Abstract: The invention comprises antigenic glycoproteins substantially similar to antigenic glycoproteins present on the surface of the merozoite form of Plasmodium falciparum, including glycoproteins of molecular weights of about 56,000 and about 50,000. The invention also comprises monoclonal antibodies which bind to the glycoproteins of the invention, hybridoma cell lines which are capable of producing these monoclonal antibodies, and vaccines and vaccine compositions comprising these glycoproteins or epitopes substantially similar to or cross reactive with these glycoproteins or genes or gene fragments encoding such epitopes.