Evidence for secondary structure in poliovirus virion RNA demonstrated by antibodies against double-stranded RNA.

Poliovirus particle RNA has been considered to have little secondary structure. Specific binding of poliovirion RNA by antibodies against double-stranded RNA (dsRNA) has been confirmed and further characterized by a radioimmunoassay using Staphylococcus aureus protein A to precipitate the nucleic acid-antibody complex. Competitive binding studies between virion single-stranded RNA (ssRNA) and poly(I).poly(C) demonstrated that the dsRNA effectively inhibited binding of radiolabelled poliovirion RNA by the anti-dsRNA antibodies but the virion RNA was a poor competitor of radiolabelled ds RNA. This indicates that both RNAs reacted with the same species of antibodies in the sera, but avidity of the antibodies for dsRNA was greater than for the poliovirion RNA.