FIG. 6.

(A) Dialysis of serum samples effectively removes antimalarial drugs added to serum. Quinine in different concentrations was added to serum from a nonexposed Australian donor. The serum was dialyzed and used in a growth inhibition assay performed over one cycle of replication with measurement of parasitemia by flow cytometry. Untr ser, untreated serum; Q, quinine; Dial, dialyzed. (B) Comparison of dialyzed serum samples, Ig purified from the same sera, and untreated serum tested for growth inhibitory activity using an assay performed over two cycles of parasite replication. S1 and S2, sera from nonexposed Australian donors; A to K, sera from adult residents of PNG. (C) Different dilutions of serum or plasma were tested in a growth inhibition assay performed over two life cycles. AMA, rabbit polyclonal antibody against AMA1; PNG, plasma from an adult from PNG; Ser, serum from a nonimmune Swedish donor. All samples were used in duplicate with the 3D7 parasite line, and error bars indicate ranges.