Saul A, Lord R, Jones G, Geysen H M, Gale J, Mollard R
Queensland Institute of Medical Research, Brisbane, Australia.
Parasite Immunol. 1989 Nov;11(6):593-601. doi: 10.1111/j.1365-3024.1989.tb00923.x.
Monoclonal antibodies directed against the 51 kD merozoite surface antigen of Plasmodium falciparum also bind to other antigens within the infected cell. The sizes of these cross-reacting antigens have been characterized. Immunofluorescence due to the reaction of one of the monoclonal antibodies with these cross-reacting antigens was localized in the intra-erythrocytic parasite and in granules in the infected red cell cytoplasm. This immunofluorescence could be distinguished from the merozoite surface antigen in parasite lines with a variant serotype of the merozoite surface antigen which fails to react with the monoclonal antibodies. It was found that the in-vitro growth inhibition caused by the presence of one of the monoclonal antibodies, 8G10/48, was dependent on the expression of the corresponding serotype of merozoite surface antigen, a finding consistent with the inhibitory effect of this antibody being primarily directed against the merozoite surface antigen and not the cross-reacting antigens. Analysis of the frequency at which epitopes occur suggests that such cross-reacting proteins will be commonly seen in malaria, without the need to postulate a selective advantage for such cross-reacting specificities.
