Involvement of Malarial Proteases in the Interaction between the parasite and host erythrocyte in plasmodium knowlesi infections

Abstract

The effect of protease inhibitors obtained from the culture filtrates of actinomycetes(pepstatin, chymostatin, leupeptin, phosphoramidon and elastatinal)on the in vitro inbasion of erythrocytes from rhesus and assanese monkeys by plasmodium knowlesimerozoites was studied. The presence of these inhibitors had no effect on release of merozoites from schizonts but inhibited entry of the parasite into the red cell. Thus, at 50 ug/ml, ehymostatin and leupeption completely blocked the invastion where as pepstatien and elastatinal showed 59% inhibbition. Phosphoramidon at this concentration gave only 30% inhibition pretreatment of the erythrocytes with these inhibitors did not block invasion, Also the intracellular development of the parasite was totally unaffected in the presence of these agents.These results suggested that proteases of merozoites migth play sum crucial role in the invasion process.