Figure 2

Cloning and expression of the selected midgut proteins and their interaction with P. falciparum-infected cell lysates by ELISA assays. In total, sixty-one genes were expressed at the detected level. (A) Candidate gene IDs. The access number is AGAP(ID)-PA. (B) Heterologous expression of the midgut genes with a baculovirus expression system. The color intensity highlights a different expression level for each gene. The concentration of each expressed recombinant protein in each well in panel (B) corresponds to the genes at the same position in panel A. (C) P. falciparum-infected cell lysate was used to coat ELISA plates. The same amount of insect-expressed proteins was added to analyze their interaction with the lysate by standard ELISA. A₄₀₅ values were measured. The signals in panel C correspond to proteins at the same positions in panel A, plus a negative control (heat-inactivated FREP1) at the well of F8. The intensity of the binding signal was represented by the corresponding color: the dark brown color indicated no binding signal was detected, and the yellow color indicated the most substantial binding signal. The binding threshold was that A₄₀₅ of the candidate protein was ≥ threefold over the negative control (heat-inactivated FREP1).