RIFIN, a large family of Plasmodium variant surface antigens, plays a crucial role in malaria pathogenesis by mediating immune suppression through activation of inhibitory receptors such as LAIR1, and antibodies with LAIR1 inserts have been identified that bind infected erythrocytes through RIFIN. However, details of RIFIN-mediated LAIR1 recognition and receptor activation have been unclear.
Plasmodium falciparum causes the most severe form of malaria. Acquired immunity against P. falciparum provides insufficient protection even after repeated infections. Therefore, P. falciparum parasites might exploit inhibitory receptors for immune evasion. P. falciparum RIFINs are products of a multigene family consisting of 150-200 genes.
The malarial parasite Plasmodium exports its own proteins to the cell surfaces of red blood cells during infection. Examples of exported proteins include members of the repetitive interspersed family (RIFIN) and sub‐telomeric variable open reading frame (STEVOR) family of proteins from Plasmodium falciparum.