TABLE 1.

Course of infection in A. vociferans monkeys challenged with P. falciparum parasites

Vaccine group and monkey	ELISA titera to:		Days to:		% Parasitemia		Outcomed
	AMA1	MSP142	Patencyb	Treatmentc	Peak	At treatment
Pvs25H
T1119	206	982	5	11	6.20	6.20	Virulent
T1172	63	4,160	5	11	6.25	6.25	Virulent
T907	7,450	22,750	6	11	6.50	6.50	Virulent
T978	75	12,280	6	11	20.15	20.15	Virulent
T1136	11,020	42,800	7	14	7.55	7.55	Virulent
Meane	603	8,665	6	12 (Δ = 7)	9	9
Naïve
T1146	—	—	4	11	25.05	25.05	Virulent
T1091	—	—	5	9	9.05	9.05	Virulent
T1169	—	—	5	11	17.1	17.1	Virulent
T960	—	—	7	11	8.05	8.05	Virulent
Mean	—	—	5	11 (Δ = 7)	15	15
MSP142
T1139	149	135	7	15	3.35	3.35	Anemic (V)
T1115	51	136	6	15	4.60	4.60	Virulent
T891	16	73	6	14	10.05	10.05	Virulent
T1096	37	109	5	28	0.07	0.00	Self-cured
Mean	52	96,438	6	18 (Δ = 13)	5	5
AMA1
T979	311,200	168	—	28	0.00	0.00	Subpatent (Dp)
T1089	152,600	1,975	10	18	0.60	0.60	Anemic (Dp)
T1185	336,800	419	—	28	0.00	0.00	Subpatent (Dp)
T1152	87,200	7,000	6	12	7.60	7.60	Virulent
T1102	328,400	11,130	9	21	5.10	5.10	Virulent (Dp)
T1112	82,600	1,000	22	36	0.55f	0.35	Controlled (Dp)
Mean	183,222	1,487	17	23 (Δ = 7)	2	2
AMA1 + MSP142
T1138	38,600	77,500	7	14	6.80	6.80	Virulent
T964	161,400	87,100	24	33	0.65f	4.0	Controlled (Dp)
T1173	13,850	199,100	10	20	0.16	0.16	Anemic (Dp, C)
T1188	39,000	146,600	7	20	0.02	0.00	Anemic (Sc)
T914	72,200	164,400	11	20	5.70	5.70	Virulent (Dp)
T1155	260,400	90,500	—	28	0.00	0.00	Subpatent (Dp)
T986	110,975	188,700	—	14	5.60	5.60	Virulent
Mean	61,567	108,375	13	21 (Δ = 9)	3	3

^aExpressed in arbitrary antibody units, calculated by reference to a standard Aotus serum against the plate antigen. A serum dilution of the reciprocal of the antibody units reported would give an approximate absorbance at 405 nm of 1.0. —, not measured.

^bMonkeys T979, T1185, and T1155 were subpatent (parasitemia, <0.01%) for the 28-day course of the challenge.

^cIf not already treated, all monkeys were treated on day 28, except T1112 and T964, which were subpatent for 22 and 24 days, respectively, so treatment was deferred in order to monitor the course of their parasitemia. Shown also are the numbers of days between treatment and patency (Δ).

^dDescribes course of infection. Virulent, a sharply rising, uncontrolled parasitemia requiring treatment (parasitemia, >5%); subpatent, no parasites observed per 10,000 RBCs over the course of the challenge; self-cured, parasites cleared by the animal without intervention; controlled, parasite growth controlled to low levels for the 28 days of the study; anemic, monkey required treatment for anemia (hematocrit, <25%). At the time of treatment for anemia, the course of the parasitemia could be virulent (V), controlled (C), or self-cured (Sc). The course of the infection was also modified in some animals by a delay to patency (Dp), where the animal became patent after all control animals had become patent (>7 days).

^eShown are geometric mean ELISA titers and arithmetic means for each of the other columns, including only data from the 28 days of challenge. Thus for this purpose, T979, T1185, and T1155 are considered to have 28 days to patency; T1112 and T964 are considered to have 28 days to treatment, with peak parasitemias and parasitemias at day 28 of 0.55 and 0.65, respectively.

^fShown is the peak parasitemia within the 28-day challenge period. Monkeys T1112 and T964 were monitored for an additional period, when they eventually had peak parasitemias of 0.75% (T1112) and 4.0% (T964).