Inflammatory cytokines and antigen-responsive mononuclear cells in peripheral blood of cattle infected with Salmonella Takoradi

To determine the immunological response in lactating dairy cows infected wi th Salmonella (S.) Takoradi, the relationships among distributions of perip heral blood mononuclear cell (PBMC) subpopulations, endotoxin concentration s and dynamics of inflammatory cytokines in blood were investigated. The ra tio of CD4(+) T cells to CD8(+) T cells was significantly lower in the affe cted cattle than in the control cattle (p<0.05) to decrease in the number o f CD4(+) T cells in the infected cattle. In contrast, the numbers of <gamma >deltaT cells, MHC class II-positive cells were significantly higher in the affected cattle than in the control cattle (p<0.01 respectively). Endotoxe mia was found in all but one of the affected cattle. Serum IL-1 and IL-6 bi oactivities were significantly higher in the affected cattle than in the co ntrol cattle (IL-1, p<0.05; IL-6, p<0.01). Serum TNF-<alpha> activities and levels were not detected in the control and affected cattle. The activitie s of proinflammatory cytokines determined by the bioassay are important to the relationships between concentration of endotoxin, cytokines and clinica l signs, such as leukocytosis, leukopenia, fever or bacterial shedding. Ser um IL-2 levels were lower in the affected cattle than in the control cattle . Serum IFN-gamma was not detected in the affected cattle except one. These results by the ELISA seemed to reflect the condition of subpopulation in t he PBMCs from the shedding cattle. The present results suggest that cellula r immunity is suppressed while the humoral immunity is activated in acute b ovine salmonellosis.