Experimental infection and protection against ... - TI Pharma

Safety and Immunogenicity of a Recombinant Plasmodium falciparum AMA1
Malaria vaccine Adjuvanted with Alhydrogel TM, Montanide ISA 720 or AS02
The effect of purified IgG antibodies on parasite invasion was evaluated with
two IgG concentrations (5 and 10 mg/mL, respectively) in triplicate using 96 well
flat-bottomed plates (Greiner) with synchronized cultures of P. falciparum
schizonts at a starting parasitemia of 0.2-0.4%, a haematocrit of 2.0% and a final
volume of 100 µL containing 10% control non-immune human serum, 20 µg /ml
gentamicin in RPMI 1640. After 40 to 42 hours, cultures were resuspended, and
50 µL was transferred into 200 µL ice-cold PBS. The cultures were then
centrifuged, the supernatant removed and the plates were frozen. Inhibition of
parasite growth was estimated using the pLDH assay as previously described
[14]. Parasite growth inhibition, reported as a percentage, was calculated as
follows: 100 - ((Odexperimental - Od background)/ (Odcontrol - Odbackground)
x 100). IgG purified from plasma before immunisation was used as a control, and
culture medium was used to measure the background Od.
Statistical methods
Safety analyses were based on intention to treat data selection (n=56). For
immunology assays, per protocol analyses were used (n=47). Between group
differences were calculated by one-way ANOVA, using post-hoc Bonferroni
when p