Re-appraising Rhesus Antigens

Abstract

IMMUNOLOGY Proteins collectively referred to as Rhesus blood group antigens, have become familiar for the threat they pose to developing fetuses. This arises when the immune system of a mother lacking Rh antigens becomes exposed to paternal Rh antigens expressed by the fetus, eliciting a potentially lethal antibody response. Decades after the first immunological description of Rh antigens, Marini et al . assign a possible physiological role for these proteins in the transport of ammonium ions. Earlier studies had identified sequence homology between Rh genes, which encode polypeptide complexes expressed on red blood cells, and ammonium transport proteins (Mep) in yeast. On this basis, Marini et al . tested the ability of Rh genes to complement Mep-deficient yeast mutants, with the result that expression of Rh polypeptides restored the ability of these cells to grow with ammonium sulfate as the sole source of nitrogen. — SJS Nature Genet . 26 , 341 (2000).