Figure 2.

Determination in-vitro of the intracellular proliferative activity of Beijing strains and cytokine production in infected alveolar macrophages. A) Alveolar macrophages cell line MH-S were infected n = 3 with the indicated strain (MOI 5/1), and at different time points infected cells of the three replicates were collected and prepared to determine bacterial viability by colony forming units quantification. BL showed significant higher proliferative activity after 3 and 4 days of incubation. B-F) The supernatants were collected in pools from the infected macrophages after each day PI, and the indicated cytokines were measured by ELISA (asterisk indicate statistical significance * = P < 0.05, ** = P < 0.005, *** = P < 0.0005, **** = P < 0.0001