Course of Plasmodium yoelii 17X infection following Py RMP immunization. Animals (n = 5) were immunized three times with the Py RMP preparation plus Quil A adjuvant. A separate group of animals received Quil A alone. Both groups were challenged with 1x105P. yoelii 17X iRBCs intraperitoneally. Parasitaemia was monitored in thin tail-blood smears stained with Giemsa at various time points post-infection. ‘#d’ indicates the number of animals at each time point that were sacrificed due to high parasitaemia and/or significant anemia.