Standardization of Quality Control Protocol for Evaluation of Recombinant HVT-H5 Vaccine
Standardization of Quality Control Protocol for Evaluation of Recombinant HVT-H5 Vaccine
Ola Youssef 1; EL-Deeb A.H.2 Nassif S.A.1 and Ahmed A. El-Sanousi 2.
ABSTRACT
Background: There is no international quality control protocol for evaluation of recombinant H5
vaccines had been established yet so, these vaccines are evaluated by applying the conventional QC
tests such as identity, safety, purity, potency and efficacy that were not satisfactory in vaccine
evaluation.
Objective: The present study was conducted to standardize a protocol for quality control and
evaluation of the recombinant HVT-H5 vaccine.
Methods: The protocol was designed for evaluation of H5 identity besides regular vaccine safety,
purity and potency. The identity of H5 insert was evaluated using real-time PCR while the vaccine
potency was evaluated using HVT virus titration, reduction of viral shedding during challenge test.
Results: Five vaccine batches were selected randomly and coded as A, B, C, D and E; these were
examined and proved to be identical by quantitative real- time PCR in which the H5 gene titer was
7.364, 7.499, 7.767, 8.049, 8.000 logs 10 copies / ml respectively. The result of in- house ELISA was
not significant for H5 gene detection and titration using polyclonal H5 serum. The HVT titer in CEF
was 3045, 3200, 3400, 3750 & 4000 PFU/dose for batch A, B, C, D, and E respectively. The selected
batches safety was satisfactory by 10 fold field doses injection in SPF chicks. The challenge test results
revealed 80% protection for A, B and C batches while D and E batches gave 90% protection. The
shedding of challenge virus was significantly low with mean of 2 logs 10 in the vaccinated group
compared with control group.
Conclusion: the developed evaluation protocol could depend mainly on q PCR for identity and
titration of H5 insert gene in addition to vaccine safety and efficacy.
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January 2017
Vol. 1, Iss. 1, Pages 1-162
