Browsing by Author "Chellappa, Madhan Mohan"
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Item Newcastle Disease Virus Vectored Chicken Infectious Anaemia Vaccine Induces Robust Immune Response in Chickens(MDPI, 2021-10-02) Chellappa, Madhan Mohan; Dey, Sohini; Pathak, Dinesh Chandra; Singh, Asmita; Ramamurthy, Narayan; Ramakrishnan, Saravanan; Mariappan, Asok Kumar; Dhama, Kuldeep; Vakharia, VikramNewcastle disease virus (NDV) strain R2B, with an altered fusion protein cleavage site, was used as a viral vector to deliver the immunogenic genes VP2 and VP1 of chicken infectious anaemia virus (CIAV) to generate a bivalent vaccine candidate against these diseases in chickens. The immunogenic genes of CIAV were expressed as a single transcriptional unit from the NDV backbone and the two CIA viral proteins were obtained as separate entities using a self-cleaving foot-and-mouth disease virus 2A protease sequence between them. The recombinant virus (rR2B-FPCS-CAV) had similar growth kinetics as that of the parent recombinant virus (rR2B-FPCS) in vitro with similar pathogenicity characteristics. The bivalent vaccine candidate when given in specific pathogen-free chickens as primary and booster doses was able to elicit robust humoral and cell-mediated immune (CMI) responses obtained in a vaccination study that was conducted over a period of 15 weeks. In an NDV and CIAV ELISA trial, there was a significant difference in the titres of antibody between vaccinated and control groups which showed slight reduction in antibody titre by 56 days of age. Hence, a second booster was administered and the antibody titres were maintained until 84 days of age. Similar trends were noticed in CMI response carried out by lymphocyte transformation test, CD4+ and CD8+ response by flow cytometry analysis and response of real time PCR analysis of cytokine genes. Birds were challenged with virulent NDV and CIAV at 84 days and there was significant reduction in the NDV shed on the 2nd and 4th days post challenge in vaccinated birds as compared to unvaccinated controls. Haematological parameters comprising PCV, TLC, PLC and PHC were estimated in birds that were challenged with CIAV that indicated a significant reduction in the blood parameters of controls. Our findings support the development and assessment of a bivalent vaccine candidate against NDV and CIAV in chickens.Item Recombinant Newcastle Disease Virus (NDV) Expressing Sigma C Protein of Avian Reovirus (ARV) Protects against Both ARV and NDV in Chickens(MDPI, 2019-09-10) Saikia, Deep Prakash; Yadav, Kalpana; Pathak, Dinesh C.; Ramamurthy, Narayan; D’Silva, Ajai Lawrence; Marriappan, Asok Kumar; Ramakrishnan, Saravanan; Vakharia, Vikram N.; Chellappa, Madhan Mohan; Dey, SohiniNewcastle disease (ND) and avian reovirus (ARV) infections are a serious threat to the poultry industry, which causes heavy economic losses. The mesogenic NDV strain R2B is commonly used as a booster vaccine in many Asian countries to control the disease. In this seminal work, a recombinant NDV strain R2B expressing the sigma C (σC) gene of ARV (rNDV-R2B-σC) was generated by reverse genetics, characterized in vitro and tested as a bivalent vaccine candidate in chickens. The recombinant rNDV-R2B-σC virus was attenuated as compared to the parent rNDV-R2B virus as revealed by standard pathogenicity assays. The generated vaccine candidate, rNDV-R2B-σC, could induce both humoral and cell mediated immune responses in birds and gave complete protection against virulent NDV and ARV challenges. Post-challenge virus shedding analysis revealed a drastic reduction in NDV shed, as compared to unvaccinated birds