The determination of antigenic potency of poliomyelitis vaccine by measuring its antibody-combining capacity.

A modification is described of the antibody-combining test originally introduced by the author in 1955. The reaction between antigen and antibody has been shown to be type specific, reproducible and relatively precise if the plaque technique is used for the titration of infective virus. Though the data available at present suggest that the antibody-combining capacity of a vaccine as titrated by this method parallels the antigenic activity measured in vivo, more information is necessary to give conclusive evidence on the relation between antigenic potencies titrated in vitro and in vivo.