Molecular characterization of swine leucocyte antigen class II genes in outbred pig populations.

The highly polymorphic swine leucocyte antigen (SLA) genes are among the most important determinants of swine immune responses to disease and vaccines. Accurate and effective SLA genotyping methods are required to understand how SLA gene polymorphisms affect immunity, especially in outbred pigs with diverse genetic backgrounds. In this study, we present a simple and rapid molecular-based typing system for characterizing SLA class II alleles of the DRB1, DQB1 and DQA loci. This system utilizes a set of 47 sequence-specific PCR primers developed to differentiate alleles by groups that share similar sequence motifs. We applied this typing method to investigate the SLA class II diversity in four populations of outbred pigs (n = 206) and characterized a total of 19 SLA class II haplotypes, six of which were shared by at least three of the sampled pig populations. We found that Lr-0.1 (DRB1*01XX-DQB1*01XX-DQA*01XX) was the most prevalent haplotype with a combined frequency of 16.0%, followed by Lr-0.2 (DRB1*02XX-DQB1*02XX-DQA*02XX) with 14.6% and Lr-0.15b (DRB1*04XX-DQB1*0202-DQA*02XX) with 14.1%. Over 70% of the pigs (n = 147) had at least one copy of one of these three haplotypes. The PCR-based typing system described in this study demonstrates a reliable and unambiguous detection method for SLA class II alleles. It will be a valuable tool for studying the influence of SLA diversity on various immunological, pathological and physiological traits in outbred pigs.

Sequence-based characterization of swine leucocyte antigen alleles in commercially available porcine cell lines.

A total of 53 alleles at five highly polymorphic swine leucocyte antigen (SLA) loci (SLA-1, SLA-3, SLA-2, SLA-DRB1, and SLA-DQB1) were identified in eight commercially available porcine cell lines (ESK-4, LLC-PK1, MPK, PK13, PK15, PT-K75, SK-RST, and ST). This information is essential for the use of these cell lines to understand the role of SLA genes and proteins in swine models of transplantation, xenotransplantation, and in swine immune responses to infectious diseases and vaccines. The ready availability of these cell lines also makes them a good source of reference DNA for SLA allele typing.

Molecular characterization of swine leucocyte antigen class I genes in outbred pig populations.

The highly polymorphic swine leucocyte antigen (SLA) genes are one of the most important determinants in swine immune responses to infectious diseases, vaccines, and in transplantation success. Study of SLA influence requires accurate and effective typing methods. We developed a simple and rapid method to type alleles at the three classical SLA class I loci (SLA-1, SLA-3 and SLA-2) using the PCR-sequence-specific primer (PCR-SSP) strategy. This typing system relies on 47 discriminatory PCR primer pairs designed to amplify the SLA class I alleles by groups that have similar sequence motifs. We applied this low-resolution group-specific typing method to characterize the SLA class I alleles present in three outbred pig populations (n = 202). Alleles from 24 class I allele groups corresponding to 56 class I genotypes were detected. We also identified 23 low-resolution SLA class I haplotypes in these pigs and found haplotypes Lr-1.0 (SLA-1*01XX-SLA-3*01XX-SLA-2*01XX) and Lr-4.0 (SLA-1*04XX-SLA-3*04XX-SLA-2*04XX) in all three pig populations with a high prevalence. Over 80% of the pigs examined (n = 162) were found to bear at least one of these haplotypes, resulting in a combined haplotype frequency of nearly 50%. This PCR-SSP-based typing system demonstrates a reliable and unambiguous detection of SLA class I alleles, and can be used to effectively investigate the SLA diversity in outbred pig populations. It will help to identify the role of SLA antigens in disease-resistant pigs and may facilitate the development of effective vaccines.