Efficacy of Recombinant S1 Protein Expressed in Pichia pastoris in Chicken & Using for Detection Titer Antibodies against Avian Infectious Bronchitis by ELISA

Infectious bronchitis (IB) is an acute, extremely contagious upper respiratory disease in chickens. The objective of this study was expressed and using of recombinant S1 Protein serotype 793/B expressed in pichia pastoris in order to serodiagnosis against avian infectious bronchitis antibody. The complete S1 gene (1623bp) was cloned in PTZ57 plasmid and transferred to E. coli (Escherichia coli)-XL1blue bacterium. Next cloned to pPICZB vectors and transferred to p. pastoris(Km71H). Produced protein were visualized by SDS (sodium dodecyl sulfate) PAGE gel that was about with 62KDa. Finally, the S1 recombinant protein was used to coat 96 well plate to recognize antibodies in sera against live Infectious bronchitis virus (IBV 4/91). As a result, this recombinant S1 protein Antigen can be used in an enzyme-linked immunosorbent assay (ELISA) for recognizing antibody titer against IBV. This recombinant protein was evaluated by Elisa, using a panel of field sera for known IBV titer That in the commercial kits, the optical gain of positive control is 0/741 ± 0/007 and the negative control is 0/167 ± 0/002, next the average Optical Density (OD) in the three farms were 2.585, 2.001, 1.657, resulting to the S/P ratio of was 4.212, 2.886, 2.484, respectively. The results of our effort for positive control and the negative control are 0/9 ± 0/010, 0/067 ± 0/008 respectively. The mean Optical Density of sera in 3 Flocks were showed 3.390, 2.737, 2.921, and the ratio of S/P 4. 01, 3.242 and 3.46. These results showed that our outcomes are neared to Biochek kit. The results also showed that recombinant protein S1 was able to identify different kinds of infectious bronchitis virus serotypes in poultry. It can be used for commercial ELISA kit.