Abstract
At physiological ionic strength, monoclonal antibody 35-1f4 has previously been shown to neutralize poliovirus type 1 by antibody-mediated polymerization. At low ionic strength, this antibody neutralized the virus by a hit-and-run mechanism: the virions were converted to non-infectious, empty capsids devoid of antibodies. These empty capsids resembled those formed by thermal denaturation of native polio virions in their sedimentation coefficient (80S), antigenicity (H) and isoelectric pH (6.3).