ASTMH 2018, Teun Bousema: “Natural and vaccine-induced immunity against novel P. falciparum gamete targets”

In collaboration with ASTMH, Image Audiovisuals, and session presenters, MESA brings you this webcast from the 67th ASTMH annual meeting in New Orleans, October 2018

Title: “Natural and vaccine-induced immunity against novel P. falciparum gamete targets”

Speaker: Teun Bousema, Radboudumc, Nijmegen, Netherlands

Session information: 

Symposium 19: Transmission Blocking Immunity: From Biology to Interventions

October 29, 2018, 10:15 AM – 12:00 PM, Marriott – Mardi Gras D, 3rd floor

Abstract:

The recent decline in global malaria burden has stimulated increased efforts towards Plasmodium falciparum elimination, including a major focus on malaria transmission and transmission-blocking interventions. The highly efficient transmission of P. falciparum is considered one of the key challenges for elimination efforts. Infection with Plasmodium can elicit antibody responses that inhibit parasite survival in the human host or in the mosquito, where they are ingested in an infectious blood meal. Natural or induced antibody responses can have transmission reducing activity (TRA) and hence reduce or completely block transmission to mosquitoes. Historically, studies on TRA have been restricted to a small selection of gamete antigens that are expressed during parasite development in mosquitoes and interfere with parasite fertilization or later development in mosquitoes. The most advanced vaccine candidate with TRA, post-fertilization antigen Pfs25, was recently tested in an endemic setting with sobering results. This highlights the need for a more comprehensive search for candidate antigens involved in TRA and the exploration of novel strategies to reduce transmission. Recently, the portfolio of ‘traditional TRA antigens’ (i.e. antigens involved in parasite fertilization or further development in mosquitoes) has been expanded by a large-scale screening of immune profiles of individuals with naturally acquired TRA. The first results of pre-clinical evaluation of newly identified antigens have very recently become available and highlight the potential of some hits. In addition, the first evidence has been generated for a potent naturally acquired response that may interfere with gametocyte maturation or circulation prior to ingestion by mosquitoes. Antigens have been identified and associated with gametocyte phagocytosis. Lastly, the interaction between gametocyte/gamete antigens and mosquito immunity is an area of increasing interested and emerging insights. Specifically, it was recently uncovered that the gametocyte/gamete Pfs47 protein is involved in parasite strategies to escape mosquito innate immunity that can interfere with parasite development in mosquitoes. This symposium presents recently published and unpublished data on all these aspects of human and mosquito immunity that interferes with transmission. The symposium content will range from biological characterization of antigens and mechanisms of TRA to early results of immunization experiments and the future use scenarios of interventions that aim to elicit TRA.