DNAA TYPING FOR BOLA CLASS-I USING SEQUENCE-SPECIFIC PRIMERS (PCR-SSP)

The analysis of cattle MHC (BoLA) class I gene expression is an essent ial component of studies on immune responses and susceptibility to dis ease. International BoLA workshops have generated data and reagents th at allow discrimination of class I molecules at the haplotype level, b ut progress has been limited by difficulties encountered in defining s ingle alleles. Our aim in this study was to develop a DNA-based system for improved identification of expressed class I alleles, utilizing a vailable cDNA sequences derived from cattle carrying a series of serol ogically defined class I specificities. This method has allowed more a ccurate typing of animals for expression of the class I genes present within a small number of haplotypes. The method has also reliably diff erentiated between allelic variants (identified by prior sequence anal ysis) and has split existing serological specificities. The data show that MHC class I genes in cattle are more polymorphic than demonstrate d by serology and biochemical analysis.