Journal of Bacteriology & Parasitology

Abstract

Effect of Immunization with Cysteine Protease from Phase-Separated Parasite Proteins on the Erythrocytic Stage Development of the Chloroquine-Resistant, Plasmodium berghei in BALB/C Mice

Amlabu Emmanuel, Andrew. J.Nok, Inuwa H. Mairo2, Akin-Osanaiye B. Catherine and Haruna Emmanuel

Crude preparations of malaria parasite proteins from the hydrophobic and hydrophilic phases were made by Triton X-100 temperature-induced phase separation procedures. Cysteine protease was purified from the hydrophobic phase of the parasite protein preparation. Groups of BALB/c mice were immunized intraperitoneally with the purified cysteine protease and crude preparations of the parasite proteins respectively. Priming and booster immunizations were administered on days 0, 14 and 21 prior to lethal parasite challenge on day 30. The course of infection was monitored by microscopic Giemsa-stained, thin blood smears. Protection was conferred at varying thresholds in the groups of mice immunized. This was shown by a week delay in the onset of parasitemia and red blood cell invasion by parasites in the group of mice immunized with the purified cysteine protease. Pack Cell Volume, parasite burden and the mean survival time of mice in days post-infection when compared to experimental controls indicated that protection was conferred in mice during immunization. Our data shows that the parasite enzyme cysteine protease is a potential target which can further be exploited for precise drug targeting and vaccine development against malaria.