Antigenic and immunogenic properties of inactivated polio vaccine made from Sabin strains.

Inactivated polio vaccine (IPV) was prepared with the Sabin strains, normally used for the attenuated live vaccine. The vaccine was characterized with respect to its antigenicity as determined by ELISA and biosensor analysis and its immunogenicity in rats. Compared with the vaccine prepared with virulent strains (Mahoney, MEF and Saukett) some distinct differences were found with regard to the interaction with glass vials (types 1 and 2) and antigenicity (type 3). The most profound difference however, was the immunogenicity of types 1 and 2. Standardized on the amount of virus, type 1 Sabin-IPV was about 3 times more immunogenic as compared to Mahoney-IPV. The immunogenicity of type 2 Sabin-IPV on the other hand was reduced approximately 10-fold, compared to MEF-IPV. Type 3 Sabin and Saukett IPV were comparable in immunogenicity but differences in antigenicity were evident. The lack of correlation between antigenicity and immunogenicity demonstrate that current IPV standards are not suitable to quantify IPV made from Sabin strains. The results indicate that future Sabin-IPV vaccines may have to contain virus amounts that are very different as compared to current IPV vaccines.