Table 3.
Evaluation of in vitro antiparasitic activities of CDC/NII MAL VAC-1-elicited antibodies [growth inhibition of the blood-stage parasite in the presence of monocytes (ADCI)]
| Antibodies | Antibody
concentration, ug/ml
|
||||||||
|---|---|---|---|---|---|---|---|---|---|
| 50
|
25
|
12.5
|
|||||||
| Parasitemia
|
Parasitemia
|
Parasitemia
|
|||||||
| No monocyte | Monocyte | Inhibition, % | No monocyte | Monocyte | Inhibition, % | No monocyte | Monocyte | Inhibition, % | |
| Preimmune | 2.56 (0.07) | 1.64 (0.1) | 0 | 3.39 (0.09) | 2.25 (0.065) | 0 | 3.75 (0.13) | 2.48 (0.105) | 0 |
| Freund | 3.33 (0.07) | 0.65 (0.025) | 70 | 3.49 (0.04) | 1.77 (0.125) | 23 | 3.56 (0.025) | 2.19 (0.095) | 7 |
| Copolymer | 2.85 (0.09) | 0.50 (0.025) | 73 | 3.10 (0.12) | 1.43 (0.11) | 30 | 3.46 (0.01) | 1.68 (0.06) | 26 |
| Alum | 2.97 (0.14) | 0.63 (0.11) | 67 | 3.33 (0.05) | 1.10 (0.05) | 50 | 3.65 (0.125) | 1.40 (0.17) | 42 |
| Positive control | 3.17 (0.1) | 1.17 (0.035) | 29 | ND | ND | ||||
Parasitemia given as mean numbers of parasitemias in duplicate cell culture with SD given in parenthesis. Inhibition expressed as relative to preimmune control culture (0%) and taking into account the possible inhibition induced by monocyte and antibody alone, which was calculated as follows: 100 × [(1 − [(mean parasitemia with test IgG and monocyte/mean parasitemia with test IgG and without monocyte)/(mean parasitemia with control IgG and monocyte/mean parasitemia with control IgG and without monocyte)])]. Preimmune, antibodies purified from preimmune rabbits used as negative control; Freund, antibodies purified from rabbit receiving Freund’s as adjuvant; Copolymer, antibodies purified from rabbit receiving nonionic block copolymer P1005 as adjuvant; Alum, antibodies purified from rabbit receiving aluminum hydroxide as adjuvant. For positive control, mAb against sporozoites (NFS1) was used. ND, not done.