DNA sequence based typing of swine leukocyte antigens in Yucatan Miniature Pigs

Background: We have established a breeding program to develop additional lines of swine leukocyte antigens (SLA) homozygous miniature pigs derived from the Yucatan Miniature Pig. Yucatan pigs have been used extensively in biomedical research since the 1970s and are known for their docile nature and small size. The breed has no consanguinity with the Hormel or Pittman-Moore breeds used to produce the NIH Miniature Pigs, the only other SLA homozygous miniature pigs in the USA. Methods: SLA typing was initially done by restriction fragment length polymorphism. Then a cDNA library was constructed using spleen cells from these pigs, from which we cloned and sequenced nearly all alleles for the SLA- 1, 3, 2, 6, DRB1, DQA and DQB1 loci. Results: Four SLA homozygous lines were established with haplotypes that we have designated 'w, x, y and z'. An SLA class I/II crossover haplotype, designated 'q', with the SLA class I alleles of 'w' and the SLA class II alleles of 'z' was discovered and used to establish a fifth line. The cDNA sequences were used to develop locus specific primers for each locus and an reverse transcription-polymerase chain reaction sequence based typing (SBT) method. We have used this method to perform SBT on SLA homozygous Yucatan pigs with these haplotypes and on the NIH pig 'a, c and d' haplotypes. Conclusions: These pig lines represent a new resource for transplantation research and the methods we describe can be used to SLA type any herd of pigs.