Rapid Fire Presentation 8th International Conference on Plasmodium vivax Research 2022

Identification of naturally acquired transmission-blocking antibodies against Plasmodium vivax (#208)

Sataporn Thongpoon 1 , Wanlapa Roobsoong 1 , Wang Nguitragool 2 , Sadudee Chotirat 1 , Takafumi Tsuboi 3 , Eizo Takashima 3 , Liwang Cui 4 , Tomoko Ishino 5 , Mayumi Tachibana 6 , Jetsumon Prachumsri 1
  1. Mahidol Vivax Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Please Select, Thailand
  2. Department of Molecular Tropical Medicine and Genetics, Faculty of Tropical Medicine, Mahidol University, Bangkok, Please Select, Thailand
  3. Division of Malaria Research, Proteo-Science Center, Ehime University, Matsuyama, Japan
  4. Department of Internal Medicine, Morsani College of Medicine, University of South Florida, Tampa, Florida, United States
  5. Department of Parasitology and Tropical Medicine, Tokyo Medical and Dental University, Tokyo, Japan
  6. Division of Molecular Parasitology, Proteo-Science Center, Ehime University, Matsuyama, Japan

Plasmodium vivax is responsible for the majority of malaria cases found in South East Asia and other regions outside Africa. To achieve malaria elimination by 2030, the transmission-blocking vaccine (TBV) has been identified as a potential tool to be integrated into the malaria elimination package. As transmission-blocking immunity (TBI) can be induced after episodes of malaria, this study aimed to identify and characterize the naturally acquired transmission-blocking immunity in the endemic population. In total, 39 P. vivax patient plasma samples were examined by the direct membrane feeding assay to determine the level of naturally-acquired transmission-blocking activity. Among these, 25 showed 10%-100% transmission-blocking activity. The blocking activity against heterologous isolates was identified in 20 out of 25 plasma samples. Using the AlphaScreen platform, these plasma samples were screened against a panel of 342 P. vivax recombinant proteins to identify vaccine targets whose total IgG or IgM response is associated with transmission-blocking. New targets were identified, along with the well-established vaccine candidate Pvs230 which provides the validation for the screening approach.