Publication: Evaluation of Plasmodium vivax HAP2 as a transmission-blocking vaccine candidate
2
Issued Date
2020-03-17
Resource Type
ISSN
18732518
0264410X
0264410X
Other identifier(s)
2-s2.0-85079861419
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Mahidol University
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SCOPUS
Bibliographic Citation
Vaccine. Vol.38, No.13 (2020), 2841-2848
Suggested Citation
Yue Qiu, Yan Zhao, Fei Liu, Bo Ye, Zhenjun Zhao, Sataporn Thongpoon, Wanlapa Roobsoong, Jetsumon Sattabongkot, Liwang Cui, Qi Fan, Yaming Cao Evaluation of Plasmodium vivax HAP2 as a transmission-blocking vaccine candidate. Vaccine. Vol.38, No.13 (2020), 2841-2848. doi:10.1016/j.vaccine.2020.02.011 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/53565
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Title
Evaluation of Plasmodium vivax HAP2 as a transmission-blocking vaccine candidate
Abstract
© 2020 The Author(s) Transmission-blocking vaccine (TBV) is a promising strategy to interfere with the transmission of malaria. To date, only limited TBV candidate antigens have been identified for Plasmodium vivax. HAP2 is a gamete membrane fusion protein, with homology to the class II viral fusion proteins. Herein we reported the characterization of the PvHAP2 for its potential as a TBV candidate for P. vivax. The HAP2/GCS1 domain of PvHAP2 was expressed in the baculovirus expression system and the recombinant protein was used to raise antibodies in rabbits. Indirect immunofluorescence assays showed that anti-PvHAP2 antibodies reacted only with the male gametocytes on blood smears. Direct membrane feeding assays were conducted using four field P. vivax isolates in Anopheles dirus. At a mean infection intensity of 72.4, 70.7, 51.3, and 15.6 oocysts/midgut with the control antibodies, anti-PvHAP2 antibodies significantly reduced the midgut oocyst intensity by 40.3, 44.4, 61.9, and 89.7%. Whereas the anti-PvHAP2 antibodies were not effective in reducing the infection prevalence at higher parasite exposure (51.3–72.4 oocysts/midgut in the control group), the anti-PvHAP2 antibodies reduced infection prevalence by 50% at a low challenge (15.6 oocysts/midgut). Multiple sequence alignment showed 100% identity among these Thai P. vivax isolates, suggesting that polymorphism may not be an impediment for the utilization of PvHAP2 as a TBV antigen. In conclusion, our results suggest that PvHAP2 could serve as a TBV candidate for P. vivax, and further optimization and evaluation are warranted.