Improvement of immunodiagnosis of avian infectious bronchitis virus (IBV) infection by the detection of IgM and IgG antibodies using a new recombinant nucleoprotein-based Elisa.

Projeto/Plano de Ação: 05.11.11.002

Avian infectious bronchitis vírus (IBV): effect of vaccine doses on mucosal imune responses and protection after challenge in chickens.

Projeto/Plano de Ação: 05.11.11.002

Immune-protection mechanisms against late challenge with avian infectious bronchitis vírus (IBV) induced by a single-dose of an attenuated vaccine in day-old chicks.

Projeto/Plano de Ação: 05.11.11.00

Development of a microplate immunocapture (IC) RT-PCR assays for the detection of avian influenza virus (AIV) and infectious bronchitis virus (IBV).

Projeto/Plano de Ação: 11.11.11.111

Cloned nucleoprotein (NP) gene of avian influenza virus for using as a positive control in syber green I real time RT-PCR (RRT-PCR).

Projeto/Plano de Ação: 11.11.11.111

Comparative evaluation of immune responses and protection of chitosan nanoparticles and oil-emulsion adjuvants in avian coronavirus inactivated vaccines in chickens.

Efficient vaccines are the main strategy to control the avian coronavirus (AvCoV), although several drawbacks related to traditional attenuated and inactivated vaccines have been reported. These counterpoints highlight the importance of developing new alternative vaccines against AvCoV, especially those able to induce long-lasting immune responses. This study evaluated and compared two inactivated vaccines formulated with AvCoV BR-I variants, one composed of chitosan nanoparticles (AvCoV-CS) and the second by Montanide oily adjuvant (AvCoV-O). Both developed vaccines were administered in a single dose or associated with the traditional Mass attenuated vaccine. The AvCoV-CS vaccine administered alone or associated with the Mass vaccine was able to induce strong humoral and cell-mediated immune (CMI) responses and complete protection against IBV virulent infection, wherein single administration was characterized by high IgA antibody levels in the mucosa, whereas when associated with the Mass vaccine, the serum IgG antibody was predominantly observed. On the other hand, single administration of the oily vaccine presented poor humoral and CMI responses and consequently incomplete protection against virulent challenge, but when associated with the Mass vaccine, immune responses were developed, and complete protection against infection was observed. Both of our experimental vaccines were able to induce full protection against virulent IBV challenge. A single dose of AvCoV-CS vaccine was sufficient to achieve complete protection, while AvCoV-O required a previous priming by a Mass strain to complete the protection

Early immune responses and development of pathogenesis of avian infectious bronchitis viruses with different virulence profiles.

Avian infectious bronchitis virus (IBV) primarily replicates in epithelial cells of the upper respiratory tract of chickens, inducing both morphological and immune modulatory changes. However, the association between the local immune responses induced by IBV and the mechanisms of pathogenesis has not yet been completely elucidated. This study compared the expression profile of genes related to immune responses in tracheal samples after challenge with two Brazilian field isolates (A and B) of IBV from the same genotype, associating these responses with viral replication and with pathological changes in trachea and kidney. We detected a suppressive effect on the early activation of TLR7 pathway, followed by lower expression levels of inflammatory related genes induced by challenge with the IBV B isolate when compared to the challenge with to the IBV A isolate. Cell-mediated immune (CMI) related genes presented also lower levels of expression in tracheal samples from birds challenged with B isolate at 1dpi. Increased viral load and a higher percentage of birds with relevant lesions were observed in both tracheal and renal samples from chickens exposed to challenge with IBV B isolate. This differential pattern of early immune responses developed after challenge with IBV B isolate, related to the downregulation of TLR7, leading to insufficient pro-inflammatory response and lower CMI responses, seem to have an association with a most severe renal lesion and an enhanced capability of replication of this isolate in chicken

Diferentes respostas imunes locais induzidas após desafio com isolados de campo brasileiros do vírus da bronquite infecciosa das galinhas.

A Bronquite Infecciosa das galinhas (BI), causada pelo vírus da BI (VBI), possui ocorrência mundial e é responsável por perdas de milhões de dólares anuais na produção de frangos, matrizes e postura. A replicação primária do VBI ocorre no epitélio traqueal, ocasionando uma série de alterações patológicas. Entretanto, os mecanismos envolvidos localmente na resposta imune e patogênese da BI permanecem não elucidados completamente. O objetivo desse trabalho foi o de avaliar comparativamente o perfil de expressão de genes envolvidos na resposta imune na traqueia de aves infectadas experimentalmente com isolados de campo brasileiros do VBI genotipados como ?variantes?