trachomatis serovar GANT61 cost L2 One aspect of chlamydial Selleck Bucladesine infection is the gamma-interferon (IFN-γ) mediated induction of Indolamine-2, 3-dioxygenase (IDO), an enzyme catabolizing breakdown of tryptophan in culture media. The unavailability of this essential amino acid

can lead to chlamydial growth arrest termed as persistence [43]. The role of TNF-α mediated IDO induction in DCs [44] as well IFN-γ independent IDO activation in monocytic THP-1 cells have been reported earlier [45]. We considered that the level of IDO gene expression could be crucial in understanding the contrasting infection outcome by the chlamydia serovars in monocytes and monocyte-derived DCs. Hence the expression of IDO gene in chlamydiae-infected monocytes and DCs was detected over 3 days post infection. Monocytes, infected with serovars Ba and D expressed higher levels of IDO 1 day post infection (Figure 5). Contrastingly, IDO expression by serovar L2 infected monocytes was significantly down-regulated 1 day p.i compared to serovar D. On the other

days of infection the trend was similar but not significant. Figure 5 Indolamine 2, 3- dioxygenase (IDO) gene regulation in chlamydiae-infected monocytes and DCs. Monocytes and monocyte-derived DCs were infected with C. trachomatis serovars Ba, D and L2 (MOI-3) and mock control. IDO gene copy numbers was determined by isolating RNA at the indicated this website time points followed by real-time PCR as described in materials and methods. IDO fold change was normalized to 18S rRNA and determined by ddCt method with mock sample as reference gene. The mean of 3 independent experiments

is shown Adenosine triphosphate and each experiment is pool of 2 donors. ***P < 0.001, **P < 0.01, *P < 0.05. IDO expression was significantly up-regulated in DCs infected with serovar L2 (Figure 5) compared to serovars Ba and D. IDO expression declined throughout the infection course for all the servers, however maintaining a significant expression for serovar L2 infection. Attempts were made to enhance chlamydial recovery from infected monocytes and DCs by addition of Tryptophan, known to be depleted by IDO during chlamydial infection [34,46]. However the infected cultures supplemented with Tryptophan (200 μg/ml) when passaged on HeLa cells could not abrogate the growth arrest; chlamydial inclusions could not be recovered from serovar Ba and D cultures (data not shown). However, Serovar L2 could produce chlamydial inclusions irrespective of Tryptophan. Differential cytokine response induced in monocytes and DCs by chlamydial infection We investigated the role of cytokines in mediating contrasting infection outcome of chlamydia infection the monocytes and DCs. Supernatants were collected from monocyte and monocyte-derived DCs culture infected with C. trachomatis serovars Ba, D and L2 at 1 day p.i. and cytokine responses were assessed by Cytokine Bead Array.