BACKGROUND: Regulatory T cells (Treg) are enriched in human colorectal cancer (CRC) where they suppress anti-tumour immunity. The chemokine receptor CCR5 has been implicated in the recruitment of Treg from blood into CRC and tumour growth is delayed in CCR5-/- mice, associated with reduced tumour Treg infiltration. METHODS: Tissue and blood samples were obtained from patients undergoing resection of CRC. Tumour-infiltrating lymphocytes were phenotyped for chemokine receptors using flow cytometry. The presence of tissue chemokines was assessed. Standard chemotaxis and suppression assays were performed and the effects of CCR5 blockade were tested in murine tumour models. RESULTS: Functional CCR5 was highly expressed by human CRC infiltrating Treg and CCR5(high) Treg were more suppressive than their CCR5(low) Treg counterparts. Human CRC-Treg were more proliferative and activated than other T cells suggesting that local proliferation could provide an alternative explanation for the observed tumour Treg enrichment. Pharmacological inhibition of CCR5 failed to reduce tumour Treg infiltration in murine tumour models although it did result in delayed tumour growth. CONCLUSIONS: CCR5 inhibition does not mediate anti-tumour effects as a consequence of inhibiting Treg recruitment. Other mechanisms must be found to explain this effect. This has important implications for anti-CCR5 therapy in CRC.
Antineoplastic Agents/pharmacology , CCR5 Receptor Antagonists/pharmacology , Colorectal Neoplasms/immunology , Cyclohexanes/pharmacology , T-Lymphocytes, Regulatory/immunology , Triazoles/pharmacology , Animals , Cell Line, Tumor , Cell Proliferation , Chemokine CCL4/metabolism , Chemotaxis, Leukocyte , Colorectal Neoplasms/drug therapy , Drug Screening Assays, Antitumor , Female , Humans , Maraviroc , Melanoma, Experimental/drug therapy , Melanoma, Experimental/immunology , Mice, Inbred BALB C , Neoplasm Transplantation , Receptors, CCR5/metabolism , T-Lymphocytes, Regulatory/metabolism
The hepatic sinusoids are lined by a unique population of hepatic sinusoidal endothelial cells (HSEC), which is one of the first hepatic cell populations to come into contact with blood components. However, HSEC are not simply barrier cells that restrict the access of blood-borne compounds to the parenchyma. They are functionally specialised endothelial cells that have complex roles, including not only receptor-mediated clearance of endotoxin, bacteria and other compounds, but also the regulation of inflammation, leukocyte recruitment and host immune responses to pathogens. Thus understanding the differentiation and function of HSEC is critical for the elucidation of liver biology and pathophysiology. This article reviews methods for isolating and studying human hepatic endothelial cell populations using in vitro models. We also discuss the expression and functions of phenotypic markers, such as the presence of fenestrations and expression of VAP-1, Stabilin-1, L-SIGN, which can be used to identify sinusoidal endothelium and to permit discrimination from vascular and lymphatic endothelial cells.
Amine Oxidase (Copper-Containing)/metabolism , Cell Adhesion Molecules, Neuronal/metabolism , Cell Adhesion Molecules/metabolism , Endothelial Cells/metabolism , Lectins, C-Type/metabolism , Liver/cytology , Liver/metabolism , Receptors, Cell Surface/metabolism , Receptors, Lymphocyte Homing/metabolism , Amine Oxidase (Copper-Containing)/genetics , Biomarkers/metabolism , Cell Adhesion Molecules/genetics , Cell Adhesion Molecules, Neuronal/genetics , Cells, Cultured , Endothelium, Lymphatic/cytology , Endothelium, Vascular/cytology , Gene Expression Regulation/genetics , Humans , Lectins, C-Type/genetics , Liver/blood supply , Liver Circulation , Phenotype , Receptors, Cell Surface/genetics , Receptors, Lymphocyte Homing/genetics
Two media (mCP medium and Tryptose Sulphite Cycloserine (TSC) agar) were evaluated for recovery of Clostridium perfringens in environmental and part-treated drinking water. For laboratory strains of Clostridium, mCP was more selective and specific for Cl. perfringens than TSC, but was markedly less efficient for the enumeration of both vegetative cells and spores. For samples of river water and part-treated drinking water, TSC recovered significantly greater numbers of Cl. perfringens than mCP. In contrast to previous reports, there was a significant number of false presumptive positive and negative isolates on mCP. TSC is a more suitable medium for the routine monitoring of water supplies for the presence of Cl. perfringens.
Clostridium perfringens/isolation & purification , Colony Count, Microbial , Water Microbiology , Culture Media , Filtration , Fresh Water , Water Supply
