eba175

EBA-175, short for erythrocyte binding antigen 175, is a 175-kilodalton merozoite surface protein of the human malaria parasite Plasmodium falciparum. It belongs to the erythrocyte-binding-like (EBL) family of invasion ligands and is encoded by the eba-175 gene. The protein is expressed late in the parasite’s schizont stage and localizes to the merozoite surface, where it participates in the invasion of red blood cells.

The primary function of EBA-175 is to mediate erythrocyte entry by binding to glycophorin A on the surface of human erythrocytes. This interaction contributes to the sialic acid–dependent pathway of invasion, a route used by many P. falciparum strains. The extracellular region contains two Duffy-binding-like (DBL) domains within region II, with the second DBL domain (F2) implicated as the receptor-binding module. A transmembrane segment and a short cytoplasmic tail anchor the protein to the merozoite surface.

Genetic diversity in eba-175 is high, particularly in region II, leading to polymorphisms that can affect receptor binding and recognition by the host immune system. This diversity, along with redundancy among parasite invasion ligands, poses challenges for vaccine development. EBA-175 has been investigated as a vaccine antigen, often in combination with other invasion ligands, but efficacy in clinical trials has been limited by strain-specific responses and alternative invasion pathways.

Invasion of erythrocytes can proceed via multiple routes, and interactions with other ligands, such as PfRh5, can compensate when EBA-175 function is compromised, illustrating the complexity of P. falciparum merozoite entry.