Cells undergoing apoptosis are efficiently located and engulfed by phagocytes. The mechanisms by which macrophages, the professional scavenging phagocytes of apoptotic cells, are attracted to sites ...of apoptosis are poorly defined. Here we show that CX3CL1/fractalkine, a chemokine and intercellular adhesion molecule, is released rapidly from apoptotic lymphocytes, via caspase- and Bcl-2-regulated mechanisms, to attract macrophages. Effective chemotaxis of macrophages to apoptotic lymphocytes is dependent on macrophage fractalkine receptor, CX3CR1. CX3CR1 deficiency caused diminished recruitment of macrophages to germinal centers of lymphoid follicles, sites of high-rate B-cell apoptosis. These results provide the first demonstration of chemokine/chemokine-receptor activity in the navigation of macrophages toward apoptotic cells and identify a mechanism by which macrophage infiltration of tissues containing apoptotic lymphocytes is achieved.
To investigate the role of lymphotoxin (LT) in Sjögren's syndrome (SS) and in mucosal associated lymphoid tissue (MALT)‐lymphoma, we made transgenic mice (Amy1‐LTαβ) that targeted LTα and LTβ to the ...salivary and lacrimal glands. Amy1‐LTαβ mice developed atrophic salivary and lacrimal glands that contained tertiary lymphoid organs (TLOs) and had reduced tear production. Amy1‐LTαβ mice developed cervical lymphadenopathy but not MALT‐lymphoma. TLO formation in the salivary and lacrimal glands of Amy1‐LTαβ was not sufficient to induce autoimmunity as measured by autoantibody titres.
A mouse in which lymphotoxin is overexpressed in salivary and lacrimal glands exhibits some characteristics of Sjögren's syndrome, including lymphoid accumulations, termed tertiary lymphoid organs, at the sites of transgene expression, fewer tears, and enlarged draining LNs.
Immune-deficient mice, reconstituted with human stem cells, have been used to analyze human immune responses in vivo. Although they have been used to study immune responses to xenografts, allografts, ...and pathogens, there have not been models of autoimmune disease in which the mechanisms of the pathologic process can be analyzed. We have found that reconstituted "humanized" mice treated with anti-CTLA-4 Ab (ipilimumab) develop autoimmune disease characterized by hepatitis, adrenalitis, sialitis, anti-nuclear Abs, and weight loss. Induction of autoimmunity involved activation of T cells and cytokine production, and increased infiltration of APCs. When anti-CTLA-4 mAb-treated mice were cotreated with anti-CD3 mAb (teplizumab), hepatitis and anti-nuclear Abs were no longer seen and weight loss did not occur. The anti-CD3 blocked proliferation and activation of T cells, release of IFN-γ and TNF, macrophage infiltration, and release of IP-10 that was induced with anti-CTLA-4 mAb. We also found increased levels of T regulatory cells (CD25(+)CD127(-)) in the spleen and mesenteric lymph nodes in the mice treated with both Abs and greater constitutive phosphorylation of STAT5 in T regulatory cells in spleen cells compared with mice treated with anti-CTLA-4 mAb alone. We describe a model of human autoimmune disease in vivo. Humanized mice may be useful for understanding the mechanisms of biologics that are used in patients. Hepatitis, lymphadenopathy, and other inflammatory sequelae are adverse effects of ipilimumab treatment in humans, and this study may provide insights into this pathogenesis and the effects of immunologics on autoimmunity.
Camouflaging (or otherwise referred to as masking or passing) involves hiding one’s autistic-related characteristics and differences to get by in social situations in predominantly non-autistic ...societies. Very little is known to date about the course of camouflaging motivations and strategies over time or the psychosocial factors that may influence autistic people’s camouflaging choices and trajectories. In an exploratory qualitative study within an Asian sociocultural context, we interviewed 11 Singaporean autistic adults (9 males, 2 females, aged 22–45 years) about their camouflaging experiences to better understand (1) their camouflaging motivations and strategies over time, and (2) related psychosocial influences. Organised across four phases (pre-camouflaging, beginnings, continuity and change over time), 17 themes relating to camouflaging motivations and 8 themes relating to strategies were identified. The earliest camouflaging motivations were predominantly relational, linked to a negative self-identity that had been shaped by adverse social experiences. Camouflaging strategies became increasingly complex and integrated into one’s sense of self over time. Our findings highlight the role of psychosocial pressures precipitating camouflaging and emphasise the need for individual and societal changes, including moving towards enhanced acceptance and inclusion to reduce psychosocial pressures on autistic people to camouflage.
Lay Abstract
Over their lifetimes, many autistic people learn to camouflage (hide or mask) their autism-related differences to forge relationships, find work and live independently in largely non-autistic societies. Autistic adults have described camouflaging as a ‘lifetime of conditioning . . . to act normal’ involving ‘years of effort’, suggesting that camouflaging develops over an autistic person’s lifetime and may start early on, in childhood or adolescence. Yet, we know very little about why and how autistic people start to camouflage, or why and how their camouflaging behaviours continue or change over time. We interviewed 11 Singaporean autistic adults (9 male, 2 female, 22–45 years old) who shared their camouflaging experiences. We found that autistic adults’ earliest motivations to camouflage were largely related to the desire to fit in and connect with others. They also camouflaged to avoid difficult social experiences (such as being teased or bullied). Autistic adults shared that their camouflaging behaviours became more complex and that, for some, camouflaging became a part of their self-identity over time. Our findings suggest that society should not pathologise autistic differences, but instead accept and include autistic people, to reduce the pressure on autistic people to hide who they truly are.
Lymphatic vessels (LVs) are important structures for antigen presentation, for lipid metabolism, and as conduits for tumor metastases, but they have been difficult to visualize in vivo . Prox1 is a ...transcription factor that is necessary for lymphangiogenesis in ontogeny and the maintenance of LVs. To visualize LVs in the lymph node of a living mouse in real time, we made the ProxTom transgenic mouse in a C57BL/6 background using red fluorescent LVs that are suitable for in vivo imaging. The ProxTom transgene contained all Prox1 regulatory sequences and was faithfully expressed in LVs coincident with endogenous Prox1 expression. The progenies of a ProxTom × Hec6stGFP cross were imaged using two-photon laser scanning microscopy, allowing the simultaneous visualization of LVs and high endothelial venules in a lymph node of a living mouse for the first time. We confirmed the expression of Prox1 in the adult liver, lens, and dentate gyrus. These intensely fluorescent mice revealed the expression of Prox1 in three novel sites: the neuroendocrine cells of the adrenal medulla, megakaryocytes, and platelets. The novel sites identified herein suggest previously unknown roles for Prox1. The faithful expression of the fluorescent reporter in ProxTom LVs indicates that these mice have potential utility in the study of diseases as diverse as lymphedema, filariasis, transplant rejection, obesity, and tumor metastasis.
IntroductionType 1 diabetes (T1D) is caused by autoimmune destruction of the insulin-producing β cells in the pancreatic islets, leading to insulinopenia and hyperglycaemia. Genetic analyses indicate ...that alterations of the interleukin-2 (IL-2) pathway mediating immune activation and tolerance predispose to T1D, specifically the polymorphic expression of the IL-2 receptor-α chain (CD25) on T lymphocytes. Replacement of physiological doses of IL-2 could restore self-tolerance and prevent further autoimmunity by enhancing the function of CD4+ T regulatory cells (Tregs) to limit the activation of auto reactive T effector cells (Teffs). In this experimental medicine study, we use an adaptive trial design to determine the optimal dosing regimen for IL-2 to improve Treg function while limiting activation of Teffs in participants with T1D.Methods and analysisThe Adaptive study of IL-2 dose frequency on Tregs in type 1 diabetes(DILfrequency) is a mechanistic, non-randomised, repeat dose open-label, response-adaptive study of 36 participants with T1D. The objective is to establish the optimal dose and frequency of ultra-low dose IL-2: to increase Treg frequency within the physiological range, to increase CD25 expression on Tregs, without increasing CD4+ Teffs. DILfrequency has an initial learning phase where 12 participants are allocated to six different doses and frequencies followed by an interim statistical analysis. After analysis of the learning phase, the Dose and Frequency Committee will select the optimal targets for Treg frequency, Treg CD25 expression and Teff frequency. Three groups of eight participants will be treated consecutively in the confirming phase. Each dose and frequency selected will be based on statistical analysis of all data collected from the previous groups.EthicsEthical approval for DILfrequency was granted on 12 August 2014.ResultsThe results of this study will be reported, through peer-reviewed journals, conference presentations and an internal organisational report.Trial registration numbersNCT02265809, ISRCTN40319192, CRN17571.
Serious infections of the head and neck cause lymphedema that can lead to airway compromise and oropharyngeal obstruction. Lymphangiogenesis occurs in the head and neck during infection and after ...immunization. The goal of this project was to develop tools to image lymphatic vessels in living animals and to be able to isolate individual lymphatic endothelial cells in order to quantify changes in single cells caused by inflammation.
The ProxTom transgenic red-fluorescent reporter mouse was developed specifically for the purpose of imaging lymphatic vessels in vivo. Prox1 is a transcription factor that is necessary for lymphangiogenesis in development and for the maintenance of lymphatics in adulthood. Mice were immunized and their lymphatic vessels in lymph nodes were imaged in vivo. Individual lymphatic endothelial cells were isolated by means of their fluorescence.
The ProxTom transgene has the red-fluorescent reporter td-Tomato under the control of Prox1 regulatory elements. tdTomato was faithfully expressed in lymphatic vessels coincident with endogenous Prox1 expression. We show lymphangiogenesis in vivo after immunization and demonstrate a method for the isolation of lymphatic endothelial cells by their tdTomato red-fluorescence.
The faithful expression of the red-fluorescent reporter in the lymphatic vessels of ProxTom means that these mice have proven utility for in vivo study of lymphatic vessels in the immune response. ProxTom has been made available for distribution from the Jackson Laboratory: http://jaxmice.jax.org/strain/018128.html .
In Burkitt's lymphoma (BL), apoptosis occurs at high frequency alongside uncontrolled proliferation. Macrophages infiltrate these tumours in large numbers and engage in the phagocytic clearance of ...apoptotic cells
in situ. Here we tested the hypothesis that apoptosis of BL cells may provide a mechanism for recruitment of macrophages to these tumours. We show that monocytes and macrophages, but not neutrophils, preferentially migrated to apoptotic BL cells
in vitro. Transfection of BL cells with the anti-apoptotic gene
bcl-2 both prevented apoptosis and abolished macrophage chemotaxis. Macrophage migration to BL populations correlated well with the number of apoptotic BL cells present (the Pearson correlation
r=0.81,
p<0.0001). Chemoattraction of murine macrophages to apoptotic human BL cells demonstrated that the mechanism was conserved across these species. In an attempt to identify the macrophage receptors involved in this process, we investigated whether CD14 and CD36, two receptors important in the phagocytic clearance of apoptotic cells, were also involved in the chemotactic macrophage response. We found that bone marrow-derived macrophages from CD14
−/− and CD36
−/− mice moved as well as wild-type macrophages in chemotaxis assays towards apoptotic BL cells. Migrating macrophages were found to be up-regulated in their expression of CD14, however, suggesting that, although this receptor does not appear to be required for ‘sensing’ apoptotic cells, it may be up-regulated on the surface of the migrating macrophage in readiness for apoptotic corpse clearance.
This paper thinks with the concept of intertextuality to consider the multiple intersecting power structures inside and outside of literary education in secondary schools that continue to dominate ...text selection policies and teaching practices. We draw on our research with in-service teachers to reconsider how intertextual networks circulate on multiple levels: textual, social, cultural, and institutional. Although the concept of intertextuality has been activated as an alternative to rarified conceptualisations of literary heritage, as we unpack in this paper, intertextuality often distributes, reinforces, and perpetuates canonical power structures such as institutional whiteness, and Euro western values in secondary school subjects that feature literary studies. Rather than abandoning intertextuality, we attempt to tease out how it operates in various registers in schooling and we suggest how critically engaging with the concept might provide a way forward for English study in the twenty-first century.
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