Anti-IBV Monoclonal antibody, Clone Dpw2D3

Infectious bronchitis virus (IBV) is a highly contagious viral disease of Family Coronaviridae. The current study reports the molecular and histopathological investigation of IBV strains emerged in outbreaks in the Nile Delta of Egypt. Tissue specimens from thirty-six chicken flocks were subjected to virus isolation, histopathology and PCR. Twenty-three isolates were confirmed as IBVs based on the amplification of the highly conserved nucleocapsid (N) gene. Further characterization of five selected isolates was done by amplification of the (S1) glycoprotein gene. Phylogenetic analysis revealed that the isolated strains were clustered into three distinct groups within the variant II Glade. Alignment of S lgene amino acid sequences showed significant amino acid substitutions in relation to the currently used vaccinal strains which displays that new IBV variants which are evolutionarily distant from vaccinal strains are still emerging within the Egyptian chicken flocks and are mostly associated with acute tubular nephrosis syndrome. (C) 2018 PVJ. All rights reserved

An investigation was undertaken of the extent of genetic variation occurring within infectious bronchitis virus (IBV) vaccine strains following vaccination of day-old broiler chicks. Chicks were divided into seven groups, with two groups receiving single Massachusetts (Mass) vaccinations while the other four were inoculated with combinations of different IBV serotypes; Mass, 793B, D274 and Arkansas (Ark). The remaining group was maintained as an unvaccinated control. Following vaccination, swabs and tissues collected at intervals were pooled and RNA was extracted for detection of IBV by reverse transcription polymerase chain reaction. Positive amplicons were sequenced for the part-S1 gene and compared to the original vaccine strain sequences. Single nucleotide polymorphisms, amino acid variations and hydrophobicity changes were identified and recorded for each sampling point. A total of 106 single nucleotide polymorphisms were detected within 28 isolates. The average single nucleotide polymorphism counts of swab isolates were greater than those found in tissue samples. This translated into 64 amino acid changes; however only six resulted in a change to the hydrophobicity properties. All hydrophobic alterations occurred within swab isolates and the majority were recovered at 3 days post vaccination suggesting such changes to be detrimental to early virus survival. Nucleotide deletions were seen only in the group given the combination of Mass and Ark. Of the 16 sequenced samples in this group, 13 contained the same AAT deletion at position 1033 1035 in the Ark strains. Findings presented in this study demonstrate alteration in the S1 nucleotide sequence following co-administration of live IBV vaccines.