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

Determining diversity and immune selection targets of leading Plasmodium vivax antigen vaccine candidates and sero-surveillance markers (#407)

Alison Paolo N Bareng 1 2 , Myo Naung 1 2 3 4 , Somya Mehra 1 2 , Alyssa E Barry 1 2 3 4
  1. Institute for Mental Health and Physical Health and Clinical Translation (IMPACT), School of Medicine, Deakin University, Geelong, VIC, Australia
  2. Life Sciences Discipline, Burnet Institute, Melbourne, Victoria, Australia
  3. Division of Population Health and Immunity, Walter and Eliza Hall Institute of Medical Research, Melbourne, Victoria, Australia
  4. Department of Medical Biology, University of Melbourne, Melbourne, Victoria, Australia

Background:

One of the major gaps in Plasmodium vivax (Pv) research is the lack of information on the diversity of antigens, which could provide relevant details on vaccine development against Pv. Population genetics can not only assess transmission intensity but also provide insights in detecting genes under immune selection. We, therefore, aimed to determine the global distribution of antigen diversity and identify gene regions with signature of immune selection amongst leading Pv vaccine candidate antigens and sero-surveillance markers. 

Methods:

Several signatures of diversity and balancing selection were measured based on published sequences from multiple geographic populations. Genetic relatedness of the sequences was visualized through haplotype network diagrams. Furthermore, sequences were mapped onto experimentally defined three-dimensional protein structures to analyze spatially derived nucleotide diversity and immune selection hotspots.

Results and conclusion:

Initial results showed low nucleotide and haplotype diversity in Pv antigen genes rama, msp119, and csp. In contrast, high diversity was observed in genes rbp1a, rbp2b, dbpRII, and ama1. Lastly, spatially-derived nucleotide diversity and Tajima’s D of some Pv antigens vary geographically which may indicate unique parasite adaptations to different host environments. Information from this study will guide researchers in designing widely effective vaccines and serological tools against Pv parasites.