antibody sensitized erythrocytes to these sections. C3b receptors in the tissue sections of aortic valves of these three mammals were also demonstrated by using sheep erythrocytes sensitized with rabbit IgM antibody which bound murine complement. 8 of 13 systemic lupus erythematosus sera and 2 of 19 other collagen disease sera were shown to be able to inhibit the adsorption of rabbit IgG antibody sensitized erythrocytes to the human aortic sections upon preincubation of the tissues with the pathologic sera. The amount of immune complexes in the 'inhibition-positive' sera was significantly higher than that in the negative sera.