Figure 6.

Effect of antibodies targeting Hsp70A1A and PfPHB2 on parasite-RBC binding and merozoite invasion

(A) IFA images probed using anti-PfPHB2 antibody depicting no binding of recombinant PfPHB2 to RBC surface in presence of anti-PfPHB2 antibody (i) and anti-Hsp70A1A monoclonal antibody (ii). (A iii) IFA images showing direct binding of PfPHB2 to RBCs in absence of any antibody (positive control). DIC: differential interference contrast image, Alexa 488: mouse anti-PfPHB2 (green); merge: overlay of PfPHB2 with DIC (Scale bar: 2 μm). (A iv) Intensity of PfPHB2 staining in RBCs under each condition is shown as an intensity graph (p < 0.0001∗∗∗∗).

(B i) Graph representing percentage invasion inhibition of malaria parasite into normal erythrocytes in the presence of PfPHB1 and PfPHB2 antisera at a dilution of 1:5 and 1:10. Data represent the mean ± SD (n = 3) (p values ≤0.05∗). (B ii) Giemsa-stained images of Pf3D7 after treatment with PfPHB1 and PfPHB2 antisera (1:5, 1:10; scale bar: 5 μm) and PfPHB2 preimmune sera.

(C i) Graph representing percentage invasion inhibition of Pf3D7 into normal RBCs in the presence of anti-Hsp70A1A monoclonal antibody (0.25 mg/mL, 0.5 mg/mL, 0.75 mg/mL and 1 mg/mL). The experiment was done in triplicate, and the results were shown as mean values ±SD. (p-values ≤0.05∗) (C ii) Giemsa-stained images of Pf3D7 treated with and without anti-Hsp70A1A monoclonal antibodies. Scale bar: 5 μm.