Novel nucleotide variants in SLA-DOB and CD4 are associated with immune traits in pregnant sows.

Reinforcing the immunity of pregnant sows can not only improve their own health condition but also increase the survival rate and healthy status of their piglets. This study aims to find single-nucleotide polymorphism (SNP) and molecular markers that are associated with the immune traits of pregnant sows. SLA-DOB and CD4 were selected as candidate genes, and blood samples were randomly collected from pregnant Landrace sows and used to detect T-lymphocyte subsets, interferon alpha, interleukin 6, Toll-like receptor 3, serum antibody immunoglobulin G, and porcine reproductive and respiratory syndrome virus-specific antibody. Then, association analyses were conducted for the polymorphic sites of candidate genes with immune traits. We found 12 mutations in the two genes and conducted an association study with eight of them. Our results indicated that among the eight mutations, SNP1, SNP2, and SNP3 of the SLA-DOB gene and Ins9, SNP10, and SNP11 in the CD4 gene are newly discovered mutations. Except for SNP1, SNP3, and SNP11, the other five SNPs are associated with at least one immune trait tested. Especially, SNP2 and Ins9 are significantly associated with at least one of the T-lymphocyte subgroups and at least one antibody. These novel mutations have potential important effects on the polymorphic loci of the above immune traits in pregnant sows. The results suggest that the SLA-DOB and CD4 genes and their genetic mutations can be considered as important candidate genes and mutations for the immunity of pregnant sows.