1Department of Microbiology, Acharya N.G. Ranga Agricultural University, Tirupati - 517502, (Andhra Pradesh), INDIA.
2Department of Veterinary Microbiology, College of Veterinary and Animal Sciences, G.B. Pant University of Agriculture and Technology, pantnagar-263145, (Uttaranchal), INDIA.
*E-mail: raovdp@rediffmail.com
A competitive enzyme linked immunosorbent assay (c-ELISA) has been standardized for seromonitoring the vaccine response to haemorrhagic septicaemia (H.S.). Two different antigens, capsular and OMP antigens were tested to determine their suitability for plate coating in ELISA. Hyperimmune serum against whole cell antigen of Pasteurella multocida P52 strain was used as competing antibody in the standaridization of c-ELISA. Goat anti rabbit IgG HRPO conjugate served as immunoconjugate. The cut off value (50 per cent of inhibition) was determined using a set of negative sera collected from young animals, which had never been vaccinated or infected with H.S. Sera from animals collected after immunization with H.S. alum precipitated vaccine were used as positive controls. In the present study, c-ELISA was standardized to assess the protective immunity using known passive mouse protection test (PMPT) positive and PMPT negative sera. Examination of sera of cattle, sheep, goat and pigs by c-ELISA demonstrated antibodies in 268 (68.7%) and 255 (65.3%) out of a total 390 samples using capsular and outer membrane (OMP) antigens, respectively. The mean of ELISA in the post-vaccination sera were significantly higher (P<0.001) when compared to prevaccinated sera. Competitive-ELISA has advantage over other ELISA for monitoring the immune response to vaccination in all species of animals with single antispecies antibody conjugate, as H.S. is known to affect wide range of animal hosts.
Haemorrhagic septicaemia, Pasteurella multocida P52, seromonitoring, c-ELISA
