Infectious bronchitis (IB), caused by infectious bronchitis virus (IBV), is a highly contagious chicken disease, and can lead to serious economic losses in poultry enterprises. The continual introduction of new IBV serotypes requires alternative strategies for the production of timely and safe vaccines against the emergence of variants. Modification of the IBV genome using reverse genetics is one way to generate recombinant IBVs as the candidates of new IBV vaccines. In this study, the recombinant IBV is developed by replacing the ectodomain region of the S1 gene of the IBV Beaudette strain with the corresponding fragment from H120 strain, designated as rBeau-H120(S1e). In Vero cells, the virus proliferates as its parental virus and can cause syncytium formation. The peak titer would reach 10(5.9) 50% (median) tissue culture infective dose/mL at 24 h post-infection. After inoculation of chickens with the recombinant virus, it demonstrated that rBeau-H120(S1e) remained nonpathogenic and was restricted in its replication in vivo. Protection studies showed that vaccination with rBeau-H120 (S1e) at 7-day after hatch provided 80% rate of immune protection against challenge with 10(3) 50% embryos infection dose of the virulent IBV M41 strain. These results indicate that rBeau-H120 (S1e) has the potential to be an alternative vaccine against IBV based on excellent propagation property and immunogenicity. This finding might help in providing further information that replacement of the ectodomain fragment of the IBV Beaudette S1 gene with that from a present field strain is promising for IBV vaccine development.

Aims: To investigate the role of herpes virus entry mediator (HVEM) in viral entry and inflammatory cytokine production in response to herpes simplex virus (HSV) type 1 challenge in human corneal epithelial cells. Methods: HVEM expression in human corneal epithelial cells was determined by immunofluorescence and flow cytometry. The HSV-1 virus expressing β-galactosidase was used to challenge corneal epithelial cells and viral entry assays were performed to ascertain HSV-1 entry into cells. Levels of cytokines TNF-α, IL-6, IFN-γ, IL-12, and IL-18 and chemokines MIP-1α, MIP-1β and MIP-2 were detected in corneal epithelial cells treated with control or HVEM siRNA in response to HSV-1 challenge. Results: Human corneal epithelial cells were positive for HVEM expression and showed high susceptibility to HSV-1 entry. Silencing of HVEM did not alter viral entry dramatically. However, levels of the cytokine IFN-γ and chemokines MIP-1α and MIP-1β were measured to be higher in HVEM siRNA-treated cells than control after HSV-1 challenge. Conclusions: HVEM in human corneal epithelial cells may act to dampen the production of some cytokines and chemokines and thus it may modulate the innate immune response against HSV-1. This may provide a novel mechanism for the pathogenesis of HSV-1 infection in the cornea.