Band-3 polymers and aggregates, and hemoglobin precipitates in red cell aging

As part of our systematic ongoing studies of mechanisms of cellular and molecular aging, we developed a "biochemical profile" of senescent human red cells. This "red cell aging" panel allows us to assess functional red cell age independent of chronologic age. The panel used to obtain this profile includes IgG binding, phagocytosis, enzyme activity, anion transport, ankyrin binding, and immunoblotting with antibodies to band 3. We used this panel to compare the biochemical profile of glucose 6-phosphate dehydrogenase-deficient and hemoglobin Köln cells containing high molecular weight protein polymers or hemoglobin precipitates with that of normal senescent cells. We found no evidence in support of the concept that aggregation of band 3 plays a role in the mechanism for generating senescent cell antigen. Observations such as these support the hypothesis that degradation of band 3, rather than aggregation is a critical event in IgG binding and normal erythrocyte aging.