| Swine leukocyte antigen polymorphism has been associated with immunologic responses, pig production traits, and has important implications for swine animal models. Studies of SLA polymorphism have been hampered by the limitations of current serologic and cellular based SLA typing techniques. An ideal method would be accurate, inexpensive, rapid and capable of typing large numbers of pigs. Two DNA based methods for SLA typing were developed and tested using three experimental herds of miniature pigs. One method is based on cloning and sequencing alleles from each locus (SBT) and the other is a PCR based method using site specific primers (PCR-ssp). The SBT method was used to characterize the founders of a crossbred herd of Sinclair melanoma and Hanford pigs by sequencing PCR products amplified with SLA-DQβ1, DRβ1, -2, -3 and -1 locus specific primers. Site specific PCR primers were designed to amplify the alleles identified in the herd founders. PCR-ssp assay conditions were first optimized using samples from two other herds of miniature swine, Yucatan and NTH, which have well characterized SLA haplotypes. Thirty-six Yucatan samples were successfully typed with the Yucatan Miniature Swine PCR-ssp assay and twenty-seven NIH samples were successfully typed with the NIH Miniature Swine PCR-ssp assay. Using these optimized PCR-ssp assay conditions; SLA haplotypes were identified in the Sinclair and Hanford herd founders. Only two haplotypes could not be separated. A total of one hundred and forty-four samples from the crossbred herd were SLA typed. SLA typing data from this herd will be used to study a previously reported correlation between SLA type and development of melanoma. Hopefully this data will aid in the development of a nomenclature system for SLA alleles. Towards this goal, all available SLA sequence data was analyzed using a combination of phylogeny and visual inspection of multiple sequence alignment for share polymorphic sequence motifs. The identified groups may form the basis of a nomenclature system and a PCR-ssp assay designed to detect them. |
