The aims of this study were to (i) determine the types of avian beta-defensin genes (AvbetaD) expressed in the hen oviduct and (ii) to examine the effects of lipopolysaccharide (LPS) treatment in vivo on their expression in the vagina. Birds were i.v. treated with LPS (1 mg/kg of BW), and subsequently the oviducts were analyzed 0, 3, 6, 12, or 24 h after LPS administration. The mRNA expression for AvbetaD was examined by reverse transcription-PCR using RNA preparations from the mucosal tissues of all the oviductal segments. Furthermore, changes in their mRNA expression profiles in the vagina were analyzed by semiquantitative reverse transcription-PCR. The AvbetaD-1, -2, -3, -4, -5, -7, -8, -9, -10, -11, and -12 were identified in each oviductal segment from infundibulum to vagina. Among these AvbetaD, the expression of AvbetaD-3, -5, -10, -11, and -12 in the vagina were significantly increased in response to LPS treatment, whereas the others did not show significant changes. These results suggest that all 11 types of AvbetaD are expressed in the hen oviduct and at least 5 of them in the vagina show increased expression in response to LPS.

Immune function in the vagina of hen oviduct is essential to prevent infection by microorganisms colonizing in the cloaca. The aim of this study was to determine whether CpG oligodeoxynucleotides (CpG-ODN) stimulate the expression of avian b-defensins (AvBDs) in hen vaginal cells. Specific questions were whether CpG-ODN affects the expression of AvBDs and proinflammatory cytokines and whether the cytokines affect AvBDs expression in vaginal cells. The dispersed vaginal cells of White Leghorn laying hens were cultured and stimulated by different doses of lipopolysaccharide (LPS), CpG-ODN, interleukin 1b (IL1B), or IL6. The cultured cell population contained epithelial cells, fibroblast-like cells, and CD45-positive leukocytes. The immunoreactive AvBD3, -10, and -12 were localized in the mucosal epithelium in the section of the vagina. The expression of AvBDs, IL1B, and IL6 was analyzed by quantitative RT-PCR. RT-PCR analysis showed the expression of AvBD1, -3, -4, -5, -10, and -12 in the cultured vaginal cells without stimulation. Toll-like receptors (TLRs) 4 and 21, which recognize LPS and CpG-ODN respectively and IL1 and IL6 receptors (IL1R1 and IL6R) were also expressed in them. The expression of IL1B, IL6, and AvBD10 and -12 was upregulated by LPS, whereas only IL1B and IL6 were upregulated by CpG-ODN. IL1B stimulation upregulated AvBD1 and -3 expression, whereas IL6 stimulation did not cause changes in AvBDs expression. These results suggest that CpG-ODN derived from microbes upregulates the expression of IL1B and IL6 by interaction with TLR21 and then IL1B induces AvBD1 and -3 to prevent infection in the vagina.

No abstract