Quantifying Memory CD8 T Cells Reveals Regionalization of Immunosurveillance.

Memory CD8 T cells protect against intracellular pathogens by scanning host cell surfaces; thus, infection detection rates depend on memory cell number and distribution. Population analyses rely on cell isolation from whole organs, and interpretation is predicated on presumptions of near complete cell recovery. Paradigmatically, memory is parsed into central, effector, and resident subsets, ostensibly defined by immunosurveillance patterns but in practice identified by phenotypic markers. Because isolation methods ultimately inform models of memory T cell differentiation, protection, and vaccine translation, we tested their validity via parabiosis and quantitative immunofluorescence microscopy of a mouse memory CD8 T cell population. We report three major findings: lymphocyte isolation fails to recover most cells and biases against certain subsets, residents greatly outnumber recirculating cells within non-lymphoid tissues, and memory subset homing to inflammation does not conform to previously hypothesized migration patterns. These results indicate that most host cells are surveyed for reinfection by segregated residents rather than by recirculating cells that migrate throughout the blood and body.

Sensing and alarm function of resident memory CD8⁺ T cells.

CD8(+) T cells eliminate intracellular infections through two contact-dependent effector functions: cytolysis and secretion of antiviral cytokines. Here we identify the following additional function for memory CD8(+) T cells that persist at front-line sites of microbial exposure: to serve as local sensors of previously encountered antigens that precipitate innate-like alarm signals and draw circulating memory CD8(+) T cells into the tissue. When memory CD8(+) T cells residing in the female mouse reproductive tract encountered cognate antigen, they expressed interferon-γ (IFN-γ), potentiated robust local expression of inflammatory chemokines and induced rapid recruitment of circulating memory CD8(+) T cells. Anamnestic responses in front-line tissues are thus an integrated collaboration between front-line and circulating populations of memory CD8(+) T cells, and vaccines should establish both populations to maximize rapid responses.

Interleukin-2-Dependent Allergen-Specific Tissue-Resident Memory Cells Drive Asthma.

Exposure to inhaled allergens generates T helper 2 (Th2) CD4(+) T cells that contribute to episodes of inflammation associated with asthma. Little is known about allergen-specific Th2 memory cells and their contribution to airway inflammation. We generated reagents to understand how endogenous CD4(+) T cells specific for a house dust mite (HDM) allergen form and function. After allergen exposure, HDM-specific memory cells persisted as central memory cells in the lymphoid organs and tissue-resident memory cells in the lung. Experimental blockade of lymphocyte migration demonstrated that lung-resident cells were sufficient to induce airway hyper-responsiveness, which depended upon CD4(+) T cells. Investigation into the differentiation of pathogenic Trm cells revealed that interleukin-2 (IL-2) signaling was required for residency and directed a program of tissue homing migrational cues. These studies thus identify IL-2-dependent resident Th2 memory cells as drivers of lung allergic responses.

Challenges and gaps in immunosafety evaluation of therapeutics: An IQ DruSafe survey.

Immunotoxicology/immunosafety science is rapidly evolving, with novel modalities and immuno-oncology among the primary drivers of new tools and technologies. The Immunosafety Working Group of IQ/DruSafe sought to better understand some of the key challenges in immunosafety evaluation, gaps in the science, and current limitations in methods and data interpretation. A survey was developed to provide a baseline understanding of the needs and challenges faced in immunosafety assessments, the tools currently being applied across the industry, and the impact of feedback received from regulatory agencies. This survey also focused on current practices and challenges in conducting the T-cell-dependent antibody response (TDAR) and the cytokine release assay (CRA). Respondents indicated that ICH S8 guidance was insufficient for the current needs of the industry portfolio of immunomodulators and novel modalities and should be updated. Other challenges/gaps identified included translation of nonclinical immunosafety assessments to the clinic, and lack of relevant nonclinical species and models in some cases. Key areas of emerging science that will add future value to immunotoxicity assessments include development of additional in vitro and microphysiological system models, as well as application of humanized mouse models. Efforts are ongoing in individual companies and consortia to address some of these gaps and emerging science.

Preexisting high frequencies of memory CD8+ T cells favor rapid memory differentiation and preservation of proliferative potential upon boosting.

Memory CD8+ T cell quantity and quality determine protective efficacy against reinfection. Heterologous prime boost vaccination minimizes contraction of anamnestic effectors and maximizes memory CD8+ T cell quantity but reportedly erodes proliferative potential and protective efficacy. This study exploited heterologous prime boost vaccination to discover parameters regulating effector CD8+ T cell contraction and memory differentiation. When abundant memory T cells were established, boosting induced only 5-8 cell divisions, unusually rapid memory T cell differentiation as measured by phenotype and mitochondrial bioenergetic function, long-lived survival of 50% of effector T cells, and preservation of proliferative potential. Conversely, boosting in situations of low memory CD8+ T cell frequencies induced many cell divisions, increased contraction of effector cells, and caused senescence, low mitochondrial membrane potential, and poorly protective memory. Thus, anamnestic memory T cell differentiation is flexible, and abundant quantity can be achieved while maximizing protective efficacy and preserving proliferative potential.

Normalizing the environment recapitulates adult human immune traits in laboratory mice.

Our current understanding of immunology was largely defined in laboratory mice, partly because they are inbred and genetically homogeneous, can be genetically manipulated, allow kinetic tissue analyses to be carried out from the onset of disease, and permit the use of tractable disease models. Comparably reductionist experiments are neither technically nor ethically possible in humans. However, there is growing concern that laboratory mice do not reflect relevant aspects of the human immune system, which may account for failures to translate disease treatments from bench to bedside. Laboratory mice live in abnormally hygienic specific pathogen free (SPF) barrier facilities. Here we show that standard laboratory mouse husbandry has profound effects on the immune system and that environmental changes produce mice with immune systems closer to those of adult humans. Laboratory mice--like newborn, but not adult, humans--lack effector-differentiated and mucosally distributed memory T cells. These cell populations were present in free-living barn populations of feral mice and pet store mice with diverse microbial experience, and were induced in laboratory mice after co-housing with pet store mice, suggesting that the environment is involved in the induction of these cells. Altering the living conditions of mice profoundly affected the cellular composition of the innate and adaptive immune systems, resulted in global changes in blood cell gene expression to patterns that more closely reflected the immune signatures of adult humans rather than neonates, altered resistance to infection, and influenced T-cell differentiation in response to a de novo viral infection. These data highlight the effects of environment on the basal immune state and response to infection and suggest that restoring physiological microbial exposure in laboratory mice could provide a relevant tool for modelling immunological events in free-living organisms, including humans.

No struggle, no progress: Taking the anti-racism conversation to a deeper level.

In order to promote ongoing dialogues about how to address racism in health care, the 2021 Forum on Behavioral Science included a workshop on how to take antiracism activities and conversations to a deeper level than what is typically offered. The workshop followed up on a previous antiracism plenary presentation at the 2020 Forum and was intentionally created to keep the importance of antiracism efforts on the forefront of behavioral science and medical education. The currently described presentation provided some background on how health inequity evolved in the United States. It also included information on the role that racism has played in the development of inequities in health care, the profession of medicine and medical education. Presenters included several activities specifically chosen to promote honest, open conversations about power imbalances that promote discrimination on the micro and macrosystem level. Participants were encouraged to start working on specific goals and ideas on how to conduct these activities and challenging conversations in their home institutions.

Immune Pharmacodynamic Responses of the Novel Cancer Immunotherapeutic Imprime PGG in Healthy Volunteers.

Imprime PGG (Imprime) is an i.v. administered, yeast ß-1,3/1,6 glucan in clinical development with checkpoint inhibitors. Imprime-mediated innate immune activation requires immune complex formation with naturally occurring IgG anti-ß glucan Abs (ABA). We administered Imprime to healthy human volunteers to assess the necessity of ABA for Imprime-mediated immunopharmacodynamic (IPD) changes. Imprime (4 mg/kg) was administered i.v. in single and multiple infusions. Subsets of subjects were premedicated with antihistamine and corticosteroid. Peripheral blood was measured before, during and after Imprime administration for IPD changes (e.g., ABA, circulating immune complexes, complement activation, complete blood counts, cytokine/chemokine, and gene expression changes). IPD changes were analyzed based on pretreatment serum ABA levels: low-ABA (<20 µg/ml), mid-ABA (≥20-50 µg/ml), and high-ABA (≥50 µg/ml). At the end of infusion, free serum ABA levels decreased, circulating immune complex levels increased, and complement activation was observed. At ∼1-4 h after end of infusion, increased expression of cytokines/chemokines, a 1.5-4-fold increase in neutrophil and monocyte counts and a broad activation of innate immune genes were observed. Low-ABA subjects typically showed minimal IPD changes except when ABA levels rose above 20 µg/ml after repeated Imprime dosing. Mild-to-moderate infusion-related reactions occurred in subjects with ABA ≥20 µg/ml. Premedications alleviated some of the infusion-related reactions, but also inhibited cytokine responses. In conclusion, ABA levels, being critical for Imprime-mediated immune activation may provide a plausible, mechanism-based biomarker to identify patients most likely to respond to Imprime-based anticancer immunotherapy.

Racism and persistent disparities: Difficult conversations on the road to equity.

The convergence of the major social events of the COVID 19 epidemic and the racial protests around the George Floyd killing spurred many conversations and calls to action for racial justice. The Behavioral Science Forum of 2020 invited a plenary presentation to discuss guidelines for medical education institutions to improve their anti-racism curricula. The plenary aimed to put forward the personal experiences of family medicine faculty contributing to dismantling racism in their institutions. Presenters provided (1) a breakdown of the step by step process of addressing these issues with faculty, residents, and staff, (2) guidelines for improving recruitment and retention of diverse student populations, and (3) small group breakouts and a subsequent discussion forum for participants to bring their experiences into the conversation and develop their personal call to action. The wrap-up discussion and "Zoom chat" yielded emotional responses and specific ideas for participants and other faculty in medical education to do their part in developing anti-racism curricula.

Canadian Dietitians' Understandings of, Attitudes Toward, and Engagement in Social Justice and Advocacy.

Purpose: To explore Canadian dietitians' understandings of, attitudes towards, and engagement in socially just dietetic practice and advocacy.Methods: An online semi-qualitative survey sent to Canadian dietitians.Results: Respondents' understanding of social justice and socially just dietetics practice highlights the unique ways that social injustice and health inequities may be addressed by dietitians. Overall, respondents had a positive attitude toward dietitians' roles in social justice advocacy. Support for dietitians' advocacy roles was highest for food-related concerns, but it declined for concerns with indirect connections to dietitians' food and nutrition expertise (e.g., environment). However, respondents still had uncertainty and divided perspectives concerning if and how social justice fits within dietitians' scope of practice. They also had concerns about barriers that they felt limit dietitians' ability to perform socially just practice. Respondents shared efforts to engage in socially just practice at intrapersonal, interpersonal, and structural levels.Conclusions: Dietitians could be a critical influence on the determinants of health. This research points strongly to the need for a framework for socially just dietetic practice and advocacy that delineates what social justice looks like across the array of settings in which dietitians practice and within the array of fora that dietitians advocate to support nutrition and health.

"It was Like Magic": Relationships Supporting Compassion, Creativity, and Sense of Coherence in Nutrition Students.

The purpose of this exploratory research was to understand the experiences and learnings of dietetic and nutrition students following a 3-week intensive summer course designed to enhance students' understandings of compassion, creativity, and sense of coherence as they apply to personal growth and socially just professional practice. Seven of 15 students participated in one-on-one, semi-structured interviews. Data analysis was conducted using inductive thematic analysis, resulting in 3 meta-themes: (i) personal meaning and sense making, (ii) relational and power dynamics, and (iii) disruption; participants contextualized these themes via a dynamic interplay within and among the domains of self, pedagogy, and practice. As a result of taking this course, participants developed an enhanced sense of coherence, self-compassion, well-being, and a more equity-focused understanding of health. Student development may have been achieved through attending to student experience and a relational pedagogical epistemology that allowed students to make personal, interpersonal, and systemic connections among their own subjective experiences, the experiences of peers, and broader social impacts on health. Given nutrition classrooms are largely positivist, it is important to consider how these environments as relational contexts may support or undermine compassion, sense of coherence, and ultimately the health and well-being of students.

Exploring Social Justice Advocacy in Dietetic Education: A Content Analysis.

PURPOSE: To explore the extent to which knowledge- and skill-based learning regarding social justice and/or social justice advocacy is included in the course descriptions of required courses of accredited, English-speaking dietitian training programs in Canada. METHODS: This study is a mixed-methods content analysis of required course descriptions sampled from university academic calendars for accredited, English-speaking dietitian training programs across Canada. RESULTS: Quantitative analysis showed that required course descriptions (n = 403) included few instances of social justice-related terminology (n = 63). Two themes emerged from the qualitative analysis: competing conceptualizations of social issues and dietitians' roles; prioritization of science-based knowledge and ways of knowing. CONCLUSIONS: Accredited, English-speaking dietitian training programs in Canada appear to include little knowledge- or skill-based learning regarding social justice issues and advocacy. Supporting future dietitians to pursue leadership roles in redressing social injustices and socially just dietetic practice may require more explicit education and training about social justice issues and advocacy skills.

IL-15-Independent Maintenance of Tissue-Resident and Boosted Effector Memory CD8 T Cells.

IL-15 regulates central and effector memory CD8 T cell (TCM and TEM, respectively) homeostatic proliferation, maintenance, and longevity. Consequently, IL-15 availability hypothetically defines the carrying capacity for total memory CD8 T cells within the host. In conflict with this hypothesis, previous observations demonstrated that boosting generates preternaturally abundant TEM that increases the total quantity of memory CD8 T cells in mice. In this article, we provide a potential mechanistic explanation by reporting that boosted circulating TEM do not require IL-15 for maintenance. We also investigated tissue-resident memory CD8 T cells (TRM), which protect nonlymphoid tissues from reinfection. We observed up to a 50-fold increase in the total magnitude of TRM in mouse mucosal tissues after boosting, suggesting that the memory T cell capacity in tissues is flexible and that TRM may not be under the same homeostatic regulation as primary central memory CD8 T cells and TEM Further analysis identified distinct TRM populations that depended on IL-15 for homeostatic proliferation and survival, depended on IL-15 for homeostatic proliferation but not for survival, or did not depend on IL-15 for either process. These observations on the numerical regulation of T cell memory indicate that there may be significant heterogeneity among distinct TRM populations and also argue against the common perception that developing vaccines that confer protection by establishing abundant TEM and TRM will necessarily erode immunity to previously encountered pathogens as the result of competition for IL-15.

Cutting edge: resident memory CD8 T cells occupy frontline niches in secondary lymphoid organs.

Resident memory CD8 T cells (TRM) are a nonrecirculating subset positioned in nonlymphoid tissues to provide early responses to reinfection. Although TRM are associated with nonlymphoid tissues, we asked whether they populated secondary lymphoid organs (SLO). We show that a subset of virus-specific memory CD8 T cells in SLO exhibit phenotypic signatures associated with TRM, including CD69 expression. Parabiosis revealed that SLO CD69(+) memory CD8 T cells do not circulate, defining them as TRM. SLO TRM were overrepresented in IL-15-deficient mice, suggesting independent regulation compared with central memory CD8 T cells and effector memory CD8 T cells. These cells were positioned at SLO entry points for peripheral Ags: the splenic marginal zone, red pulp, and lymph node sinuses. Consistent with a potential role in guarding SLO pathogen entry points, SLO TRM did not vacate their position in response to peripheral alarm signals. These data extend the range of tissue resident memory to SLO.

Antigen-independent differentiation and maintenance of effector-like resident memory T cells in tissues.

Differentiation and maintenance of recirculating effector memory CD8 T cells (T(EM)) depends on prolonged cognate Ag stimulation. Whether similar pathways of differentiation exist for recently identified tissue-resident effector memory T cells (T(RM)), which contribute to rapid local protection upon pathogen re-exposure, is unknown. Memory CD8αß(+) T cells within small intestine epithelium are well-characterized examples of T(RM), and they maintain a long-lived effector-like phenotype that is highly suggestive of persistent Ag stimulation. This study sought to define the sources and requirements for prolonged Ag stimulation in programming this differentiation state, including local stimulation via cognate or cross-reactive Ags derived from pathogens, microbial flora, or dietary proteins. Contrary to expectations, we found that prolonged cognate Ag stimulation was dispensable for intestinal T(RM) ontogeny. In fact, chronic antigenic stimulation skewed differentiation away from the canonical intestinal T cell phenotype. Resident memory signatures, CD69 and CD103, were expressed in many nonlymphoid tissues including intestine, stomach, kidney, reproductive tract, pancreas, brain, heart, and salivary gland and could be driven by cytokines. Moreover, TGF-ß-driven CD103 expression was required for T(RM) maintenance within intestinal epithelium in vivo. Thus, induction and maintenance of long-lived effector-like intestinal T(RM) differed from classic models of T(EM) ontogeny and were programmed through a novel location-dependent pathway that was required for the persistence of local immunological memory.

Designing Effective Mentorship for Underrepresented Faculty in Academic Medicine.

BACKGROUND AND OBJECTIVES: A dearth of training and resources exists for mentors to address the unique needs of faculty from racial/ethnic groups that are underrepresented in medicine (URiM). Mentoring Underrepresented Faculty for Academic Excellence (MUFAE) was a multi-institutional mentoring program designed to provide mentors where there were none. METHODS: In 2020, 25 early career URiM faculty mentees each were paired with advanced faculty, and pairs met individually for monthly calls for 1 year. Mentees completed pre- and postassessment surveys regarding their experience in the program. Mentees and mentors also participated in virtual group check-ins where they gave feedback on their experience to program leaders while also networking with fellow participants. RESULTS: Twenty-two of the 25 mentor-mentee pairs (88%) completed the program, and 17 of the 22 (77%) mentees completed the pre- and postsurveys. Survey responses showed significant increases in mentees reports of feeling they received mentorship focused on their needs as URiM faculty members, feeling equipped to advance in their careers, and feeling supported in their efforts to complete antiracism/health-equity programs. Feedback at the check-ins indicated that URiM mentors appreciated the opportunities to talk about their own frustrations and that White mentors appreciated having an increased understanding of challenges that their URIM colleagues faced. CONCLUSIONS: MUFAE is a model for academic societies to address the lack of mentors for URiM faculty. Mentees and mentors found the experience a meaningful one that fills a need in academic mentoring.

Knowledge of psychotropics and prescribing preferences of family physicians: a preliminary study.

OBJECTIVE: Family doctors often provide care for their patients' mental health needs. This study was designed to survey their opinions and actual practice of providing mental health care, specifically, prescribing psychotropic medication to outpatients with mild/moderate mental health disorders. METHOD: A group of 241 family medicine faculty and residents completed a self-administered survey designed to evaluate their comfort level with providing brief office counseling and psychotropic medication to their patients with mental health disorders. RESULTS: The majority of the sample reported that they prescribe psychotropic medication to their patients, despite often assessing their knowledge of psychotropics as absent or marginal. Most of the sample expressed strong interest in learning more about prescribing psychiatric medications. CONCLUSION: Results of the study suggest the need for improved training of family physicians who often prescribe psychiatric medications for outpatients with mental health disorders.

A global comparative study of wealth-pain gradients: Investigating individual- and country-level associations.

Pain is a significant yet underappreciated dimension of population health. Its associations with individual- and country-level wealth are not well characterized using global data. We estimate both individual- and country-level wealth inequalities in pain in 51 countries by combining data from the World Health Organization's World Health Survey with country-level contextual data. Our research concentrates on three questions: 1) Are inequalities in pain by individual-level wealth observed in countries worldwide? 2) Does country-level wealth also relate to pain prevalence? 3) Can variations in pain reporting also be explained by country-level contextual factors, such as income inequality? Analytical steps include logistic regressions conducted for separate countries, and multilevel models with random wealth slopes and resultant predicted probabilities using a dataset that pools information across countries. Findings show individual-level wealth negatively predicts pain almost universally, but the association strength differs across countries. Country-level contextual factors do not explain away these associations. Pain is generally less prevalent in wealthier countries, but the exact nature of the association between country-level wealth and pain depends on the moderating influence of country-level income inequality, measured by the Gini index. The lower the income inequality, the more likely it is that poor countries experience the highest and rich countries the lowest prevalence of pain. In contrast, the higher the income inequality, the more nonlinear the association between country-level wealth and pain reporting such that the highest prevalence is seen in highly nonegalitarian middle-income countries. Our findings help to characterize the global distribution of pain and pain inequalities, and to identify national-level factors that shape pain inequalities.

Cooperative CAR targeting to selectively eliminate AML and minimize escape.

Acute myeloid leukemia (AML) poses a singular challenge for chimeric antigen receptor (CAR) therapy owing to its phenotypic heterogeneity and similarity to normal hematopoietic stem/progenitor cells (HSPCs). Here we expound a CAR strategy intended to efficiently target AML while minimizing HSPC toxicity. Quantification of target expression in relapsed/refractory patient samples and normal HSPCs reveals a therapeutic window for gated co-targeting of ADGRE2 and CLEC12A: We combine an attenuated ADGRE2-CAR with a CLEC12A-chimeric costimulatory receptor (ADCLEC.syn1) to preferentially engage ADGRE2posCLEC12Apos leukemic stem cells over ADGRE2lowCLEC12Aneg normal HSPCs. ADCLEC.syn1 prevents antigen escape in AML xenograft models, outperforms the ADGRE2-CAR alone and eradicates AML despite proximate myelopoiesis in humanized mice. Off-target HSPC toxicity is similar to that of a CD19-CAR and can be mitigated by reducing CAR T cell-derived interferon-γ. Overall, we demonstrate the ability of target density-adapted cooperative CAR targeting to selectively eliminate AML and potentially obviate the need for hematopoietic rescue.

A global study of pain prevalence across 52 countries: examining the role of country-level contextual factors.

ABSTRACT: There is wide variation in population-level pain prevalence estimates in studies of survey data around the world. The role of country-level social, economic, and political contextual factors in explaining this variation has not been adequately examined. We estimated the prevalence of unspecified pain in adults aged 25+ years across 52 countries using data from the World Health Survey 2002 to 2004. Combining data sources and estimating multilevel regressions, we compared country-level pain prevalence and explored which country-level contextual factors explain cross-country variations in prevalence, accounting for individual-level demographic factors. The overall weighted age- and sex-standardized prevalence of pain across countries was estimated to be 27.5%, with significant variation across countries (ranging from 9.9% to 50.3%). Women, older persons, and rural residents were significantly more likely to report pain. Five country-level variables had robust and significant associations with pain prevalence: the Gini Index, population density, the Gender Inequality Index, life expectancy, and global region. The model including Gender Inequality Index explained the most cross-country variance. However, even when accounting for country-level variables, some variation in pain prevalence remains, suggesting a complex interaction between personal, local, economic, and political impacts, as well as inherent differences in language, interpretations of health, and other difficult to assess cultural idiosyncrasies. The results give new insight into the high prevalence of pain around the world and its demonstrated association with macrofactors, particularly income and gender inequalities, providing justification for regarding pain as a global health priority.