The pig histocompatibility system SLA: serological study on a group of antigenic specificities

The report presents an analysis of a group of class I SLA reagents which were highly correlated within one cluster in a previous analysis. Further population and family studies, and selected purification of several of these reagents led to the identification of 4 distinct specificities, namely SLA A 15, B 18, C 1 and A 16. Three of them, SLA A 15, B 18 and C 1, are actually in strong linkage disequilibrium and represent the main SLA haplotype in the Large White breed. SLA A 16 is present essentially in the Landrace breeds. SLA A 16 displays a strong cross-reaction with SLA A 15 and there is another specificity in linkage disequilibrium with SLA A 16 which cross-reacts with SLA B 18. Altogether, the strong linkage disequilibrium and the high degree of cross-reactivity among the allelic products of the SLA complex explain the failure to detect the diversity of our reagents in previous studies.