Neutralization kinetics studies with type SAT 2 foot-and-mouth disease virus strains:II. Antigenic differentiation of vaccine strains

A comparison of homologous and heterologous rates of neutralization demonstrated that antigenic relationships of foot-and-mouth disease virus strains could be differentiated quantitatively by the kinetics of neutralization method described previously (Rweyemamu, Booth & Pay, 1977). Conventional formulae for r, R and D values could be applied to results obtained by this method. It was demonstrated that results analysed this way gave R values which were similar to those obtained with other neutralization test methods but which were generally smaller than those obtained with complement fixation test results. It was demonstrated that there were wide differences between the vaccine strains tested as demonstrated by R value relationships. An examination of r values, however, demonstrated that antisera to the Moz 1/70 strain were highly reactive with most of the virus strains from Central and Southern Africa. The selection of FMD virus strains with a wide serological range for vaccine production is discussed.