Mechanisms of Red Cell Destruction Mediated by Non‐Complement Binding IgG Antibodies: the Essential Role in Vivo of the Fc Part of IgG

Abstract

Summary: F(ab′)₂G anti-D was prepared by limited digestion of IgG anti-D with pepsin. Conditions of digestion were chosen in order to obtain a nearly complete conversion of the anti-D antibody molecules as tested by immunochemical and serological techniques. The F(ab′)₂G anti-D was not capable of inducing adherence of rhesus D positive red cells to monocytes in vitro or of eliminating such cells in vivo in normal volunteers. These findings are compatible with a role of the Fc-receptor-mediated adherence to cells of the macrophage system in vivo in the destruction of erythrocytes by non-complement binding IgG antibodies.