Submitted to: Safepork
Publication Type: Proceedings
Publication Acceptance Date: June 1, 2005
Publication Date: September 6, 2005
Citation: Genovese, K.J., He, H., Lowry, V., Kogut, M.H. 2005. Effect of CpG on swine neutrophils and use against Salmonella in pigs. Proceedings of SafePork 2005. p. 271-273. Interpretive Summary: New intervention strategies for the control of Salmonella and other food-borne pathogens in domestic swine need to be developed to reduce producer dependence on antibiotics. In this manuscript we describe the use of a synthetic piece of bacterial DNA called CpG to control Salmonella in weaned pigs. Pigs treated with CpG had reductions in fecal shedding of Salmonella and had reduced levels of Salmonella in the gut and internal organs. In addition, laboratory studies revealed that CpG was most likely causing reductions in Salmonella in pigs by activating cells of the pig’s immune system which kill the Salmonella bacteria.
Technical Abstract: Neutrophil oxidative burst/degranulation activities were measured using CpG in vitro stimulation. Neutrophils isolated from pigs 6 weeks of age were incubated with treatment for 1 hr at 39C. Neutrophils had increased degranulation activity when treated with CpG when compared to the activity of cells treated with non CpG. Neutrophils treated with CpG exhibited an increase in oxidative burst. CpG resulted in levels of activity comparable to those observed with PMA stimulation. Two of the swine CpG (p2006 and pD19) were chosen for administration to swine to observe the effects on S. choleraesuis (SC) infection. Pigs were administered 1 mg of CpG and subsequently challenged with SC. SC numbers in cecal contents in one CpG group were reduced by two to three logs when compared to control numbers and other CpG groups. In addition, reductions in SC positive rectal swabs, liver, spleen, jejunal, ileal, and colon colonization were observed.