The transcription factor FOXP3 plays a key role in CD4 + CD25 + regulatory T cell function and represents a specific marker for these cells. Despite its strong association with regulatory T cell function, in humans little is known about the frequency of CD4 + CD25 + cells that express FOXP3 protein nor the distribution of these cells in vivo. Here we report the characterization of seven anti-FOXP3 monoclonal antibodies enabling the detection of endogenous human FOXP3 protein by flow cytometry and immunohistochemistry. Flow-cytometric analysis showed that FOXP3 was expressed by the majority of CD4

High macrophage infiltration into tumours often correlates with poor prognoses; in colorectal, stomach and skin cancers, however, the opposite is observed but the mechanisms behind this phenomenon remain unclear. Here, we sought to understand how tumour-associated macrophages (TAMs) in colorectal cancer execute tumoursuppressive roles. We found that TAMs in a colorectal cancer model were pro-inflammatory and inhibited the proliferation of tumour cells. TAMs also produced chemokines that attract T cells, stimulated proliferation of allogeneic T cells and activated type-1 T cells associated with anti-tumour immune responses. Using colorectal tumour tissues, we verified that TAMs in vivo were indeed pro-inflammatory. Furthermore, the number of tumour-infiltrating T cells correlated with the number of TAMs, suggesting that TAMs could attract T cells; and indeed, type-1 T cells were present in the tumour tissues. Patient clinical data suggested that TAMs exerted tumour-suppressive effects with the help of T cells. Hence, the tumour-suppressive mechanisms of TAMs in colorectal cancer involve the inhibition of tumour cell proliferation alongside the production of pro-inflammatory cytokines, chemokines and promoting type-1 T-cell responses. These new findings would contribute to the development of future cancer immunotherapies based on enhancing the tumour-suppressive properties of TAMs to boost anti-tumour immune responses. To elucidate the roles of TAMs, we first used an in vitro model known as the multi-cellular tumour spheroid (MCTS) model. This model has been proven to exhibit micro-environmental heterogeneity comparable to that of tumours in vivo, in terms of oxygen, nutrient, catabolite and metabolite gradients, resulting in sub-populations of proliferative and necrotic tumour cells typical of non-vascular tumour micro-regions [9,10]. Compared with using animal models, this MCTS model offers the advantages of studying the interactions between tumour cells and TAMs without confounding factors from other cell types, and in a 'human' microenvironment. In this study, we used colorectal cancer as a model to study the mechanisms underlying the tumour-suppressive effects of TAMs. We co-cultured primary human monocytes with human colorectal tumour cells for 8 days as MCTSs, during which time the monocytes would differentiate into TAMs. We performed global gene expression profiling to obtain an overview of the biological functions of TAMs, followed by validation with functional assays. Subsequently, we verified the in vitro findings with tumour tissues from colorectal cancer patients.The TAMs in the colorectal cancer model were pro-inflammatory and inhibited the proliferation of tumour cells. The TAMs also secreted chemokines that attract T cells and expressed surface molecules for antigen presentation and T-cell co-stimulation. In a mixed lymphocyte reaction (MLR) assay, the TAMs stimulated proliferation of allogeneic T cells and activated type-1 T cells, which are associated with anti-tumour immune responses [11]. To co...

Linkage and association studies implicate the human leucocyte antigen (HLA) region in genetic susceptibility to ulcerative colitis (UC). However, associations with specific variants have been inconsistent, even within defined ethnic groups. A genetic basis for the disease heterogeneity of UC may account for these discrepant findings from studies in unselected populations. Here, we examine the contribution of the HLA region to the clinical phenotype of UC. We studied 321 accurately phenotyped patients recruited from a single UK centre, with a median follow-up time of 15 years. Individuals were genotyped for 340 polymorphisms constructed into 25 gene-specific allelic haplotypes between HLA-A and Tapasin. Data were analysed with respect to age of onset, disease extent and severity. Strongest association with overall susceptibility was identified with HLA-DRB1 alleles replicating previous studies (DRB1*0103, DRB1*1502 and DRB1*0401). We report a novel association with homozygosity of a tumour necrosis factor (TNF) promoter haplotype (TNF-1031T, -863C, -857C, -380G, -308G and -238G) and distal disease extent that does not extend with time (distal vs total 40.9 vs 25.7%; RR = 2.0; 95% CI 1.23-3.24). We confirm the association of DRB1*0103 with total disease and/or disease requiring colectomy and further demonstrate that DRB1*0103 is associated with shorter time to surgery. Genes in the HLA play a role in modifying disease phenotype. Further studies are required to dissect how these genes functionally interact with each other and with environmental factors to determine clinical patterns of disease

Detailed knowledge of linkage disequilibrium (LD) is regarded as a prerequisite for population-based disease gene mapping. Variable patterns across the human genome are now recognized, both between regions and populations. Here, we demonstrate that LD may also vary within a genomic region in a haplotype-specific manner. In 864 Caucasian unrelated individuals, we describe haplotype-specific LD patterns across the human MHC by the construction of gene-specific allelic haplotypes at 25 loci between HLA-A and Tapasin. Strong and extensive LD is found across both common and rare haplotypes, suggesting that haplotype structure is influenced by factors other than genetic drift, including both selection and differential haplotype recombination. Knowledge of haplotype-specific LD in the HLA may explain the apparent discrepant data from previous studies of global LD, help delineate key areas in mapping HLA-associated diseases and, together with recombination data, provide valuable information about a population's demographic history and the selective pressures operating on it.

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