Dual infections with low virulent chicken infectious anaemia virus (lvCIAV) and intermediate infectious bursal disease virus (iIBDV) in young chicks increase lvCIAV in thymus and bursa while decreasing lymphocyte disorders induced by iIBDV.

The use of attenuated vaccines or the occurrence of low virulent T-lymphotropic or B-lymphotropic viruses in flocks may alter the immune responses of young chicks in spite of the absence of clinical signs. Infections with a low virulent T-lymphotropic chicken infectious anaemia virus (lvCIAV) followed by infection with an intermediate B-lymphotropic infectious bursal disease virus (iIBDV) were conducted in specific pathogen free chicks. Thirty-six 1-day-old chicks were infected with the lvCIAV strain (CAV-VAC®) and a similar number of chicks were inoculated with phosphate-buffered saline.

Chicken infectious anaemia vaccinal strain persists in the spleen and thymus of young chicks and induces thymic lymphoid cell disorders.

The chicken infectious anaemia virus (CIAV) infection may induce immunosuppression and persistent infection. The use of vaccination in young chicks is still controversial due to its low immune efficiency. In order to verify the viral persistency of a vaccinal strain of CIAV and its associated-lymphoid cell disorders, 54 1-day-old specific pathogen free chicks were vaccinated (CIAV-VAC(®); Intervet, Millsboro, Delaware, USA) and haematologic examination, expression of viral VP3 gene, humoral response and phenotyping of lymphoid cells were studied in lymphoid organs at various times post vaccination (p.

Prediction of optimal vaccination timing for infectious bursal disease based on chick weight.

Growth rate in broiler birds has increased substantially in the last decade due to improvement in genetics, feed formulation, cleaner environment, and vaccine formulations. As a result, it has become necessary to review and revise prediction method for vaccination in chicks. This study was undertaken to determine the possible use of the rate of weight gain rather than age in predicting vaccination time.

Characterization of monoclonal antibodies against avian reovirus strain S1133.

Monoclonal antibodies (MAbs) were produced against a vaccinal S1133 strain of avian reovirus. Characterization of six MAbs in Western blotting, radioimmunoprecipitation and gold immunoelectron microscopy revealed that the MAbs were specific to the outer capsid proteins, mu2/mu2c, sigma2 and sigma3. Two of three MAbs, directed against sigma2 protein, neutralized the virus infectivity in a broadly specific manner, whereas the third had no neutralizing activity.

Analysis of inter-serotypic structural relationships of infectious bursal disease virus using detergent solubilization and radioimmunoprecipitation with monoclonal antibodies.

Monoclonal antibodies (MAbs) neutralizing only the infectious bursal disease virus strains (IBDV) belonging to serotype 1 also immunoprecipitated the heterologous major antigenic proteins of serotype 2 IBDV. Detergent-solubilization followed by radioimmunoprecipitation assays (RIPA) using the MAbs revealed structural similarities between the conformation-dependent antigenic determinants of IBDV of the two existing serotypes. The presence of non-ionic detergent Triton X-100 determined the binding of altered proteins by MAbs in RIPA.