Salmonella infection increases porcine antibacterial peptide concentrations in serum.

PR-39 is a multifunctional neutrophil peptide involved in host defense and inflammation. To investigate the involvement of PR-39 in a Salmonella choleraesuis infection, a PR-39 enzyme immunoassay was developed. The concentrations of PR-39 in serum were 13.6 +/- 1.9 ng/ml before challenge and increased (P < 0.01) threefold by 10 to 14 days postinfection. Peripheral blood neutrophil counts paralleled the changes in the concentrations of PR-39 in serum, both returned to basal values by 4 weeks postinfection. These findings suggest that the concentrations of serum PR-39 reflect the involvement of this antibacterial peptide in the host's response to an S. choleraesuis infection.