Anti‐NA. An Antibody Sub‐dividing Melanesian N

摘要

Abstract.An antibody has been encountered occurring naturally in two healthy untransfused male Melanesian blood donors, the specificity of which is directed against a part of the N antigen. The effect is demonstrable with Melanesian but not so far with Caucasian red cell samples. Against the latter, the antibody acts as anti‐N, with a pronounced dosage effect, whereas a proportion of N‐containing Melanesian bloods fail to react. There are indications that the same may hold good for some American Negroes and South American Indians.The antibody may be ‘new’, or may possibly be the same as the ‘anti‐N’ reported on two occasions as occurring in MN individuals, but not acting as an auto‐agglutinin.The antibody has been designated anti‐NA, the corresponding part of the N antigen NA, and cells lacking this specificity Na. It has not proved possible to separate any component having the properties of anti‐NAfrom five human and one rabbit anti‐N sera, and these sera failed to distinguish NAfrom Nacells.Family studies on Melanesians show that NAappears to be inherited in a straightforward manner. The proportion of NN Melanesians who lack NAvaries between 10 and 30% in different ethnic groups, in one of which there is a hint of significant association between S and NA. The varying ITcontent of Melanesian bloods does not enter into