Lack of quantitative correlation between the neutralization of poliovirus and the antibody-mediated pI shift of the virions.

The effect of mono- and polyclonal antibodies on the infectivity and pI (isoelectric pH) of type 1 poliovirus was studied. According to Mandel's hypothesis, the isoelectric pH of poliovirus should change to about pI 4 upon neutralization. However, several antibodies did not follow this rule. Moreover, when antibodies did shift the pI, no quantitative correlation existed between the extent of neutralization and the amount of poliovirus shifted to low pI.