Phagocytosis of senescent erythrocytes by autologous monocytes: Requirement of membrane-specific autologous IgG for immune elimination of aging red blood cells

Naturally occurring anti-band-3 antibodies and complement together mediate phagocytosis of oxidatively stressed human erythrocytes.

“…Antibodies to erythrocyte membrane constituents are present in normal human serum (1)(2)(3)(4)(5). Some of them opsonize senescent or damaged erythrocytes and induce engulfment of the cells by phagocytes (3)(4)(5).…”

“…Some of them opsonize senescent or damaged erythrocytes and induce engulfment of the cells by phagocytes (3)(4)(5). One of them, a naturally occurring autoantibody to band 3 protein of erythrocyte membranes (anti-band-3), reacts with exoplasmic and cryptic domains of this protein (2).…”

“…This evidence is, however, not conclusive because the amount of IgG bound to senescent erythrocytes (8)(9)(10) is not sufficient to elicit IgG Fc receptormediated phagocytosis, which requires thousands of IgG per cell (11,12). Furthermore, antibodies with specificities other than anti-band-3 also recognize senescent erythrocytes (4,5). The functional role of naturally occurring anti-erythrocyte antibodies has been studied by opsonizing erythrocytes with purified antibodies in the absence of serum (3)(4)(5).…”

“…Furthermore, antibodies with specificities other than anti-band-3 also recognize senescent erythrocytes (4,5). The functional role of naturally occurring anti-erythrocyte antibodies has been studied by opsonizing erythrocytes with purified antibodies in the absence of serum (3)(4)(5). These conditions cannot differentiate between erythrophilic (13,14) and antigen binding of added IgG.…”

Senescent Cell Antigen: A Terminal Differentiation Antigen

“…Other investigators have confirmed the presence of IgG on senescent, damaged and stored red cells [1,4,16,20,41,42,61,65,68,69]. IgG has been demonstrated on the surface of senescent and stored red cells [20,69] using l25I-labeled anti-IgG.…”