Development of quantitative receptor-ligand binding assay for use as a tool to estimate immune responses against...

Antibodies generated against Region II of Plasmodium vivax Duffy binding protein (PvRII) can block binding of this parasite ligand to its receptor, the Duffy antigen receptor for chemokines (DARC), and prevent erythrocyte infection by the parasite. An in vitro functional assay that can serve as an immune correlate of an antigen activity is an important tool to guide vaccine development. We describe here the development of a quantitative binding assay and its use to study immune responses against PvRII. The assay was used to test anti-PvRII mouse sera, and was found a useful tool for quantitative estimation of anti-PvRII blocking antibodies.