Figure 5
From: Pneumococcal Pneumolysin Induces DNA Damage and Cell Cycle Arrest
Neutralizing oligomerization domain of pneumolysin prevents its genotoxicity.
(A) Hemolysis assay was performed to test the ability of anti-pneumolysin monoclonal antibody (mAb) to neutralize the lytic activity of 25 ng/ml pneumolysin against RBCs. Extent of hemoglobulin released during pneumolysin-mediated RBC lysis is expressed as percentage of total hemolysis during RBC treatment by lysis buffer. (B) Alveolar epithelial cells were exposed to pneumolysin for 12 h in the presence of anti-pneumolysin mAb. LDH assay was performed on the culture supernatant and expressed as percentage of total LDH released during lysis by 1% Triton X-100. Similarly, alveolar epithelial cells exposed to pneumolysin, in the presence of anti-pneumolysin mAb, were analyzed for (C) γH2AX at 12 h and (D) cell cycle arrest at 24 h and 48 h. (E) Alveolar epithelial cells were exposed to pneumococcal lysate for 7 h in the presence of anti-pneumolysin mAb. Representative images from three independent experiments showing prevention of DNA damage by mAb, with nuclei (blue) and γH2AX (red). Results show mean ± SEM for three independent experiments. *p < 0.05, unpaired Student’s t-test.
