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Antigen (Ag)-presenting cells (APC) instruct CD4+ helper T (Th) cell responses, but it is unclear whether different APC subsets contribute uniquely in determining Th differentiation in pathogen-specific settings. Here, we use skin-relevant, fluorescently-labeled bacterial, helminth or fungal pathogens to track and characterize the APC populations that drive Th responses in vivo. All pathogens are taken up by a population of IRF4+ dermal migratory dendritic cells (migDC2) that similarly upregulate surface co-stimulatory molecules but express pathogen-specific cytokine and chemokine transcripts. Depletion of migDC2 reduces the amount of Ag in lymph node and the development of IFNγ, IL-4 and IL-17A responses without gain of other cytokine responses. Ag+ monocytes are an essential source of IL-12 for both innate and adaptive IFNγ production, and inhibit follicular Th cell development. Our results thus suggest that Th cell differentiation does not require specialized APC subsets, but is driven by inducible and pathogen-specific transcriptional programs in Ag+ migDC2 and monocytes.

Healing is delayed in limb wounds relative to body wounds of horses, partly because of sustained inflammation and inefficient angiogenesis. In laboratory animals, proteins derived from orf virus modulate these processes and enhance healing. We aimed to compare immune cell trafficking and the inflammatory, vascular, and epidermal responses in body and limb wounds of horses and then to investigate the impact of orf virus interleukin-10 and vascular endothelial growth factor-E on these processes. Standardized excisional wounds were created on the body and forelimb of horses and their progression monitored macroscopically until healed. Tissue samples were harvested to measure the expression of genes regulating inflammation and repair (quantitative polymerase chain reaction) and to observe epithelialization (histology), innate immune cell infiltration, and angiogenesis (immunofluorescence). Delayed healing of limb wounds was characterized by intensified and extended pro-inflammatory signaling and exacerbated innate immune response, concomitant with the absence of anti-inflammatory eIL-10. Blood vessels were initially more permeable and then matured belatedly, concomitant with retarded production of angiogenic factors. Epithelial coverage was achieved belatedly in limb wounds. Viral proteins were administered to wounds of one body and one limb site/horse at days 1-3, while wounds at matching sites served as controls. Treatment dampened pro-inflammatory gene expression and the innate immune response in all wounds. It also improved angiogenic gene expression, but primarily in body wounds, where it altered blood vessel density and myofibroblast persistence. Moreover, the viral proteins increased epithelialization of all wounds. The short-term viral protein therapy did not, however, improve the healing rate of wounds in either location, likely due to suboptimal dosing. In conclusion, we have further detailed the processes contributing to protracted healing in limb wounds of horses and shown that short-term administration of viral proteins exerts several promising though transient effects that, if optimized, may positively influence healing.

This study shows that VEGF-E and ovIL-10 are active on equine dermal cells and exert anti-inflammatory and anti-fibrotic effects that may enhance skin wound healing in horses.

Background Mouse models have been extremely valuable in identifying the fundamental mechanisms of airway inflammation that underlie human allergic asthma. Several models are commonly used, employing different methods and routes of sensitisation, and allergens of varying clinical relevance. Although all models elicit similar hallmarks of allergic airway inflammation, including airway eosinophilia, goblet cell hyperplasia and cellular infiltration in lung, it is not established whether they do so by involving the same mechanisms. Results We compared the impact of inactivation of various innate or adaptive immune genes, as well as sex, in different models of allergic airway inflammation in mice of C57BL/6 background. Chicken ovalbumin (OVA) and house dust mite (HDM) were used as allergens in settings of single or multiple intranasal (i.n.) challenges, after sensitisation in adjuvant or in adjuvant-free conditions. Eosinophil numbers in the broncho-alveolar lavage and lung histopathology were assessed in each model. We found that Major Histocompatibility Complex Class II (MHCII) deficiency and lack of conventional CD4+ T cells had the most profound effect, essentially ablating airway eosinophilia and goblet cell hyperplasia in all models. In contrast, Thymic stromal lymphopoietin receptor (TSLPR) deficiency greatly reduced eosinophilia but had a variable effect on goblet cells. CD1d deficiency and lack of Natural Killer T (NKT) cells moderately impaired inflammation in OVA models but not HDM, whereas sex affected the response to HDM but not OVA. Lastly, defective Toll-like receptor (TLR)4 expression had only a relatively modest overall impact on inflammation. Conclusion All the models studied were comparably dependent on adaptive CD4+ T cell responses and TSLP. In contrast, sex, NKT cells and TLR4 appeared to play subtler and more variable roles that were dependent on the type of allergen and mode of immunization and challenge. These results are consistent with clinical data suggesting a key role of CD4+ T cells and TSLP in patients with allergic asthma. Electronic supplementary material The online version of this article (10.1186/s12865-019-0295-y) contains supplementary material, which is available to authorized users.

David A. eccles & franca Ronchese * colorectal cancer is a major contributor to death and disease worldwide. the Apc Min mouse is a widely used model of intestinal neoplasia, as it carries a mutation also found in human colorectal cancers. However, the method most commonly used to quantify tumour burden in these mice is manual adenoma counting, which is time consuming and poorly suited to standardization across different laboratories. We describe a method to produce suitable photographs of the small intestine of Apc Min mice, process them with an imageJ macro, FeatureCounter, which automatically locates image features potentially corresponding to adenomas, and a machine learning pipeline to identify and quantify them. Compared to a manual method, the specificity (or True Negative Rate, TNR) and sensitivity (or True Positive Rate, TPR) of this method in detecting adenomas are similarly high at about 80% and 87%, respectively. Importantly, total adenoma area measures derived from the automatically-called tumours were just as capable of distinguishing high-burden from low-burden mice as those established manually. overall, our strategy is quicker, helps control experimenter bias, and yields a greater wealth of information about each tumour, thus providing a convenient route to getting consistent and reliable results from a study. Human colorectal cancer is a major contributor to both disease and death in the Western world, with approximately 1.1 million cases diagnosed in 2018 1. Due to the massive impact of colorectal cancer worldwide, many animal models have been created to understand this disease and test potential treatments. Mutations in the Wingless/Int-1 (Wnt) pathway are commonplace in human colorectal cancer 2. The Adenomatous polyposis coli (APC) protein is part of the canonical Wnt pathway, which is strongly conserved across many species, including humans and mice. APC promotes the destruction of ß-catenin and prevents Wnt signalling. Interestingly, the Apc gene is mutated in over 80% of colorectal cancer cases, as well as in some breast cancers 3. One of the Apc mutations is particularly noteworthy, as it causes Familial Adenomatous Polyposis 4. This hereditary genetic disease causes thousands of polyps to form in the patient's colon, which will invariably lead to colorectal cancer if that patient is not screened and treated. The Apc Min mouse is a widely used model of spontaneously occurring intestinal tumours that closely model human Familial Adenomatous Polyposis 5. Apc Min mice have been highly valuable in demonstrating key mechanisms in colorectal cancer, for example, the importance of Vascular Endothelial Growth Factor in the initial growth of intestinal tumours 6 , the role of COX-2 in adenoma formation 7 , and the role of IL-33 in promoting tumorigenesis by modifying the tumour immune environment 8. Apc Min mice produce an inactive, truncated APC protein due to a mutation leading to a premature stop codon in the Apc gene 9. This functional loss in Apc Min mice favours aberrant cell growth and, ul...

The signals driving the adaptation of type-2 dendritic cells (DC2s) to diverse peripheral environments are not well understood. We show that the development of CD11blow migratory DC2s, a DC2 population unique to the dermis, requires STAT6- and KLF4-dependent IL-13 signaling, whereas DC2s in lung and small intestine are STAT6-independent. Dermal IL-13 is mostly derived from innate lymphoid cells expressing a resting ICOS+ KLRG1-ST2-phenotype. Analysis of public datasets indicates that human skin DC2s also express an IL-4/IL-13 gene signature compared to blood or spleen, suggesting a similar developmental pathway in mice and humans. In the absence of IL-13 signaling, dermal DC2s are stable in number but remain CD11bhi and show defective activation in response to allergen with diminished ability to support IL-4+ GATA3+ Th development, whereas anti-fungal IL-17+ RORγt+ responses are increased. Thus, steady-state IL-13 fosters a non-inflammatory and pro-allergic environment in healthy skin via conditioning of local DC2s.

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