Skip Navigation Links

» Veterinary Biotechnology Division

Recombinant DNA Lab

Dr Meena Kataria, Head, Division of Biochemistry

Immunofluorescence analysis of VP2 protein expression in rNDV-F/VP2 virus. Confluent monolayers of Vero cells were infected with recombinant viruses rNDV-F/VP2 and rNDV-F at a multiplicity of infection (MOI) of 0.01. The cells were examined by immunofluorescence assay (IFA) with IBDV specific mAb against the VP2 protein and an NDV-specific polyclonal antibody followed by a mixture of the FITC labeled sheep anti-mouse IgG (B,F) and Alexa Fluor 568-labeled goat anti-chicken IgG (C,G).

Recombinant DNA Lab pursues research activities related to development of new generation diagnostics and vaccines against important poultry viral diseases. The immunogenic genes of the viral diseases are being expressed in bacterial, yeast and mammalian expression systems depending on the need. Some of the genes that have been expressed include haemagglutinin and nucleoprotein genes of Newcastle disease virus (NDV), VP2 gene of infectious bursal disease virus (IBDV), nucleoprotein gene, S1 genes of infectious bronchitis virus, UL30, glycoprotein D genes of duck enteritis virus, sigma C, B genes of avian reo virus and fiber gene of hydropericardium syndrome virus. Work related to usage of Toll like receptors as molecular adjuvants is also actively being pursued in the laboratory.

The expression of VP2 gene of infectious bursal disease in Saccharomyces cerevisiae resulted in the generation of sub viral particles (SVPs) which were subsequently used to develop a single serum dilution ELISA kit and a recombinant vaccine. The vaccine induces protective immunity in specific pathogen free chicks against very virulent IBDV challenge. The generated SVPs, in addition to their ability to stimulate antibody response, are highly effective in stimulating antigen specific lymphocyte proliferative and cytotoxic T lymphocyte responses. The vaccine does not cause immunosuppression as has been demonstrated by an intact histological architecture of the bursa of Fabricius. The vaccine protects the broiler birds in presence of maternally derived antibodies (MDA) and can safely be administered to day-old chicks. A patent has been granted for the development of recombinant antigen based rapid sero diagnosis of IBD. The nucleoprotein of NDV expressed from yeast was used in the development of a single serum dilution ELISA kit for serological profiling of ND.

Development of new generation vaccines against important poultry viral diseases is being actively pursued using reverse genetics technology. The mesogenic NDV strain ‘R2B’ with green fluorescent protein reporter gene and a lentogenic strain ‘F’ with VP2 gene of IBDV have been successfully rescued in the laboratory. Further, the R2B fusion protein cleavage site has been modified to carry an avirulent amino acid motif and the viral rescue has been carried out. It is envisaged to use NDV as a viral vector to deliver immunogenic genes of some of the important viral diseases of poultry and livestock.

© 2014 reserved with IVRI