Early immune responses to an adjuvant (AbISCO-100) tested in porcine peripheral blood mononuclear cell

Abstract: Immune stimulating complex (iscom) matrix is a formulation that is used as an adjuvant within research. The capability of the iscom matrix to elicit an immune response when not present together with an antigen has not been extensively investigated. One way to evaluate the status of the immune system is to measure the amount of cytokines that usually are produced by various cell types during an immune response. The aim of the present study was to evaluate the early immune responses in porcine peripheral blood mononuclear cells (PBMC) after stimulation in vitro with the iscom matrix, AbISCO®-100. The immune response was evaluated by measuring the mRNA expression for various cytokines, a chemokine receptor (CXCR4) and regulator of G-protein signaling (RGS16) in porcine PBMC after stimulation with AbISCO®-100 or other inducers like a lipopolysaccharide (LPS) and a CpG oligodeoxynucleotide (ODN 2216) used as controls. Quantitative real-time PCR analysis showed low increase (p ≤ 0.05) in mRNA expression of the pro-inflammatory cytokine TNF-α after 6 hours of stimulation with AbISCO®-100. This result indicates that AbISCO®-100 may have the capacity to evoke a cytokine response by itself. In addition, low but detectable increases in expression of IL-10, CXCR4 and RGS16 were observed in one of five pigs after stimulation with AbISCO®-100. In comparison, mRNA for IL-1β, IL-6, IL-10 (p ≤ 0.001), IL-12p40 and TNF-α (p ≤ 0.01) was induced after 6 hours exposure of the PBMC to LPS and for IFN-α (p ≤ 0.01) after 6 h in the presence of ODN 2216. Proliferation and viability test performed, demonstrated that AbISCO®-100 was not mitogenic and just had a small lytic effect on the PBMC . Thus, the iscom matrix, AbISCO®-100, does not appear to be toxic or induce any harmful early inflammatory responses in porcine PBMC. An extended period of incubation and use of a lager number of pigs are needed to better examine the effects of AbISCO®-100.