Production and characterization of a monoclonal antibody that recognizes the fragment of 28-30 kDa of the protein MSP-1 from Plasmodium falciparum

Abstract

Merozoites of the malaria parasite Plasmodium falciparum have on their surface proteolytic processed fragments of MSP-1 (merozoite surface protein-1). These fragments have relative molecularweights of approximately 83, 42, 38, 28-30 kDa, respectively In this study we describe the characterization of a monoclonal antibody. denominated 8F4, that recognizes MSP-1 based upon the following characteristics: 1) subcellular location of the antigen, 2) relative molecular weight, 3) time of expression during the asexual life cycle of the parasite, 4) the association of the protein with the plasma membrane and 5) epitopes shared with MSP-1. In addition, it was found that 8F4 recognizes the 28-30 kDa fragment that arises as a consequence of the first proteolyiic processing of MSP-1. The study confirms that such fragment is excluded from the merozoite surface during invasion, suggesting that it makes part of a complex of polypeptides which is released from the merozoite before the invasion process takes place. This is the first report of a monoclonal antibody which specifically recognizes this polypeptide.