Cluster of differentiation 4 gene (CD4) is well known for its role in immunity, but its effects on production traits remain to be elucidated. The present study was designed to explore single nucleotide polymorphisms (SNPs) in the exons, flanking introns, and promoter of CD4, as well as to analyze their effects on milk production traits (percentage of protein, fat, and lactose; mastitis indicator traits somatic cell count; and somatic cell score).
The effects of virus-like double-stranded RNA (dsRNA, PolyI:C) and DNA methyltransferase inhibitor (Aza-CdR) on CD4 gene expression were investigated in a porcine kidney cell line (PK15). We found that expression levels of TLR3 and IFNαwere significantly upregulated by PolyI:C, compared to the untreated PK15 cells, which shows that PolyI:C successfully mimics viral infection in PK15 cells.
Bovine mastitis is the most common and costly disease of dairy cattle. Cluster of differentiation 4 (CD4) is closely related to the immune response in mastitis. We quantified promoter CpG methylation levels of the CD4 gene in Chinese Holsteins with clinical mastitis (CM) and in healthy controls; these levels were quantitatively detected with bisulfite pyrosequencing assays and confirmed by cloning sequencing. We found that the bovine CD4 promoter had 16% more methyl groups in the cows with CM (75.0 ± 5.8%) compared to the controls (59.0 ± 8.5%).