HLA-and Gm-linked genes affecting the degradation rate of antigens (sheep red blood cells) endocytized by macrophages.

Phagocytosis and catabolism of sheep red blood cells by human peripheral blood phagocytes were studied in 100 normal caucasoid subjects (44 males and 56 females). Both phenomena are highly reproducible, and their indices seem to be biological constants. There is no correlation between these two indices and the indices do not have a correlation with ABO or Rh markers. Further, the phagocytic index has no correlation with HLA and GM markers. However, a low speed of degradation is significantly correlated (p = 0.001) with the HLA-DR3 antigen, and most of the low degraders are significantly correlated (p = 0.006) with both DR3 and Gm 3,23,11 (probably Gm homozygous). Thus the gradient of antigen degradation could be related to an interaction between MHC and Gm immunoglobulin genes, as is found in the mouse [Biozzi's high (H) and low (L) responder strains.