Oral Presentation Australian Society for Microbiology Annual Scientific Meeting 2019

Exploring merozoite surface protein 2 function and vaccine potential during malaria red blood cell invasion. (#35)

Isabelle Henshall 1 , Gaoqian Feng 2 , James Beeson 2 , Danny Wilson 1
  1. Research Centre for Infectious Diseases, School of Biological Sciences, University of Adelaide, Adelaide, SA, Australia
  2. Malaria Immunity and Vaccines Group, Burnet Institute, Melbourne, VIC, Australia

Malaria parasites that invade and multiply in red blood cells (RBCs) cause >200 million cases of disease each year, with children <5 years most at risk of dying from infection. Plasmodium falciparum parasites cause the majority of malaria related mortality. Development of a highly efficacious vaccine is essential for long-term malaria control and eradication. Blocking the malaria parasites’ merozoite from entering the RBC prevents establishment of parasite infection and growth of the disease-causing stage of the lifecycle. Vaccines raised against P. falciparum merozoite surface protein 2 (MSP2) have been shown to protect against infection in a clinical trial. To characterise the role of PfMSP2 and its potential as a vaccine target, a transgenic line expressing PfMSP2 under control of an inducible knockdown system was generated and the impact PfMSP2 loss of function assessed. While substantial knockdown of PfMSP2 protein expression is achieved parasite growth remains unperturbed, suggesting minimal PfMSP2 is required for growth. An initial screen of sera from malaria immune Papua New Guinean adults using this PfMSP2 knockdown line allowed us to explore levels of neutralising and complement-activating antibodies in the immune sera directed against PfMSP2 and total merozoite antigens. The development of these tools aid our understanding of the biological function of PfMSP2 and highlight the utility of transgenic parasite lines in studying antibody responses against major vaccine candidates.