Figure 2.

In vivo transfer of HI-IgGs together with HuPBMCs (A and B) or MNs (C and D) in P.f.-HuRBC-BXN mice. Individual parasitemia in two out of four mice injected sequentially with either 200 mg/kg of HI-IgGs at day 9, followed 6 d later by HuPBMCs (3 × 10⁷) (A) or the same in the reverse order on days 6 and 9, respectively (B). Arrows show treatment days. In mouse A (but not in mouse B) an additional dose of 100 mg/kg of HI-IgGs was added because of the longer delay between the two treatments and the fast catabolism of human IgGs. Two other mice undergoing the same protocol showed the same effect on the course of P. falciparum parasitemia. C and D show the individual parasitemia of two out of four mice undergoing the same protocol except that purified HuMNs were used at a rate of 3 × 10⁶ ntraperitoneally instead of total PBMCs, together with 200 mg/kg of HI-IgGs. In mouse D, only the initial IgG injection was of 200mg/kg and the further two were of 100 mg/kg. In two other mice, not shown in the figure, receiving IgG and/or MNs on days 10 and 15, or 16 and 22, respectively, the decrease of parasitemia occurred over 4 d after the first combined injection. Only mouse D showed a partial response to treatment. +, one or two parasites observed in thin blood smears; −, parasites no longer detectable in thin blood smears.