Antigenic analysis of poliovirus type 3 using monoclonal antibodies

Hybridoma cell lines secreting monoclonal antibodies to type 3 poliovirus have been prepared and their reactivity with infectious virus ('D' antigen), empty particles ('C' antigen) and isolated virus capsid proteins examined. Eight antibodies reacted with epitopes common to 'D' and 'C' antigen and all of these possessed high titres of neutralizing activity. However only 12 out of 19 antibodies which reacted exclusively with 'D' antigen neutralized virus infectivity and some of these reacted only with strains of virus with T1 oligonucleotide maps identical or similar to that of Sabin vaccine virus. These antibodies will be of value in identifying strains of virus derived from Sabin vaccine. None of the 20 monoclonal antibodies which neutralized type 3 poliovirus strains reacted in immunoblot experiments with isolated virus capsid proteins. However, 6 of the 24 antibodies which reacted only with non-infectious 'C' antigen bound to VP1 and VP3 and 3 of these antibodies also reacted with proteins of types 1 or 2 poliovirus. The lack of reactivity of neutralizing monoclonal antibodies with isolated viral proteins suggests that the antigenic properties of proteins are determined by their arrangement in the virus.