Trials for increasing the infectivity titer of fowl pox vaccines prepared on SPF embroynated chicken egg and tissue culture

Abstract

The present work was designed to study the effect of DEAE-dextran and Magnesium Chloride (MgCl) on fowl pox virus vaccine (FPV) in order to obtain a maximum titer allowing the massive production of the vaccine. Fowl pox virus; used for vaccine production; was propagated on embroynated chicken eggs (ECE) and chicken embryo fibroblast (CEF), the virus was inoculated in ECE and CEF without DEAE-dextran nor MgCl, and with DEAE-Dextran and MgCl separately. The time of harvestion was early as one day post inoculation in CEF. The virus titer were higher in case of treated inoculums with DEAE-dextran and MgCl reaching (6.2 and 7.5 log10TCID50/ml respectively) on CEF and (6.2 and 6.7 Log10EID50 respectively) on ECE. Fowl pox vaccines (FPV) were prepared before and after DEAE-Dextran and MgCl treatment. The application of quality control assays revealed the safety, sterility and potency of the prepared vaccines. Immune response of the prepared FPV vaccines were evaluated in chickens using virus neutrization test (VNT). It was found that, the use of DEAE-Dextran and MgCl with the recommended concentrations could result in increasing the virus titer with reduction in the time of harvestation and accordingly increase the vaccine production and decrease its cost.