title: [Experimental production of variants with lowered preference for polychromatophilic erythrocytes in Plasmodium yoelii (author's transl)].
abstract: After 25 massive passages of a Plasmodium yoelii-population (strain 17X) in the phase of high parasitization of mature erythrocytes, parasites with markedly lowered preference for immature erythrocytes could be isolated. Of 3 isolates in 3 independent experiments, one showed a distinctly lower preference than the other two. With very high infecting doses, the isolates caused in most mice high parasitization of mature erythrocytes and death. The original strain had been kept in mice by passage of a few parasites every 1--2 weeks for several months; on testing it exhibited a somewhat lower preference for immature erythrocytes and less polyparasitization of immature erythrocytes for a given multiplicity. Polyparasitization seemed to be unaltered in the 3 isolates. Antiserum against Plasmodium yoelii inhibited 2 tested isolates more than the modified original strain. These observations suggest that Plasmodium yoelii merozites may exist in several types differing in their relative affinity for mature erythrocytes, antibodies and parasitized immature erythrocytes. Different types should become predominant under different selective pressures. The different types are probably formed by mutations determining alterations in molecules of the merozoite surface.
mesh_terms: D000818:Animals; D004195:Disease Models, Animal; D004912:Erythrocytes / Q000469:parasitology*; D008288:Malaria / Q000469:parasitology*; D051379:Mice; D008815:Mice, Inbred Strains; D010961:Plasmodium / Q000472:pathogenicity / Q000502:physiology*
vernacular_title: Experimentelle Erzeugung von Plasmodium yoelii-Varianten mit verringerter Polychromenpräferenz.