We assessed the safety, tolerability, and immunogenicity of a mixture of three synthetic peptides derived from the Plasmodium vivax circumsporozoite protein formulated in Montanide ISA 720 or Montanide ISA 51.
Clinical manifestations of malaria and parasitemia were monitored beginning 7 days post-challenge. All Duffy (+) volunteers developed patent malaria infection within 16 days after challenge.
Results of this study provide evidence that Pv200L is a naturally immunogenic fragment of the PvMSP-1 and is associated with the degree of exposure to parasites.
Immunity to malaria is widely believed to wane in the absence of reinfection, but direct evidence for the presence or absence of durable immunological memory to malaria is limited.
This study showed that the parascreen pan/pf based strategy should be the preferred option to be used at health post level in rural Tigray. This finding is relevant nationwide as the entire country's malaria epidemiology is similar to the study area.
Our results indicates that PvMSP3 is highly immunogenic in naturally exposed populations, where 78% of studied individuals present IgG immune response against the full-length recombinant protein (PVMSP3-FL) and IgG subclass profile was similar to all five recombinant proteins studied with a high predominance of IgG1 and IgG3.
Variable loop 3 (V3) of HIV-1 SU and subdomain 1 of the Plasmodium vivax DBP share a sequence similarity. The site of amino acid sequence similarity was necessary, but not sufficient, for DARC binding and contained a consensus heparin binding site essential for DARC binding. Both HIV-1 and P. vivax can be blocked from binding to their chemokine receptors by the chemokine, RANTES and its analog AOP-RANTES.
These results indicate that antibody titers obtained using IFAT may provide useful information about the prevalence of P. vivax in low endemic areas and could be used to detect asymptomatic patients. Finding asymptomatic patients is important in eliminating vivax malaria in South Korea.
In Peru, the P. vivax recurrent infections were common and displayed a high turnover of parasite genotypes compared to day 0.
Tryptophan-rich proteins from several malarial parasites have been identified where they play an important role in host-parasite interaction.