Temporal changes in the expression of avian ß-defensins in the chicken vagina during sexual maturation and Salmonella infection.

ABSTRACT

Avian ß-defensins (AvßDs) constitute a family of antimicrobial peptides that are critical to innate immunity in chickens, providing protection against microbial pathogens including Salmonella Enteritidis (SE). As apart from the digestive tract another main route of SE colonization in birds is via infection of the oviduct and specifically of the vagina, the aim of this study was to investigate the expression of the complete family of AvßDs, in the chicken vagina in vivo, to determine whether sexual maturation affects their mRNA abundance and to investigate whether SE infection alters the vaginal AvßDs expression. Expression analysis revealed that 11 members of the AvßD family were expressed in the chicken vagina. Quantitative real-time PCR analysis revealed that the mRNA abundance of five AvßDs was up regulated and of one AvßD was down regulated with respect to sexual maturation. In addition SE infection resulted in a significant induction of AvßD5, 7, 10, 11, 12 and 14 in the vagina of sexually mature birds, and in a significant induction of AvßD5 and 11 in the vagina of aged birds. These findings provide strong evidence to suggest that an AvßD-mediated immune response mechanism exists in the chicken vagina providing protection against bacterial pathogens including Salmonella species.