Acute virulent infection with Plasmodium chabaudi does not impair the generation of a protective immune response

Publisher Website
Google Scholar
Abstract
We have investigated whether a prtoective immune response occurred in mice infected with a virulent cloned strain of P chabaudi. Animals inoculated intraveneously with 107 parasitized erythrocytes (PE) showed an exponentially increasing parasitaemia and died by day 6 of the infection, presenting pronounced anaemia. Smaller inocula produced a longer pre-patent period but did not change the lethal course of infection, since mice infected with 100 parasites died on day 12. When anaemia was compensated for by red blood cell (RBC) transfusion, infected mice recovered and thereafter exhibited a strong immunity, comparable to that of mice immunized by a drug-controlled infection. The immune response was P. chabaudi specific, as the mice were fully susceptible to a challenge by P. yoelii. Three transfusions of 5 .times. 109 RBC per mouse at 2-day intervals were necessary before all the animals were able to control the infection. Transfusion of a larger number of RBC resulted in a lower anaemia and a delay in reticulocytaemia but, paradoxically, the expression of the immune response was delayed. Three transfusions of 1.2 .times. 1010 RBC enabled three out of eight mice to survive the infection, while six transfusions enabled all the mice to survive. The data suggest that parasitized immature RBC could play and important role in triggering the protective immune response.