Intracellular proteolysis of poliovirus eclipse particles is abortive.

A series of weak bases and the ionophore monensin were tested for their effect on the intracellular processing of type 1 poliovirus in HeLa cells. At concentrations that did not inhibit plaque formation or viral protein synthesis, the compounds suppressed the proteolytic processing of 135S particles and the formation of 110S particles. In addition, some compounds strongly reduced transit of modified particles to the lysosomes. These results suggest that transit to lysosomes and proteolysis of subviral particles are not essential steps in the infectious pathway. The role of 135S particles as intermediates in infection is discussed.