Clonal diversity in a single isolate of the malaria parasite Plasmodium falciparum

This work was supported by grants from the Wellcome Trust, UNDP/World Bank/WHO Special Programme, and Institute of Health Research, Chulalongkom University. We also thank Richard Fawcett for technical assistanceChulalongkorn University. Biology Department. Bangkok, Thailand.University of Edinburgh Scotland. Genetics Department. South Bridge, Edinburgh, Reino Unido.University of Edinburgh Scotland. Genetics Department. South Bridge, Edinburgh, Reino UnidoUniversity of Edinburgh. Department of Zoology. South Bridge, Edinburgh, Reino Unido.Ministério da Saúde. Fundação Serviços de Saúde Pública. Instituto Evandro Chagas. Belém, PA, Brasil.University of Edinburgh. Genetics Department. South Bridge, Edinburgh, Reino Unido.University of Edinburgh. Genetics Department. South Bridge, Edinburgh, Reino Unido.Clones of an isolate of Plasmodium falciparum from Mae Sod (Thailand) were prepared by a dilution procedure. Some of the parasite cultures thus obtained have been typed for the following characters: (i) electrophoretic variants of three enzymes; (ii) susceptibility to chloroquine and pyrimethamine; (iii) antigen diversities recognized by ten strain-specific monoclonal antibodies; (iv) presence or absence of knobs on infected erythrocytes and (v) two-dimensional PAGE variants of seven proteins. Amongst the clones there was variation involving each of these five characters. At least seven different types of clones were found in ten cultures produced by dilution. The amount of phenotypic variation within a single isolate has thus been shown to be surprisingly great. Variations in drug susceptibility and antigens are considered to be particularly important in view of their relevance to anti-malarial treatments