Transferrin receptor 1 is a reticulocyte-specific receptor for Plasmodium vivax

P. vivax is notorious for its strong preference for young red blood cells (reticulocytes). In 1992, Galinski and her team first reported identification of P. vivax proteins responsible for recognising the reticulocytes (Galinsky et al, Cell, 1992). They named these proteins the Plasmodium vivax Reticulocyte binding proteins (PvRBPs). However, their cognate receptors on the surface of reticulocytes had since remained elusive, until earlier this year when Gruszczyk et al reported their discovery of specific interaction between PvRBP2b and a reticulocyte specific surface protein, the transferrin receptor 1 (TfR1 or CD71). TfR1 is abundant in reticulocytes but completely absent from mature erythrocytes. The PvRBP2b-TfR1 interaction provides a clear explanation for the strong reticulocyte preference of P. vivax and helps solve, at least partially, a decades long fundamental question. The researchers also showed that this interaction can be blocked by antibodies, leading to inhibition of parasite invasion. Whether other PvRBPs can substitute PvRBP2b by recognising the same or an alternate reticulocyte receptor is unclear. This finding has broken a new ground for research into P. vivax vaccine development aiming to halt the parasite right before it invades.