Heterologous Live IBV Vaccination in Day-Old Commercial Broiler Chicks: clinical Signs, Ciliary Health, Immune Responses and Protection Against Variant IBVS.

Heterologous Live IBV Vaccination in Day-Old Commercial Broiler Chicks: clinical Signs, Ciliary Health, Immune Responses and Protection Against Variant IBVS.
Avian Pathol. 2016 Jan 8;:1-29
Authors: Awad F, Hutton S, Forrester A, Baylis M, Ganapathy K
Abstract
Groups of one-day-old broiler chicks were vaccinated via oculo-nasal route with different live infectious bronchitis virus (IBV) vaccines; Massachusetts (Mass), 793B, D274, or Arkansas (Ark). Clinical signs and gross lesions were evaluated. Five chicks from each group were humanely killed at intervals and their trachea collected for ciliary activity assessment and for the detection of CD4+, CD8+ and IgA-bearing B cells by immunohistochemistry (IHC). Blood samples were collected at intervals for the detection of anti-IBV antibodies. At 21 days post vaccination (dpv), protection conferred by different vaccination regimes against virulent M41, QX and 793B was assessed. All vaccination programmes were able to induce high levels of CD4+, CD8+ and IgA-bearing B cells in the trachea. Significantly higher levels of CD4+ and CD8+ expression were observed in the Mass2+793B2-vaccinated group compared to the other groups. Protection studies showed that the group of chicks vaccinated with Mass2 +793B2 produced 92% ciliary protection against QX challenge; compared to 53%, 68% and 73% ciliary protection against the same challenge virus by Mass1+D274, Mass1+793B1 and Mass3+Ark respectively. All...

Source: Avian Pathology - January 8, 2016 Category: Pathology Authors: Awad F, Hutton S, Forrester A, Baylis M, Ganapathy K Tags: Avian Pathol Source Type: research