A comparative study of a plaque and quantal method for assaying the neutralizing activity of antisera to type 1 poliovirus

Abstract

Sera from two rabbits bled after one, two and three inoculations of concentrated type 1 poliovirus tissue culture fluid were assayed for neutralizing activity by a quantal and a plaque method. The plaque counts in these tests have been shown to approximate to a Poisson distribution as determined by the relationship between the variance and the mean of replicate counts. However, there is a considerable scatter of the points in such a comparison and this accounts for the absence of the expected increase in accuracy of this plaque method over the quantal.The relationship between the antibody content of the sera determined by the two methods is non-linear. This can be attributed to inhomogeneity of the antibody produced which increases with the number of antigenic stimuli given.