Optimisation and comparison of different methods for antigen extraction from oil adjuvant inactivated infectious bursal disease vaccine

Antigenic quantification based in vitro method for potency estimation of oil adjuvant inactivated vaccine requires a suitable antigen exaction protocol for maximum recovery of antigen from the vaccine. To find out the suitable protocol, in the present study, seven different organic solvents including isopropyl Myristate (IPM), isopropyl Palmitate (IPP), benzyl alcohol, butanol, acetone, chloroform/methanol and dimethyl sulphoxide (DMSO) were tested to recover the antigen from the six oil adjuvant inactivated infectious bursal disease (IBD) and two Newcastle disease (NDV) vaccines from different manufacturers. The mean OD450 values of antigen extracted from all the vaccines using different organic solvents were determined by in house developed sandwich ELISA (sELISA). The mean average ODs of all six IBD vaccines were 2.794, 2.520, 2.690 and 2.359, respectively from IPM, IPP, benzyl alcohol and butanol methods. Antigen recovered by acetone, chloroform/methanol and DMSO methods gave ODs value of 0.019, 0.203 and 0.062, respectively. Based on the sELISA results, IPM and IPP methods were found as most appropriate for antigen extraction from oil adjuvant IBD vaccine. The antigen recovery was further confirmed by protein estimation of antigen recovered by IPM and IPP. The results of the present study indicated that IPM and IPP were the two appropriate organic solvents for antigen extraction from oil adjuvant IBD vaccine.