Research Article
Maheswarappa G, Vijayarani
Abstract
Chicken are the most abundant birds in the world with a population of more than 24 billion. They are mainly kept for egg and meat production. Important economic lossess for the industry can occur, due to viral diseases such as Avian influenza and Newcastle disease. Vaccination is the only available tool to curb the outbreak of epidemics in poultry. Till today only few good vaccines are available to prevent the epidemic diseases. Recombinant DNA technology led to the development of recombinant vaccines and subunit vaccines but immunopotency of recombinant vaccines and subunit vaccines are not well understood in Newcastle disease vaccines. Hence, in this study, we cloned and expressed the fusion and haemagglutinin-neuraminidase genes of NDV in insect cells. Immunological study was carried out to assess the immunopotency of rec-F and rec-HN antigens in commercial broilers. Humoral and cell mediated immune response were evaluated. The immunogenic potentials of recombinant antigens along with commercial live and inactivated vaccine in stimulating humoral antibody response was recorded by haemagglutination inhibition (HI) test and ELISA. Cell mediated immune responses in stimulating the peripheral blood mononuclear cells by recombinant antigens were measured using tetrazolium dye (MTT assay). Expression of cytokines such as interferon alfa and interferon gamma, stimulated by recombinant F and HN antigens and commercial vaccines were studied by Real-time polymerase chain reaction. Our results revealed that recombinant antigens had similar immuneresponse as commercial incativated vaccines but less efficient in protecing the immunised birds than commercial live vaccine. Fusion protein has shown better protection than HN protein and combination of both antigens revealed more potency than individual antigen.