Studies on inactivated vaccines of rift valley fever virus

A trial to improve the already used and locally produced inactivated RVF vaccine was attemted. This necessitated to study many combinations and various parameters including:The cell type, system of growing the cell culture, the MOl,influence of DE.~dextran on the final virus titer, amount of A1(OH)3 to be incorporated in the vaccine, methods to evaluate the vaccine, influence of tBe inoculated dose on the immune response andtec tion. The conclusions of the results obtained in the present investigation could be summarized as follows.1- The infectivity titration of RVF virus conducted in both mice and different types of cell cultures showed that the highest log10 titer was obtained in CER cell line (7.6 TClD50) which was almost equal to the intraperitoneal titer in mice but one loglO titer in suckling mice.2- By using MOl values from 2-5, we got the optimal TCID50 per m1. while with MOl doses of 1 or 7 there was loglOreduction in titers of about 0.7 and 0.4 in BHK and reduction of 0.8 and 0.5 in CER cell respectively.3- Absence of serum in maintenance medium increased the infectivity titer by 0.5-0.9 and 0.4-0.7 in CER andBHK cells respectively. On the ather band the estimated titer in mice showed an incrrease when serum was present inthe diluent.