Second Locus HL-A Antigens and 4a or 4b

Abstract

A panel of over 100 individuals was tested against several 4a and 4b antisera. A 4a/4b type was assigned to each individual on the basis of overall reactions with each group of sera. Because 4a and 4b antisera rarely give identical reaction patterns, the use of several sera in each group gave a better definition of the specificities. The relationship between each 2nd locus HL-A specificity and 4a or 4b was assessed. Most of the narrower antigens showed complete inclusion within 1 group, but there were some anomalies. Associations of these specificities were analyzed further by absorption experiments. Antisera to 4a and 4b were able to define differences in some 2nd locus specificities which were not picked up by the narrower antisera. It seems likey that 4a and 4b represent a separate public site on the HL-A gene product which is multifactorial. For a full description of the antigens, all factors should be stated as there is not an invariant association between components.