Establishment and Application of Sandwich ELISA Method for Detecting Avian Beta-defensin 6

To detect avian beta-defensin 6(AvBD6) quantitatively,a sandwich ELISA method was established and applied to detect the concentration of AvBD6 in serum. The results showed that the optimal dilution of capture antibody( mouse anti-B cell linear epitopes of AvBD6 polyclonal antibody),detecting antibody( rabbit anti-Nterminal of AvBD6 polyclonal antibody) and horseradish peroxidase( HRP)-conjugated goat anti-rabbit IgG was2 500,2 000 and 10 000,respectively. The standard curve regression equation was y = 12 024x- 2 583,(R2= 0. 9842) in the linear detection range from 20 to 320 ng /mL. The serum AvBD6 concentration of control group was slightly higher than that of ACTH group( P 0. 05) after 1 day of ACTH( 25 IU /kg BW) injection,but the AvBD6 concentration of the control group was slightly lower than that of ACTH group(P 0. 05) after 5 d of ACTH injection;and the effect was not significant. The serum AvBD6 concentration of infected group after 24 h of Escherichia coli exposure or 3 h and 24 h of salmonella exposure were significantly higher than that of the control group(P 0. 05).Our results indicated that AvBD6 involved in the resistance to system infection of Escherichia coli and salmonella.