Effect of chloroquine on lysosomes and on growth of mouse hepatitis virus (MHV-3).

After a 6-hour treatment with chloroquine, infected mouse peritoneal macrophages produce markedly less mouse hepatitis virus than untreated cells. Macrophages maintained in culture for 72 hours after the treatment produce a higher virus yield. Cytochemical investigations immediately and 3 days after chloroquine treatment show an increased permeability of the lysosomes of the latter. Variations of the enzymes escaping from the lysosomes are thought to be responsible for differences in virus uncoating and consequent virus yield.