Development and optimizing a simple and cost-effective medium for in vitro culture of Plasmodium berghei-ANKA strain with conserving its infectivity in BALB/c mice.

OBJECTIVES: The current culture system for P. berghei still requires modifications in consistency and long-term maintenance of parasites considering their pathogenicity in culture media. Therefore, this study designed to further improvement of culture conditions and designing a cost-effective culture medium with minimum changes in pathogenicity for in vitro culture of P. berghei. RESULTS: Results indicated that the rate of parasitaemia in our modified method remained statistically stable between days one to seven (P = 0.07). The current modified cultivation method was more efficient in maintaining of parasites for further days. Furthermore, in current method the stability of parasitaemia rate during day1 to day7 was in better rate compared to that in Ronan Jambou et al. and the differences between two methods were statistically significant (P = 0.001). The virulence of cultivated parasites in our modified method remained similar to frozen stock parasites as positive control group. No significant differences were seen in survival time between two groups of mice those were infected with either cultivated parasites or stock freeze parasites (P = 0.39) with the mean survival time of 20.83 ± 3.84 and 19.66 ± 1.21 days, respectively. Herein, we achieved a simple, cost-effective and applicable technique for culture of P. berghei.

Genetic diversity of transmission blocking vaccine candidate (Pvs25 and Pvs28) antigen in Plasmodium vivax clinical isolates from Iran.

The leading candidates for a Transmission Blocking Vaccine (TBV) in Plasmodium vivax parasite are the ookinete surface protein 25 (Pvs25) and Pvs28, which their phase I clinical trial is ongoing. Therefore, we carried out survey of polymorphisms of the pvs25 and pvs28 genes in P. vivax populations that are circulating in the two malaria areas of contrasting endemicity in Iran, before field application of the TBV. To characterize the polymorphisms of pvs25 and pvs28 genes, 50 isolates were analyzed by sequencing method and their gene structure was compared with parasite populations from India, Bangladesh, Indonesia, Thailand, Mexico and Brazil. Three mutations were detected in pvs25 and pvs28 including Q87K, E97Q, I130T and M52L, T65K, T140S with two and four distinct haplotypes, in comparison with the Sal I sequence type, respectively. Both haplotypes of Pvs25 were found among northern and southern P. vivax isolates; however, only two and three of the Pvs28 variants were observed among the northern and southern isolates, respectively. In conclusion, the present results show the limited sequence polymorphism of the pvs25 and pvs28 genes among field P. vivax population in Iran. These results highly encourage with respect to applicability of Pvs25 and Pvs28-based vaccine against P. vivax infection in the region, where these parasites are prevalent, whether these occur in the temperate or tropical zones.