Prospects for the development of malaria vaccines

The collection of epidemiological data on malaria in man dates from the time of the discovery of the human-pathogenic plasmodia, and, in retrospect, many of these observations can be seen to have an immunological connotation. This circumstantial evidence of the immunological phenomena in malaria was obtained during the first quarter of this century through the analysis of parasitological, clinical, and epidemiological data. The second quarter brought confirmation of the existence of a variety of immune phenomena in the naturally infected host, and the development of a number of animal models which proved to be useful in immunological studies. Also during that period the first successful attempts at inducing immune protection in experimental hosts were recorded. This work was considerably expanded during the 1970s and culminated in the evidence of sterilizing protective immunity against homologous challenge in human subjects immunized with irradiated sporozoites of Plasmodium falciparum and P. vivax. The development of immunodiagnostic methods, including serological techniques, made rapid progress during the same period. Recently, the application of the cell-fusion (hybridoma) technique to malaria has made it possible to produce pure, monoclonal antibodies, some of which have proved to be protective. These monoclonal antibodies should be useful in the isolation of pure, specific antigens and the use of gene cloning, and recombinant DNA techniques seems to offer realistic prospects of success in mass production. Development in this area has gathered momentum rapidly and the fact that specialized industries are now interested in the production of malaria vaccines is evidence enough that such vaccines have moved into the sphere of possibility.