Chicken major histocompatibility complex class I definition using antiserainduced by cloned class I sequences

Alloantisera directed against chicken class I MHC (BFIV) antigens were prod uced by using transfected cell lines expressing cloned BFIV sequences. The cloned BFIV sequences were from haplotypes *12, *13, and *21. Two laborator y-derived class I mutant sequences (BFIV13m126 and BFIV21m78) were develope d to analyze cross-reactive epitopes and to induce specific alloantisera. A ntisera were tested in hemagglutination and flow cytometry assays. The anti sera produced were highly specific and had minimal cross-reactivity. The an tisera induced by the BFIV21m78 mutant confirmed the significance of amino acids 78 and 81 in cross-reactivity between haplotypes B*21 and B*5. The hi ghly specific antisera were tested by hemagglutination on red blood cells o f 31 different MHC haplotypes. The consistency of hemagglutination patterns and minimal cross-reactivity demonstrated that these BFIV antisera are ext remely valuable in defining MHC haplotype in various chicken lines. Because of the extreme low level of recombination between the chicken class I and class Il loci, identification of BFIV allele can be used to define MHC hapl otype within a line. Complete identity between the transfected cell line an d the chicken used to produce the antiserum is required to ensure the monos pecificity.