Rodent malaria species Plasmodium berghei have been widely used to validate vaccine development including its storage. Therefore,the effects of cryopreservation and irradiation of P. berghei towards its infectiveness and protein profiling were studied. A group of mouse was injected intraperitonealy with 0, 150, 175 and 200 Gy gamma irradiated P. bergheithat had been cryopreserved for 1 month. As comparison, the infectiveness of irradiated parasites stored in freezer (-20oC) and ultra low temperature (-80oC) for the same time was also evaluated. The capability of parasite to infect mouse was determined by counting the parasites number in red blood cells drawn from tail by making thin blood smear stained with Giemsa. Protein profile in the blood was analyzed with SDS-PAGE method. It was found that the storage did alter the ability of the irradiated parasites to induce infection in the recipient animals. After one month observation, it was demonstrated that all mice from different treatment groups showed negative parasitemia in their blood. This might have beeen caused by the death of the parasites or the erythrocytes, where the parasites were hosted, due to physical damage after irradiation and very low temperature storage. However, non irradiated parasites (control) were still infective in mouse even though it required longer to establish an infection.It is suggested that the condition of the sample prior to preservation was another factor that need to be considered. Further analysis demonstrated that the protein profile was maintained throughout the storage time. It was concluded that the storage influenced the performance characteristics of vaccine materials for immunization.

Full text: IJEIR_1576_Final.pdf