Purpose: Anticancer T-cell responses can control tumors, but immunosuppressive mechanisms in vivo prevent their function. The role of regulatory T cells (Tregs) in metastatic colorectal cancer is unclear. We have previously shown depletion of Tregs enhances colorectal cancer-specific effector T-cell responses. Low-dose cyclophosphamide targets Tregs in animal models and some human studies; however, the effect of cyclophosphamide in metastatic colorectal cancer is unknown.Experimental Design: Fifty-five patients with metastatic colorectal cancer were enrolled in a phase I/II trial and randomly assigned to receive 2-week-long courses of low-dose (50 mg twice a day) cyclophosphamide or not. The absolute number, phenotype, and antitumor function of peripheral blood-derived lymphocyte subsets were monitored throughout treatment, as well as during 18-month follow-up.Results: Initially, cyclophosphamide reduced proliferation in all lymphocyte subsets; however, a rapid mobilization of effector T cells overcame this decrease, leading to increased absolute T-cell numbers. In contrast, a reduction in proportional and absolute Treg, B-cell, and NK-cell numbers occurred. The expansion and subsequent activation of effector T cells was focused on tumor-specific T cells, producing both granzyme B and IFNg. Cyclophosphamide-treated patients demonstrating the most enhanced IFNg þ tumor-specific T-cell responses exhibited a significant delay in tumor progression [HR ¼ 0.29; 95% confidence interval (CI), 0.12-0.69; P ¼ 0.0047), compared with nonresponders and no-treatment controls.Conclusions: Cyclophosphamide-induced Treg depletion is mirrored by a striking boost in antitumor immunity. This study provides the first direct evidence of the benefit of naturally primed T cells in patients with metastatic colorectal cancer. Our results also support the concept that nonmutated self-antigens may act as useful targets for immunotherapies.

Effective treatment of osteoarthritis (OA) remains a huge clinical challenge despite major research efforts. Different tissues and cell-types within the joint contribute to disease pathogenesis, and there is great heterogeneity between patients in terms of clinical features, genetic characteristics and responses to treatment. Inflammation and the most abundant immune cell type within the joint, macrophages, have now been recognised as possible players in disease development and progression. Here we discuss recent findings on the involvement of synovial inflammation and particularly the role of synovial macrophages in OA pathogenesis. Understanding macrophage involvement may hold the key for improved OA treatments.

SummaryCytotoxic CD8+ T lymphocytes play a critical role in the host response to infection by viruses. The ability to secrete cytotoxic chemicals and cytokines is considered pivotal for eliminating virus. Of equal importance is how effector CD8+ T cells home to virus-infected tissues. L-selectin has not been considered important for effector T cell homing, because levels are low on activated T cells. We report here that, although L-selectin expression is downregulated following T cell priming in lymph nodes, L-selectin is re-expressed on activated CD8+ T cells entering the bloodstream, and recruitment of activated CD8+ T cells from the bloodstream into virus-infected tissues is L-selectin dependent. Furthermore, L-selectin on effector CD8+ T cells confers protective immunity to two evolutionally distinct viruses, vaccinia and influenza, which infect mucosal and visceral organs, respectively. These results connect homing and a function of virus-specific CD8+ T cells to a single molecule, L-selectin.

Background The relationship between intestinal epithelial integrity and the development of intestinal disease is of increasing interest. A reduction in mucosal integrity has been associated with ulcerative colitis, Crohn’s disease and potentially could have links with colorectal cancer development. The Ussing chamber system can be utilised as a valuable tool for measuring gut integrity. Here we describe step-by-step methodology required to measure intestinal permeability of both mouse and human colonic tissue samples ex vivo, using the latest equipment and software. This system can be modified to accommodate other tissues. Methods An Ussing chamber was constructed and adapted to support both mouse and human tissue to measure intestinal permeability, using paracellular flux and electrical measurements. Two mouse models of intestinal inflammation (dextran sodium sulphate treatment and T regulatory cell depletion using C57BL/6-FoxP3 DTR mice) were used to validate the system along with human colonic biopsy samples. Results Distinct regional differences in permeability were consistently identified within mouse and healthy human colon. In particular, mice showed increased permeability in the mid colonic region. In humans the left colon is more permeable than the right. Furthermore, inflammatory conditions induced chemically or due to autoimmunity reduced intestinal integrity, validating the use of the system. Conclusions The Ussing chamber has been used for many years to measure barrier function. However, a clear and informative methods paper describing the setup of modern equipment and step-by-step procedure to measure mouse and human intestinal permeability isn’t available. The Ussing chamber system methodology we describe provides such detail to guide investigation of gut integrity. Electronic supplementary material The online version of this article (10.1186/s12876-019-1002-4) contains supplementary material, which is available to authorized users.