CAPSID DESTABILIZATION IS REQUIRED FOR ANTIBODY-MEDIATED DISRUPTION OF POLIOVIRUS

Three out of 36 poliovirus type 1-specific monoclonal antibodies which , at 37 degrees C in a medium of normal ionic strength (mu = 0.16), ca used only aggregative neutralization (reversible by immune complex dis sociation at pH2) shifted to cause disruptive, acid-irreversible neutr alization when the temperature was raised to 39 degrees C or the ionic strength was lowered to 1/100 of normal. Under both conditions, the a ntigenic conversion was stoichiometric, but the efficiency was lower a t 39 degrees C than at low ionic strength. Antigenic conversion and ir reversible neutralization under both conditions were inhibited by WIN 51711, a capsid-stabilizing compound. Complete inhibition required fil ling of most of the virion's binding pockets by this compound.