We report the enrichment of and immune responses mediated by genes expressed by Mycobacterium tuberculosis inside macrophages as a function of time. Results indicate that M. tuberculosis expresses different genes at different times postinfection. Genes expressed early (day 1) following infection enhance M. tuberculosis-mediated activation of dendritic cells (DCs), whereas genes expressed later (day 5) in the infection prevent DC activation. However, all genes downmodulated MHC class I and II expression on infected macrophages, thus compromising their ability to interact with Ag-specific T cells. Day-1 and -5 genes downmodulated proinflammatory cytokine production from DCs, thus impairing signal 3 during DC–T cell cognate interactions. Consequently, T cells activated by Ag-experienced DCs secreted low levels of IFN-γ and IL-17 but maintained high IL-10 secretion, thus inducing suppressor responses. Further characterization revealed that day-1 and -5 genes increased TLR2-induced expression of suppressors of cytokine signaling 1 from DCs and downmodulated IL-12 expression. In addition, day-1 and -5 genes prevented the generation of reactive oxygen species in DCs. In contrast, although day-5 genes increased TLR2-mediated suppressors of cytokine signaling 1 expression in macrophages, day-1 genes downmodulated the expression of inducible NO synthase 2. Similar downregulation of immune responses was observed upon exogenous stimulation with day-1 or -5 Ags. Finally, day-1 and -5 genes promoted enhanced survival of M. tuberculosis inside DCs and macrophages. These results indicate that M. tuberculosis genes, expressed inside infected macrophages as a function of time, collectively suppress protective immune responses by using multiple and complementary mechanisms.

BackgroundDendritic cells (DCs) play major roles in mediating immune responses to mycobacteria. A crucial aspect of this is the priming of T cells via chemokines and cytokines. In this study we investigated the roles of chemokines RANTES and IP-10 in regulating protective responses from Mycobacterium tuberculosis (M. tb) 10 kDa Culture Filtrate Protein-10 (CFP-10) differentiated DCs (CFP10-DCs).Methods and FindingsInfection of CFP10-DCs with mycobacteria down-modulated RANTES and IP-10 levels. Pathway specific microarray analyses showed that in addition to RANTES and IP-10, mycobacteria infected CFP10-DCs showed reduced expression of many Th1 promoting chemokines and chemokine receptors. Importantly, T cells co-cultured with RANTES and IP-10 conditioned CFP10-DCs mediated killing of mycobacteria from infected macrophages. Similarly, T cells recruited by RANTES and IP-10 conditioned CFP10-DCs mediated significant killing of mycobacteria from infected macrophages. IFN-gamma treatment of CFP10-DCs restored RANTES and IP-10 levels and T cells activated by these DCs mediated significant killing of virulent M. tb inside macrophages. Adoptive transfer of either RANTES and IP-10 or IL-12 and IFN-gamma conditioned CFP10-DCs cleared an established M. tb infection in mice. The extent of clearance was similar to that obtained with drug treatment.ConclusionsThese results indicate that chemokine and cytokine secretion by DCs differentiated by M. tb antigens such as CFP-10 play major roles in regulating protective immune responses at sites of infection.

Kal-1 is a polyherbal decoction of seven different natural ingredients, traditionally used in controlling sugar levels, inflammatory conditions particularly regulating metabolic and immunoinflammatory balance which are the major factors involved in obesity and related diseases. In the present study, we aimed to investigate the effect of Kal-1 (an abbreviation derived from the procuring source) on diet-induced obesity and type II diabetes using C57BL/6J mice as a model. The present study was performed with two experimental groups involving obese and prediabetic mice as study animals. In one, the mice were fed on high-fat with increased sucrose diet, and different amounts (5, 20, and 75 μL) of Kal-1 were administered with monitoring of disease progression over a period of 21 weeks whereas in the second group the mice were first put on the same diet for 21 weeks and then treated with the same amounts of Kal-1. A significant reduction in body weight, fat pads, fasting blood glucose levels, insulin levels, biochemical parameters, immunological parameters, and an array of pro- and anticytokines was observed in obese and diabetic mice plus Kal-1 than control (lean) mice fed on normal diet. In conclusion, Kal-1 has immunomodulatory potential for diet-induced obesity and associated metabolic disorders.

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Obesity is a metabolic state associated with excess of positive energy balance. While adipose tissues are considered the major contributor for complications associated with obesity, they influence a variety of tissues and inflict significant metabolic and inflammatory alterations. Unfortunately, the communication network between different cell-types responsible for such systemic alterations has been largely unexplored. Here we study the inter-tissue crosstalk during progression and cure of obesity using multi-tissue gene expression data generated through microarray analysis. We used gene expression data sets from 10 different tissues from mice fed on high-fat-high-sugar diet (HFHSD) at various stages of disease development and applied a novel analysis algorithm to deduce the tissue crosstalk. We unravel a comprehensive network of inter-tissue crosstalk that emerges during progression of obesity leading to inflammation and insulin resistance. Many of the crosstalk involved interactions between well-known modulators of obesity and associated pathology like inflammation. We then used similar datasets from mice that in addition to HFHSD were also administered with a herbal concoction known to circumvent the effects of HFHSD in the diet induced model of obesity in mice. We propose, the analysis presented here could be applied to understand systemic details of several chronic diseases.