The evolution of immune blockades in tumors limits successful antitumor immunity, but the mechanisms underlying this process are not fully understood. Depletion of regulatory T cells (Treg), a T-cell subset that dampens excessive inflammatory and autoreactive responses, can allow activation of tumor-specific T cells.

Balancing the generation of immune responses capable of controlling virus replication with those causing immunopathology is critical for the survival of the host and resolution of influenza-induced inflammation. Based on the capacity of interleukin-6 (IL-6) to govern both optimal T-cell responses and inflammatory resolution, we hypothesised that IL-6 plays an important role in maintaining this balance. Comparison of innate and adaptive immune responses in influenza-infected wild-type control and IL-6-deficient mice revealed striking differences in virus clearance, lung immunopathology and generation of heterosubtypic immunity. Mice lacking IL-6 displayed a profound defect in their ability to mount an anti-viral T-cell response. Failure to adequately control virus was further associated with an enhanced infiltration of inflammatory monocytes into the lung and an elevated production of the pro-inflammatory cytokines, IFN-α and TNF-α. These events were associated with severe lung damage, characterised by profound vascular leakage and death. Our data highlight an essential role for IL-6 in orchestrating anti-viral immunity through an ability to limit inflammation, promote protective adaptive immune responses and prevent fatal immunopathology. Keywords: Adaptive immunity · Heterosubtypic immunity · IL-6 · Innate immunity · Pulmonary damageAdditional supporting information may be found in the online version of this article at the publisher's web-site IntroductionSeasonal influenza infects 5-15% of the global population annually and results in significant morbidity and mortality [1]. Fatal infections are characterised by severe respiratory failure, which is associated with a profound early inflammatory infiltrate, lung haemorrhage and cytokine release [2][3][4]. Disease severity may Correspondence: Dr. Sarah N. Lauder e-mail: LauderSN@cf.ac.uk therefore reflect the balance between immune-mediated control of virus replication and the extent of virus-driven immunopathology. The co-ordinate activities of the innate and adaptive immune systems are likely to contribute to this balance. In order to examine this relationship, we studied the role that the cytokine, IL-6, plays in maintaining this balance. We considered this important, as IL-6 has been reported to correspond with the magnitude of strain-independent viral replication and disease severity both in animal models and in humans [5,6]. Recent data using a mouse model of influenza infection indicate that mice lacking IL-6 are less likely to survive the infection thereby implying a beneficial effect of IL-6 in controlling the infection [7].C 2013 Cardiff University. European Journal of Immunology published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim. www.eji-journal.euThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.2614 Sarah N. Lauder et al. Eur. J. Immunol. 2013. 43: 2613-2625 The impact of IL-6 on the host respon...

T-cell infiltration into tumors represents a critical bottleneck for immune-mediated control of cancer. We previously showed that this bottleneck can be overcome by depleting immunosuppressive Foxp3+ regulatory T cells (Tregs), a process which can increase frequencies of tumor-infiltrating lymphocytes (TILs) through promoting development of specialized portals for lymphocyte entry, namely high endothelial venules (HEVs). In this paper, we used a carcinogen-induced tumor model, that allows for co-evolution of the tumor microenvironment and the immune response, to demonstrate that Treg depletion not only results in widespread disruption to HEV networks in lymph nodes (LNs) but activates CD8+ T cells, which then drive intratumoral HEV development. Formation of these vessels contrasts with ontogenic HEV development in LNs in that the process is dependent on TNF receptor and independent of lymphotoxin β receptor-mediated signaling. These intratumoral HEVs do not express the chemokine CCL21, revealing a previously undescribed intratumoral blood vessel phenotype. We propose a model where Treg depletion enables a self-amplifying loop of T-cell activation, which promotes HEV development, T-cell infiltration, and ultimately, tumor destruction. The findings point to a need to test for HEV development as part of ongoing clinical studies in patients with cancer.

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Background Sensitization to house dust mite (HDM) is a leading cause of allergic rhinitis and asthma. Despite more than 30 HDM‐derived allergens having been identified to date, specific therapeutic approaches do not yet take into account the local sensitization profiles of patients. This study aimed to identify patterns of HDM sensitization in HDM‐allergic adults living in distinct geographic areas, to inform the development of targeted diagnostic and therapeutic tools. Methods Serum samples from 685 HDM‐allergic subjects from Canada, Europe, South Africa, and the USA were tested for levels of IgE specific for 17 micro‐arrayed HDM allergens by ImmunoCAP Immuno Solid‐phase Allergen Chip (ISAC) technology. Results The results confirmed significant geographical variability in sensitization patterns and levels of IgE. In all areas, the major sensitizers were the group 1 and group 2 allergens and Der p 23. Der p 23 was a frequent sensitizer: 64% of the subjects had IgE specific for Der p 23, and 2.3% were monosensitized to it. In South Africa, Der p 23 was the dominant HDM allergen (86% prevalence) and Der p 7 achieved major allergen status (56%). IgE sensitization to HDM was influenced by asthmatic status, levels of allergen exposure, age, race‐ethnicity and smoking status, but not by BMI. Conclusion Sensitization profiles to HDM allergens differ considerably among distinct geographic areas, with Der p 7 and Der p 23 being major sensitizers in South Africa. Such heterogeneity should be taken into account in the diagnosis and treatment of HDM‐allergic patients.

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Human CD4+ αβ T cells are activated via T-cell receptor recognition of peptide epitopes presented by major histocompatibility complex (MHC) class II (MHC-II). The open ends of the MHC-II binding groove allow peptide epitopes to extend beyond a central nonamer core region at both the amino- and carboxy-terminus. We have previously found that these non-bound C-terminal residues can alter T cell activation in an MHC allele-transcending fashion, although the mechanism for this effect remained unclear. Here we show that modification of the C-terminal peptide-flanking region of an influenza hemagglutinin (HA305−320) epitope can alter T-cell receptor binding affinity, T-cell activation and repertoire selection of influenza-specific CD4+ T cells expanded from peripheral blood. These data provide the first demonstration that changes in the C-terminus of the peptide-flanking region can substantially alter T-cell receptor binding affinity, and indicate a mechanism through which peptide flanking residues could influence repertoire selection.

Cockroach allergy is a widespread health problem in the world, associated with the development of asthma. The German and American cockroach species are important producers of a wide variety of allergens. Knowledge of their structure and function contributes to understand their role in allergy and to design tools for diagnosis and immunotherapy.