SEROTYPING FOR HOMOTRANSPLANTATION 28 SIB-PAIR ASSAY FOR NONHL-A ANTIGENS

Summary. Negative results were obtained in an investigation of 118 selected lymphocytotoxic antisera for activity against antigens determined by a locus or loci independent of the HL‐A locus. The sera studied were those not readily identifiable in terms of either generally recognized or tentative HL‐A antigenic specificities, and accordingly were considered appropriate for study to search for nonHL‐A antibodies. It is concluded that antisera active in lymphocytotoxicity tests against nonHL‐A antigens are quite rare. The investigation utilized a sib‐pair method based on the consideration that sibs alike at the HL‐A locus should react alike, except for technical error, to sera detecting only HL‐A antigens and that most such alike sibs should frequently react differently to sera detecting nonHL‐A antigens. Details of the method are described and its sensitivity is illustrated by showing that several red cell antigens were readily detected as determined by loci independent of the HL‐A locus. © 1969 Blackwell Publishing Ltd