CD4+ T cells play a central role in the development of inflammatory bowel disease (IBD) via high-level production of effector cytokines such as IFN-γ and TNF-α. To better characterize the colitogenic CD4+ T cells, we examined their expression of CXCR6, a chemokine receptor that is expressed by T cells upon activation and is upregulated in several inflammatory diseases. We found that 80% of colonic lamina propria CD4+ T cells expressed CXCR6 in the CD45RBhigh T cell-transferred colitis model. CXCR6 expression was similarly upregulated in inflamed mucosa of patients with Crohn’s disease. Although surface marker analysis demonstrated that both CXCR6+ and CXCR6− CD4+ T-cell subsets consist of the cells with effector and effector-memory cells, the more cells in the CXCR6+ subset produced IFN-γ and TNF-α compared to CXCR6− subset, and only the CXCR6+ subset produced IL-17A. Nevertheless, adoptive retransfer of lamina propria CXCR6+ T cells into Rag1
−/− recipients failed to induce the disease due to limited expansion of the transferred cells. By contrast, retransfer of CXCR6− cells evoked colitis similar to that observed in CD4+CD45RBhigh T cell-transferred mice, and resulted in their conversion into CXCR6+ cells. Collectively, these observations suggest that the CXCR6+CD4+ T-cell subset consists of terminally differentiated effector cells that serve as the major source of effector cytokines in the inflamed tissue, whereas CXCR6−CD4+ T-cell subset serves as a colitogenic memory compartment that retains the ability to proliferate and differentiate into CXCR6+CD4+ T cells.
Forty-one types of crude oils were divided into the following six groups, based on the analysis of the homologous series of hopanes of 18R-22,29,30-trisnorneohopane (1), 17R-22,29,30-trisnorhopane (2), 17R-21β(H)-norhopane (3), oleananes (4), and 17R-21β(H)-hopane (5) as biomarkers by GC-MASS, in combination with the inductively coupled plasma-atomic emission spectroscopy (ICP-AES) measurement of nickel and vanadium and X-ray fluorescence spectroscopy (XFS) of sulfur: (a) northern Middle East; (b) eastern Middle East; (c) southern Middle East; (d) Borneo Island, Malaysia, and Vietnam; (e) Sumatra Island, China, Gabon, and Russia; and (f) Mexico crude oils. The relationship between the ratios of 4/5 and 3/5 classified the 41 crude oils into three groups of (d), (e), and (a-c) and (f), which was divided into (a) and (f), (b), and (c), based on the 3/5 and 1/2 ratios. Furthermore, the distribution of vanadium and nickel showed that the Middle East crude oils were subdivided into two groups: the southern parts and the northern parts. The individual Mexican crude oil was differentiated by the determination of the sulfur content of all the crude oils in combination with the vanadium and nickel contents. The crude oils were discriminated based on the hopane analysis in combination with the ICP-AES analysis of nickel and vanadium and XFS of sulfur. This combination method is superior for the identification of crude oils. Two analytical cases of spilled oils and heavy oils provided the discrimination into the individual oils based on the analysis of the hopane series.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.