AK15 (A) and its isomer AK15-6 (B) were directly bound to M. tuberculosis H37Ra cells.
M. tuberculosis H37Ra cells were washed twice with PBS and exposed to FITC-labeled AK15 or AK15-6 (1 μg/ml) at 37 °C. PBS and FITC-labeled sAK15 (scrambled AK15) were used as control, respectively. After incubation for 5 min, M. tuberculosis H37Ra cells were washed twice with PBS, assayed on a FACSCalibur flow cytometer, and analyzed by Cell Quest software (BD Immunocytometry). **, p < 0.01. Error bars, S.E.