Efficacy of Mucosal adjuvants on induction of systemic immune responses to newcastle disease vaccine strain

Intranasal immunization of broiler chicks with lentogenic ‘F’ strain of Newcastle disease incorporating or lacking mucosal adjuvants viz., Cholera toxin B subunit (CTB), heat labile enterotoxin of Escherichia coli (LT) and a lipoidal amine adjuvant, averidine (Avr) was carried out. Haemagglutination inhibition (HI) tests and indirect ELISA were done to assess the antiviral serum antibody levels up to 6 weeks post vaccination. Relatively higher levels of antiviral serum antibodies were observed in birds vaccinated with CTB adjuvanted vaccine. The early peaking of antibody levels was also observed in CTB adjuvanted group. Higher in-vitro proliferation of peripheral blood lymphocytes to viral antigen was observed in LT adjuvanted vaccine group. These results suggest differential adjuvanting ability of bacterial toxins when co-administered with live attenuated Newcastle disease vaccines.