Antigen presenting cell-targeted proinsulin expression converts insulin-specific CD8(+) T-cell priming to tolerance in autoimmune-prone NOD mice

Type 1 diabetes (T1D) results from autoimmune destruction of insulin-producing pancreatic β cells. Therapies need to incorporate strategies to overcome the genetic defects that impair induction or maintenance of peripheral T-cell tolerance and contribute to disease development. We tested whether the enforced expression of an islet autoantigen in antigen-presenting cells (APC) counteracted peripheral T-cell tolerance defects in autoimmune-prone NOD mice. We observed that insulin-specific CD8+ T cells transferred to mice in which proinsulin was transgenically expressed in APCs underwent several rounds of division and the majority were deleted. Residual insulin-specific CD8+ T cells were rendered unresponsive and this was associated with TCR downregulation, loss of tetramer binding and expression of a range of co-inhibitory molecules. Notably, accumulation and effector differentiation of insulin-specific CD8+ T cells in pancreatic lymph nodes was prominent in non-transgenic recipients but blocked by transgenic proinsulin expression. This shift from T-cell priming to T-cell tolerance exemplifies the tolerogenic capacity of autoantigen expression by APC and the capacity to overcome genetic tolerance defects. This article is protected by copyright. All rights reserved

Prevalence of loneliness and associations with health behaviours and body mass index in 5835 people living with and beyond cancer: a cross-sectional study

Background A cancer diagnosis and its treatment may be an especially isolating experience. Despite evidence that positive health behaviours can improve outcomes for people living with and beyond cancer (LWBC), no studies have examined associations between loneliness and different health behaviours in this population. This study aimed to describe the prevalence of loneliness in a large sample of UK adults LWBC and to explore whether loneliness was associated with multiple health behaviours. Methods Participants were adults (aged ≥ 18 years) diagnosed with breast, prostate or colorectal cancer who completed the Health and Lifestyle After Cancer Survey. Loneliness was reported using the UCLA loneliness score, dichotomised into higher (≥ 6) versus lower (< 6) loneliness. Engagement in moderate-to-vigorous physical activity, dietary intake, smoking status, alcohol use, and self-reported height and weight were recorded. Behaviours were coded to reflect meeting or not meeting the World Cancer Research Fund recommendations for people LWBC. Logistic regression analyses explored associations between loneliness and health behaviours. Covariates were age, sex, ethnicity, education, marital status, living situation, cancer type, spread and treatment, time since treatment, time since diagnosis and number of comorbid conditions. Multiple imputation was used to account for missing data. Results 5835 participants, mean age 67.4 (standard deviation = 11.8) years, completed the survey. 56% were female (n = 3266) and 44% (n = 2553) male, and 48% (n = 2786) were living with or beyond breast cancer, 32% (n = 1839) prostate, and 21% (n = 1210) colorectal. Of 5485 who completed the loneliness scale, 81% (n = 4423) of participants reported lower and 19% (n = 1035) higher loneliness. After adjustment for confounders, those reporting higher levels of loneliness had lower odds of meeting the WCRF recommendations for moderate-to-vigorous physical activity (Odds Ratio [OR] 0.78, 95% Confidence Internal [CI], 0.67, 0.97, p =.028), fruit and vegetable intake (OR 0.81, CI 0.67, 1.00, p =.046), and smoking (OR 0.62, 0.46, 0.84, p =.003). No association was observed between loneliness and the other dietary behaviours, alcohol, or body mass index. Conclusions Loneliness is relatively common in people LWBC and may represent an unmet need. People LWBC who experience higher levels of loneliness may need additional support to improve their health behaviours

Neural origins of human sickness in interoceptive responses to inflammation

BackgroundInflammation is associated with psychological, emotional, and behavioral disturbance, known as sickness behavior. Inflammatory cytokines are implicated in coordinating this central motivational reorientation accompanying peripheral immunologic responses to pathogens. Studies in rodents suggest an afferent interoceptive neural mechanism, although comparable data in humans are lacking.MethodsIn a double-blind, randomized crossover study, 16 healthy male volunteers received typhoid vaccination or saline (placebo) injection in two experimental sessions. Profile of Mood State questionnaires were completed at baseline and at 2 and 3 hours. Two hours after injection, participants performed a high-demand color word Stroop task during functional magnetic resonance imaging. Blood samples were performed at baseline and immediately after scanning.ResultsTyphoid but not placebo injection produced a robust inflammatory response indexed by increased circulating interleukin-6 accompanied by a significant increase in fatigue, confusion, and impaired concentration at 3 hours. Performance of the Stroop task under inflammation activated brain regions encoding representations of internal bodily state. Spatial and temporal characteristics of this response are consistent with interoceptive information flow via afferent autonomic fibers. During performance of this task, activity within interoceptive brain regions also predicted individual differences in inflammation-associated but not placebo-associated fatigue and confusion. Maintenance of cognitive performance, despite inflammation-associated fatigue, led to recruitment of additional prefrontal cortical regions.ConclusionsThese findings suggest that peripheral infection selectively influences central nervous system function to generate core symptoms of sickness and reorient basic motivational states

Analysis of mouse dendritic cell migration in vivo upon subcutaneous and intravenous injection

Dendritic cells (DC) have an increasingly important role in vaccination therapy; therefore, this study sought to determine the migratory capacity and immunogenic function of murine bone-marrow (BM)-derived DC following subcutaneous (s.c.) and intravenous (i.v.) injection in vivo. DC were enriched from BM cultures using metrizamide. Following centrifugation, the low-buoyant density cells, referred to throughout as DC, were CD11chigh, Iab high, B7-1high and B7-2high and potently activated alloreactive T cells in mixed lymphocyte reactions (MLR). In contrast, the high-density cells expressed low levels of the above markers, comprised mostly of granulocytes based on GR1 expression, and were poor stimulators in MLR. Following s.c. injection of fluorescently labelled cells into syngeneic recipient mice, DC but not granulocytes migrated to the T-dependent areas of draining lymph nodes (LN). DC numbers in LN were quantified by flow-cytometric analysis, on 1, 2, 3, 5 and 7 days following DC transfer. Peak numbers of around 90 DC per draining LN were found at 2 days. There was very little migration of DC to non-draining LN, thymus or spleen at any of the time-points studied. In contrast, following i.v. injection, DC accumulated mainly in the spleen, liver and lungs of recipient mice but were largely absent from peripheral LN and thymus. The ability of DC to induce T-cell-mediated immune responses was examined using trinitrobenzenesulphate (TNBS)-derivatized DC (TNBS-DC) to sensitize for contact hypersensitivity responses (CHS) in naive syngeneic recipients. Following s.c. injection, as few as 105 TNBS-DC, but not TNBS-granulocytes, sensitized for CHS responses. However, the same number of TNBS-DC failed to induce CHS following i.v. injection. In summary, this study provides new and quantitative data on the organ specific migration of murine BM-derived DC following s.c. and i.v. injection. The demonstration that the route of DC administration determines the potency of CHS induction, strongly suggests that the route of immunization should be considered in the design of vaccine protocols using DC