In this context, S. typhimurium induced the highest uptake by B cells. The level of internalisation of S. typhimurium was higher than that achieved with PMA, which is considered an efficient inducer of macropinocytosis [25]. Both of the mycobacteria induced a lower uptake; however, in contrast to Salmonella or PMA, selleck we did not observe any reduction in the fluorescence uptake throughout the experiment. The use of pharmacological inhibitors complements the study of endocytosis and aids in the elucidation of the endocytic processes that occur in different cells [26, 49, 50]. In this study,

we found that, during Salmonella or mycobacteria infections, the fluid-phase uptake was abolished by CD, WORT, and AMIL, confirms the involvement of the cytoskeleton during the infection, the participation of PI-3K, and the phenomenon of macropinocytosis as the process that is responsible for the bacterial internalisation. Interestingly, the M. tuberculosis and M. smegmatis culture supernatants (obtained during the log-phase growth of the bacteria) were able to induce the same Ixazomib mw level of fluid-phase uptake as the live bacteria. Furthermore, the supernatant fluid-phase uptake was inhibited by all of the inhibitors, which suggests that the soluble factors that are produced by these bacteria

are able to induce macropinocytosis and is consistent with previous studies that have suggested this phenomenon in other cell types [18, 19]. Different from other B-cell models [29, 43, 44], S. typhimurium was eliminated by the Raji B cells (Figure 1b), no replicating intracellular bacteria were observed in the Salmonella-containing vacuoles of these B cells, and no SIF structures were induced in the cells during the Salmonella productive infection [41, 42]. Instead, we observed (Figure 4f) non-replicating

bacteria, some of which were in the process of being destroyed, multilamellar bodies, and some late degradative Etofibrate autophagic vacuoles (LDAV) [51]; the presence of these structures suggests that autophagy was in progress, which could be partly responsible for the containment of the Salmonella growth [52], although this observation should be analysed in more detail. In contrast to the Raji B-cell line, the Ramos B-cell line can internalise only Salmonella that is bound to the specific anti-Salmonella antibody; thus, the BCR-mediated internalisation in these cells allowed Ag presentation, IgM anti-Salmonella production, and Salmonella intracellular survival [29]. B cells from early vertebrates, such as teleost fish, are able to internalise bacteria and exert microbicidal abilities [10]. In this study, Raji B cells, like the B cells from early vertebrates, were able to control S. typhimurium and M. smegmatis but not M.