Abstract
Antibodies were raised in rats against the poliovirus type 1 capsid proteins, VP1, VP2 and VP3. Antibodies directed against VPI from type 1 poliovirus (Mahoney) neutralized type 1 but not type 2 poliovirus. Antibodies raised against VP2 and VP3 failed to neutralize type 1 virus. Thus, VP1 appears to be a neutralizing antigen for poliovirus and in its denatured form presents to the immune system its neutralizing determinants.