title: Immunization of man against falciparum and vivax malaria by use of attenuated sporozoites.
abstract: With strict adherence to ethical guidelines, a volunteer was immunized against sporozoites of Plasmodium falciparum and P. vivax, the antigen consisting of attenuated sporozoites of each species inoculated through bites of mosquitoes X-irradiated at a minimum dosage of 15,000 rads. On one occasion this dosage did not render all P. vivax sporozoites noninfective. Species specificity of antigen and antibody was demonstrated, but within each species a wide geographical diversity of strains proved interchangeably antigenic and susceptible to the antibody. Once immunized, the volunteer was protected for not more than 3 months and 6 months, respectively, from infective P. falciparum and P. vivax sporozoites, the duration of protection being reflected by a positive species-specific circumsporozoite reaction. Studies in this volunteer, and in two others immunized with P. falciparum sporozoites, did not reveal any increase in serum levels of immunoglobulins G and M.
mesh_terms: D000852:Anopheles / Q000469:parasitology / Q000528:radiation effects; D016782:Apicomplexa / Q000276:immunology / Q000472:pathogenicity* / Q000528:radiation effects; D006801:Humans; D007114:Immunization / Q000379:methods*; D007136:Immunoglobulins / Q000032:analysis; D008288:Malaria / Q000276:immunology / Q000517:prevention & control* / Q000635:transmission; D008297:Male; D008875:Middle Aged; D010963:Plasmodium falciparum / Q000187:drug effects / Q000276:immunology / Q000472:pathogenicity*; D010966:Plasmodium vivax / Q000187:drug effects / Q000276:immunology / Q000472:pathogenicity*
chemical_list: D007136:Immunoglobulins