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

Abstract

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.

Genetic association of sequence variation in exon 3 of the swine leukocyte antigen-DQA gene with piglet diarrhea in Large White, Landrace, and Duroc piglets

“…Exon 3 of SLA-DQA encodes the external cellular a2 domain, in which the a2 and b2 domains intertwine and form intra-chain disulfide bonds to maintain DQA molecular structure (Ho, 2006). In the present study, we confirmed that a statistical association exists between the genotypes of exon 3 and diarrhea susceptibility and resistance.…”

“…SLA-DQA is a SLA class II gene that is expressed at the mRNA and protein levels, is approximately 5.5 kb in length, and encodes a polypeptide of 255 amino acid residues (Ho, 2006). This gene contains four exons and three introns: exon 1 encodes a signal peptide, exons 2 and 3 encode corresponding external cellular a1 and a2 domains, and exon 4 encodes both the transmembrane and cytoplasmic domains.…”

Polymorphism and haplotype analyses of swine leukocyte antigen DQA exons 2, 3, 4, and their associations with piglet diarrhea in Chinese native pig

“…The SLA-DQA gene plays important roles in immune responsiveness and disease resistance (susceptibility) (Gautschi and Gaillard, 1990;Ho et al, 2010). Variation in genes may affect immune responses to pathogens, leading to variation in disease susceptibility (Racioppi et al, 1991).…”

SLA Homozygous Korean Native Pigs and Their Inbreeding Status Deduced from the Microsatellite Marker Analysis

“…The information of 47 primer pairs for SLA class I alleles (SLA-1, SLA-3, SLA-2), 47 primer pairs for SLA class II alleles (DRB1, DQB1, DQA) and positive control primers for the porcine α-actin (ACTA1 gene) was already obtained from description published by Ho et al (2009aHo et al ( , 2010a. The PCR amplification was carried out under the condition of denaturation for 10 min at 94 followed by 35 cycles of 96 for 15 s, 65 for 20 s and 72 for 20 s, with final extension of 3 min at 72 , then holding at 4 using a 96-well MJ Research PTC-200 thermal cycler (Bio-Rad, USA).…”

“…On the other hand, SLA class III genes having wide range of functions and some of them are related to the complement cascade (Naziruddin et al, 1998). In 2002, SLA Nomenclature Committee of the International Society for Animal Genetics (ISAG) has been established for the systematic nomenclature of the class I and class II SLA alleles (Smith et al, 2005a;Smith et al, 2005b;Ho et al, 2009a;Ho et al, 2009b;Ho et al, 2010a). The recent updates of SLA alleles can also be found in Immunopolymorphism Database-Major Histocompatibility Complex (IPD-MHC) website (http://www.ebi.ac.…”