Onchocerca volvulus Ov-RAL-2 antigen (Ov-RAL-2)

Onchocerca volvulus Ov-RAL-2 is a recombinant protein antigen derived from the filarial nematode Onchocerca volvulus, which is the causative agent of onchocerciasis, also known as river blindness. It belongs to the retinol-binding protein-like (RAL) family and is primarily expressed in the hypodermis of the parasite's infective third-stage larvae (L3) and adult stages. Ov-RAL-2 is a leading candidate for a prophylactic vaccine, often developed as a bivalent formulation or a fusion protein (Ov-FUS-1) in combination with the Ov-103 antigen. Immunization with Ov-RAL-2 elicits a robust immune response characterized by high titers of cytophilic IgG1 and IgG3 antibodies in humans. These antibodies facilitate the elimination of L3 larvae through a mechanism involving antibody-dependent cellular cytotoxicity (ADCC), recruitment of neutrophils, and activation of the complement system. Preclinical studies in mice, cattle, and non-human primates have demonstrated that Ov-RAL-2-based vaccines can significantly reduce larval survival and adult worm burdens, supporting its potential as a critical tool for the elimination of onchocerciasis.

Other names

RAL-2Retinol-binding protein-like 2Onchocerca volvulus RAL-2Ov-FUS-1 (as part of a fusion protein)

Induction of antigen-specific IgG1 and IgG3 antibodies that mediate the killing of infective third-stage larvae (L3) through antibody-dependent cellular cytotoxicity (ADCC) involving neutrophils and the complement system.