Plasmodium berghei is immunomodulated by transgenic mouse interferon gamma leading to enhanced malaria protection in mice

Abstract

The aim of this study was to explore immunomodulatory potential of immunopotentiated Plasmodium berghei parasites in a murine malaria model with a view of contributing to malaria vaccine development strategies. Transfection was used to generate immunopotentiated Plasmodium berghei parasites through expression of mouse interferon gamma (mIFN-γ) in wild-type Plasmodium berghei parasites. Mice were inoculated with mIFN-γ expressing Plasmodium berghei parasites and treated. Another group of mice was inoculated with the parasite expressed mIFN-γ culture supernatants. The mice were later intraperitonially challenged with wild-type parasites. Sampling for cytokine and antibody assays was done and ELISA performed on the collected samples. Parasitaemia was monitored daily and survival time (days) recorded for the two sets of experiments. Analysis of variance (ANOVA) was used to analyze the results using graphpad instat software. There was a significantly higher level of IFN-γ (p < 0.001). The level of IL-4 was significantly low (p < 0.05). There was no significant difference in the levels of IgG (p = 0.0682). There was a 3 to 4 day delay in patent parasitaemia accompanied by reduced mean parasitaemia and improved survival of the mice. This study showed that interferon gamma expressing Plasmodium berghei immunomodulates malaria infection in mice leading to enhanced protection during challenge infection.