Fig 9.

M. leprae recombinant Hlp and HBHA mediate the mycobacterial attachment to airway epithelial cells. (A and B) Fluorescent beads coated with Hlp (A), with HBHA (B), or with BSA (negative control) were incubated with RPMI 2650 and A549 cells for 1 h at 37°C. Cells were then washed and fixed. The numbers of beads associated with these cells were counted in a fluorescence microscope in a set of 300 cells using a magnification of ×400. (C) Fluorescent beads coated with Hlp, HBHA, or BSA were incubated simultaneously with A549 cells for 1 h at 37°C. (D) M. smegmatis (MS) was pretreated or not with Hlp (MS+Hlp) or HBHA (MS+HBHA), and an ELISA was performed with anti-Hlp or anti-HBHA, respectively, in order to monitor the binding of these proteins to the bacterial surface. (E) MS and Hlp or MS and HBHA were used to infect epithelial cells for 2 h at 37°C. Internalized bacteria were released with lysis buffer for CFU counting. The data represent the mean values ± SD of the results of at least three experiments performed in duplicate. *, P < 0.05; **, P < 0.01.