Lipopolysaccharide Stimulation of Peripheral Blood Mononuclear Cells of Indigenous Pigs Causes Enhanced Expression of Pro-inflammatory Cytokines Over Exotic Pigs

Abstract

Background: Selective breeding in pigs based on a higher potential of disease resistance can be achieved by studying the association between immune responsiveness and susceptibility to infectious diseases. The early immune responsiveness of pigs assessed in a quantifiable scale for different determinant cytokine genes’ expression involved in regulation of immune response can be a major determinant for evaluating the immune responsiveness. Methods: In this study, we carried out the quantitative relative expression of candidate cytokine genes [Interleukin-1 beta-(IL1b), IL6, IL10 and tumor necrosis factor-alpha (TNFa) and toll-like receptor-4 (TLR4) gene expression in the lipopolysaccharide (LPS) stimulated peripheral blood mononuclear cells (PBMCs) of Zovawk (indigenous) and Large White Yorkshire (LWY-exotic) pig breeds using real-time PCR to understand the differences in swift immune responsiveness against gram-negative bacteria. Results: Zovawk PBMCs’ pro-inflammatory cytokines IL1b and IL6 expression increased rapidly with LPS stimulation up to 12 h, being significantly higher as early as 4 h compared to that of the LWY PBMCs. In Zovawk pigs, the pro-inflammatory cytokine genes’ expression was found to be quick and high; whereas, in LWY pigs the response was slow and low. Interestingly, the expression of IL10 was not detected in LPS-stimulated PBMCs of Zovawk pigs indicating that the remarkably higher expressions of IL6 and IL1b in response to LPS are within the threshold of the Zovawk pigs which have evolved through generations. Our findings clearly indicate the sturdy and early immune responsiveness of indigenous pigs against gram-negative bacteria over the exotic pigs.