Quantity of HI antibodies in sera of SPF chickens inoculated with inactivated commercial pigeon paramyxovirus, type1 vaccine in comparison with vaccinated pigeon

الملخص EN

The correlation between quantities of pigeon paramyxovirus type 1 (PPMV- 1)-haemagglutination inhibition (HI) antibodies exhibited by sera of specific pathogen free (SPF) chicks and susceptible pigeon squabs at 7, 14, 21 and 28 days after inoculation with one and two pigeon doses of three batches of commercial inactivated PPMV-1vaccine was assessed throughout the present study to declare the reasonability of using SPF-chicken for evaluating the immunogenicity of inactivated PPMV-1 vaccine instead of pigeon in case of difficulty to find susceptible pigeon squabs in the market.

three groups of each susceptible pigeon squabs and spf-chicks were used for immunogenicity assay of each batch of the tested vaccine.

blood samples were collected weekly from ten individuals of each inoculated and control group, and PPMV-1 HI antibodies were measured in each individual serum sample by HI test using PPMV-1HA antigen containing 4 HA units, and geometric mean titer of each group was calculated.

SPF-chickens were reacted serologically with the test vaccine batches; PPMV-1-HI antibody GMTs of range 6.0 log2 – 7.1 log2 and mean 6.4 log2, and 6.0 log2 – 7.4 log2 and 6.6 log2 were determined in sera of chickens by the third and fourth weeks after inoculation with the pigeon dose respectively, while PPMV-1-HI antibody GMTs of range 7.0 log2 – 8.8 log2 and mean 7.6 log2, and 7.1 log2 - 8.9 log2 and mean 7.8 log2 and 8.1 log2 - 9.5 log2 and mean 8.8 log2 were determined in sera of pigeons by the third and fourth weeks after inoculation respectively.

the obtained Relative Potencies of the test vaccine batches in chickens were ranged between 0.84 and 0.86, and the minimum required PPMV-1-HI antibody GMT in sera of SPF-chicks collected between the third and fourth weeks after inoculation with the pigeon dose should be equal or more than 6.0 log2 X 85/ 100 = 5.1 log2.

in-conclusion, the present study data suggest that SPF-chickens represent the reasonable alternative host for immunogenicity assay with one recommended dose of pigeon by inactivated PPMV-1 vaccine instead of susceptible pigeon.