A conformational epitope in placental malaria vaccine antigen VAR2CSA: What does it teach us?
In:
Affiliations
- [1] NIAID, Lab Malaria Immunol & Vaccinol, NIH, Bethesda, MD 20892 USA [NORA names: United States; America, North; OECD]
- [2] NIAID, Lab Malaria Immunol & Vaccinol, NIH, Bethesda, MD 20892 USA [NORA names: United States; America, North; OECD]
- [3] Rigshosp, Dept Infect Dis, Copenhagen, Denmark [NORA names: Capital Region of Denmark; Hospital; Denmark; Europe, EU; Nordic; OECD]
- [4] Rigshosp, Dept Infect Dis, Copenhagen, Denmark [NORA names: KU University of Copenhagen; University; Denmark; Europe, EU; Nordic; OECD]
Abstract
VAR2CSA is the Plasmodium falciparum variant surface antigen that mediates binding of infected erythrocytes to chondroitin sulfate A (CSA) and their sequestration in intervillous spaces of the placenta, leading to placental malaria (PM). Relatively high polymorphism in VAR2CSA sequences has hindered development of a vaccine that induces broadly neutralizing immunity. Recent research has highlighted that a broadly reactive human monoclonal antibody, called PAM1.4, binds to multiple conserved residues of different subfragments of VAR2CSA, forming a conformational epitope. In this short perspective, we describe evidence that residues located in the interdomain-1 fragment of VAR2CSA within the PAM1.4 binding epitope might be critical to broad reactivity of the antibody. Future investigation into broadly reactive anti-VAR2CSA antibodies may be important for the following: (1) identification of similar conformation epitopes targeted by broadly neutralizing antibodies; and (2) understanding different immune evasion mechanisms used by placenta-binding parasites through VAR2CSA polymorphism in critical epitopes.