Fig. 1

Phosphate deprivation increases M. bovis/BCG phagocytosis. J774A.1 MOs (5 × 10⁵) were incubated with M. bovis/BCG bacilli labeled red with the PKH-26; nuclei were stained blue with DAPI. Immunofluorescence microscopy shows a marked difference in the degree of phagocytosis between bacilli grown with and without Pi (a, b). For FACS analysis gates considering the percent and the mean fluorescence index (MFI) were carried out (c, d). Dose-dependent phagocytosis that was significantly higher with Pi-deprived mycobacteria was observed (e, f). At a 1:20 MOI, 80.2% of MOs phagocytosed bacilli cultured without Pi while the percent phagocytosis of bacilli cultured with Pi was 38.7; p < 0.05; unpaired t Student’s test. Results of 5 independent experiments are shown