The C-terminal region of Plasmodium vivax merozoite surface protein 1 (PvMSP-119) is a leading vaccine
candidate for inclusion in a polyvalent malaria vaccine. In the present study, the IgG subclasses profile and
the avidity of IgG to PvMSP-119 were evaluated in individuals (n = 94) naturally exposed to P. vivax parasite
in malaria endemic areas in Chabahar districts, Iran. In individuals with patent P. vivax malaria, 86.1%was
sero-positive to PvMSP-119 and IgG1 (81.9%) was the predominant subclass. In addition, to determine
the persistence of specific IgG, IgG1 and IgG3 antibodies to PvMSP-119, the frequency of antibodies was
determined in the infected subjects (n = 74) after treatment with standard chloroquine and itwas detected
that the frequency of responders was significantly reduced to 51.3%, 51% and 16.2%, respectively. The
antigen-binding avidity of IgG antibodies to PvMSP-119 was measured in sero-positive sera and the highavidity
of IgG, IgG1 and IgG3 was found in 66.6%, 61% and 47% of the infected subjects with P. vivax,
respectively. The present result shows that individuals who exposed to vivax malaria in the endemic
region in Iran develop antibodies with high-avidity to PvMSP-119. These results could help to understand
the interactions between the host and P. vivax parasite in development of MSP-119-based vaccine.
کلید واژگان :
Malaria Plasmodium vivax C-terminal region of MSP-1 Antibody Avidity Immune response
