A Retrospective Analysis of Leadership, Awardees, and Member Gender Representation of the Canadian Society for Immunology

The Canadian Society for Immunology (CSI) established a formal Equity, Diversity, and Inclusion (EDI) Committee with the goal of providing EDI advocacy and leadership within the CSI, as well as in the broader scientific community. A first task of this committee was to review the publicly available historical data on gender representation within the CSI's membership, leadership, award recipients, and conference chairs/presenters as a step in establishing a baseline reference point and monitoring the trajectory of future success in achieving true inclusion. We found that, except for overall membership and a specific subset of awards, all categories showed a historical bias toward men, particularly prior to 2010. Bias persists in various categories, evident even in recent years. However, we note an encouraging trend toward greater gender parity, particularly in the roles of President, symposium presenters, and workshop chairs, especially from 2017 onward. We present these findings as well as our recommendations to enhance inclusivity. These include a more comprehensive collection and secure storage of self-identification data, emphasis on EDI as an essential component of all annual meeting activities, and innovative measures of outreach, collaboration, and leadership with the aim of making the CSI a model for improving EDI in other professional research societies.

Effects of empagliflozin on progression of chronic kidney disease: a prespecified secondary analysis from the empa-kidney trial

BACKGROUND

Sodium-glucose co-transporter-2 (SGLT2) inhibitors reduce progression of chronic kidney disease and the risk of cardiovascular morbidity and mortality in a wide range of patients. However, their effects on kidney disease progression in some patients with chronic kidney disease are unclear because few clinical kidney outcomes occurred among such patients in the completed trials. In particular, some guidelines stratify their level of recommendation about who should be treated with SGLT2 inhibitors based on diabetes status and albuminuria. We aimed to assess the effects of empagliflozin on progression of chronic kidney disease both overall and among specific types of participants in the EMPA-KIDNEY trial.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA), and included individuals aged 18 years or older with an estimated glomerular filtration rate (eGFR) of 20 to less than 45 mL/min per 1·73 m2, or with an eGFR of 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher. We explored the effects of 10 mg oral empagliflozin once daily versus placebo on the annualised rate of change in estimated glomerular filtration rate (eGFR slope), a tertiary outcome. We studied the acute slope (from randomisation to 2 months) and chronic slope (from 2 months onwards) separately, using shared parameter models to estimate the latter. Analyses were done in all randomly assigned participants by intention to treat. EMPA-KIDNEY is registered at ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and then followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroups of eGFR included 2282 (34·5%) participants with an eGFR of less than 30 mL/min per 1·73 m2, 2928 (44·3%) with an eGFR of 30 to less than 45 mL/min per 1·73 m2, and 1399 (21·2%) with an eGFR 45 mL/min per 1·73 m2 or higher. Prespecified subgroups of uACR included 1328 (20·1%) with a uACR of less than 30 mg/g, 1864 (28·2%) with a uACR of 30 to 300 mg/g, and 3417 (51·7%) with a uACR of more than 300 mg/g. Overall, allocation to empagliflozin caused an acute 2·12 mL/min per 1·73 m2 (95% CI 1·83-2·41) reduction in eGFR, equivalent to a 6% (5-6) dip in the first 2 months. After this, it halved the chronic slope from -2·75 to -1·37 mL/min per 1·73 m2 per year (relative difference 50%, 95% CI 42-58). The absolute and relative benefits of empagliflozin on the magnitude of the chronic slope varied significantly depending on diabetes status and baseline levels of eGFR and uACR. In particular, the absolute difference in chronic slopes was lower in patients with lower baseline uACR, but because this group progressed more slowly than those with higher uACR, this translated to a larger relative difference in chronic slopes in this group (86% [36-136] reduction in the chronic slope among those with baseline uACR <30 mg/g compared with a 29% [19-38] reduction for those with baseline uACR ≥2000 mg/g; ptrend<0·0001).

INTERPRETATION

Empagliflozin slowed the rate of progression of chronic kidney disease among all types of participant in the EMPA-KIDNEY trial, including those with little albuminuria. Albuminuria alone should not be used to determine whether to treat with an SGLT2 inhibitor.

FUNDING

Boehringer Ingelheim and Eli Lilly.

Impact of primary kidney disease on the effects of empagliflozin in patients with chronic kidney disease: secondary analyses of the EMPA-KIDNEY trial

BACKGROUND

The EMPA-KIDNEY trial showed that empagliflozin reduced the risk of the primary composite outcome of kidney disease progression or cardiovascular death in patients with chronic kidney disease mainly through slowing progression. We aimed to assess how effects of empagliflozin might differ by primary kidney disease across its broad population.

METHODS

EMPA-KIDNEY, a randomised, controlled, phase 3 trial, was conducted at 241 centres in eight countries (Canada, China, Germany, Italy, Japan, Malaysia, the UK, and the USA). Patients were eligible if their estimated glomerular filtration rate (eGFR) was 20 to less than 45 mL/min per 1·73 m2, or 45 to less than 90 mL/min per 1·73 m2 with a urinary albumin-to-creatinine ratio (uACR) of 200 mg/g or higher at screening. They were randomly assigned (1:1) to 10 mg oral empagliflozin once daily or matching placebo. Effects on kidney disease progression (defined as a sustained ≥40% eGFR decline from randomisation, end-stage kidney disease, a sustained eGFR below 10 mL/min per 1·73 m2, or death from kidney failure) were assessed using prespecified Cox models, and eGFR slope analyses used shared parameter models. Subgroup comparisons were performed by including relevant interaction terms in models. EMPA-KIDNEY is registered with ClinicalTrials.gov, NCT03594110.

FINDINGS

Between May 15, 2019, and April 16, 2021, 6609 participants were randomly assigned and followed up for a median of 2·0 years (IQR 1·5-2·4). Prespecified subgroupings by primary kidney disease included 2057 (31·1%) participants with diabetic kidney disease, 1669 (25·3%) with glomerular disease, 1445 (21·9%) with hypertensive or renovascular disease, and 1438 (21·8%) with other or unknown causes. Kidney disease progression occurred in 384 (11·6%) of 3304 patients in the empagliflozin group and 504 (15·2%) of 3305 patients in the placebo group (hazard ratio 0·71 [95% CI 0·62-0·81]), with no evidence that the relative effect size varied significantly by primary kidney disease (pheterogeneity=0·62). The between-group difference in chronic eGFR slopes (ie, from 2 months to final follow-up) was 1·37 mL/min per 1·73 m2 per year (95% CI 1·16-1·59), representing a 50% (42-58) reduction in the rate of chronic eGFR decline. This relative effect of empagliflozin on chronic eGFR slope was similar in analyses by different primary kidney diseases, including in explorations by type of glomerular disease and diabetes (p values for heterogeneity all >0·1).

INTERPRETATION

In a broad range of patients with chronic kidney disease at risk of progression, including a wide range of non-diabetic causes of chronic kidney disease, empagliflozin reduced risk of kidney disease progression. Relative effect sizes were broadly similar irrespective of the cause of primary kidney disease, suggesting that SGLT2 inhibitors should be part of a standard of care to minimise risk of kidney failure in chronic kidney disease.

FUNDING

Boehringer Ingelheim, Eli Lilly, and UK Medical Research Council.

Thrombosis with thrombocytopenia syndrome (TTS) following adenovirus vector COVID-19 vaccination in Canada

INTRODUCTION

Identifying and monitoring adverse events following vaccination contributed to the safety and effectiveness of COVID-19 mass vaccination campaigns. In March 2021, international reports emerged of an adverse event following vaccination with adenovirus vector COVID-19 vaccines (ChAdOx1-S [recombinant] and Ad26.COV2.S) of thrombosis with low platelet counts, referred to as thrombosis with thrombocytopenia syndrome (TTS). We described TTS reports in Canada following adenovirus vector COVID-19 vaccines and investigated whether the observed number of events were higher than expected.

METHODS

Reports of TTS following receipt of ChAdOx1-S [recombinant] or Ad26.COV2.S meeting the Canadian case definition for TTS and diagnostic certainty levels 1-3 of the Brighton Collaboration case definition, submitted to the Canadian Adverse Events Following Immunization Surveillance System and Canada Vigilance Database between February 26, 2021 and October 31, 2022 were included. Demographics and characteristics of the TTS reports are described along with an analysis comparing the observed number of reports to the expected number.

RESULTS

As of October 31, 2022, 56 reports of TTS following administration of ChAdOx1-S [recombinant] and no reports following Ad26.COV2.S vaccines were reported in Canada, of which 37 had functionally positive anti-PF4 antibodies. The median age was 56 years; males accounted for 54 % of reports. Five deaths were reported. The observed number of reports exceeded the expected for all ages and sexes combined, as well as for males aged 30-49 and 60-69 years, and females aged 40-59 years.

CONCLUSION

Based on international surveillance data, Canada evaluated a statistical signal of TTS following adenovirus vector vaccines. The investigation of this signal demonstrated how post-market vaccine safety surveillance systems were successful in investigating rare adverse events during the rollout of COVID-19 vaccines in Canada. As adenovirus vector vaccines continue to be administered, characterization of the association between the vaccine and TTS informs immunization programs and policies.

IL-7 induces type 2 cytokine response in lung ILC2s and regulates GATA3 and CD25 expression

Interleukin-7 is a cytokine with well-established roles in lymphocyte development and more recently, an expanded role in immune function. IL-7Rα is highly expressed by innate lymphoid cells (ILCs), but how IL-7 directs the development or function of ILCs is not well studied. Using mice with inducible deletion of IL-7Rα, we showed that loss of IL-7 signaling led to impaired production of IL-5, IL-13 and amphiregulin in lung ST2⁺ group 2 innate lymphoid cells (ILC2s) following influenza/A infection. Conversely, mice treated with IL-7 increased production of IL-5 and IL-13 by lung ILC2s. Moreover, we showed that IL-7 enhanced GATA3 and CD25 expression in ILC2s and loss of IL-7 signaling led to their reduced expression. Altogether, this study demonstrates that IL-7 regulates the function of ILC2s during airway viral infection and induces GATA3 and CD25 expression.

Low genetic confirmation rate in South Indian subjects with a clinical diagnosis of maturity-onset diabetes of the young (MODY) who underwent targeted next-generation sequencing for 13 genes

PURPOSE

To screen for maturity-onset diabetes of the young (MODY) variants in subjects with an early age of onset and positive family history of diabetes mellitus.

METHODS

60 subjects with onset of diabetes between 3 and 30 years of age and parental history (onset < 35 years) of diabetes were recruited after excluding autoimmune, pancreatic and syndromic forms of diabetes. Detailed pedigree chart and clinical data were recorded. MODY genetic testing (MODY 1-13) was performed and variant classification was done adhering to the ACMG guidelines.

RESULTS

Baseline characteristics of subjects were as follows: mean age of onset of diabetes 19.9 ± 7 years, mean duration of diabetes 6.3 ± 6.8 years, BMI 23.3 ± 3 kg/m² and C-peptide 1.56 ± 1.06 nmol/l. Four out of sixty (6.6%) were positive for variants classifiable as pathogenic/likely pathogenic: one patient with HNF4Ac.691C > T, (p.Arg231Trp), two with HNF 1A c.746C > A(p.Ser249Ter) and c.1340C > T(p.Pro447Leu), and one with ABCC8 c.4544C > T (p.Thr1515Met). MODY 1 and MODY 3 variants were documented in the paediatric age group (< 18 years).

CONCLUSION

A genetic diagnosis of MODY could be confirmed in only 6.6% (4/60) of patients clinically classifiable as MODY. This is less than that reported in clinically diagnosed MODY subjects of European descent. Newly published population data and more stringent criteria for assessment of pathogenicity and younger age of onset of type 2 diabetes in Indians could have contributed to the lower genetic confirmation rate. Apart from variants in the classical genes (HNF1A, HNF4A), a likely pathogenic variant in a non-classical gene (ABCC8) was noted in this study.

In vivo availability of the cytokine IL-7 constrains the survival and homeostasis of peripheral iNKT cells

Understanding the homeostatic mechanism of invariant natural killer T (iNKT) cells is a critical issue in iNKT cell biology. Because interleukin (IL)-15 is required for the thymic generation of iNKT cells, IL-15 has also been considered necessary for the homeostasis of peripheral iNKT cells. Here, we delineated the in vivo cytokine requirement for iNKT cells, and we came to the surprising conclusion that IL-7, not IL-15, is the homeostatic cytokine for iNKT cells. Employing a series of experimental mouse models where the availability of IL-7 or IL-15 was manipulated in peripheral tissues, either by genetic tools or by adult thymectomy and cytokine pump installation, we demonstrate that the abundance of IL-7, and not IL-15, limits the size of the peripheral iNKT cell pool. These results redefine the cytokine requirement for iNKT cells and indicate competition for IL-7 between iNKT and conventional αβ T cells.

Selective dependence on IL-7 for antigen-specific CD8 T cell responses during airway influenza infection

Interleukin-7 (IL-7) is a cytokine known for its importance in T cell development and survival. How IL-7 shapes CD8 T cell responses during an acute viral infection is less understood. We had previously shown that IL-7 signaling deficient mice have reduced accumulation of influenza-specific CD8 T cells following influenza infection. We sought to determine whether IL-7 affects early CD8 T cell expansion in the mediastinal lymph node and effector function in the lungs. Using IL-7Rα signaling deficient mice, we show that IL-7 is required for a normal sized mediastinal lymph node and the early clonal expansion of influenza-specific CD8 T cells therein. We show that IL-7 plays a cell-intrinsic role in the accumulation of NP366-374 and PA224-233-specific CD8 T cells in the lymph node. We also found that IL-7 shapes terminal differentiation, degranulation and cytokine production to a greater extent in PA224-233-specific than NP366-374-specific CD8 T cells. We further demonstrate that IL-7 is induced in the lung tissue by viral infection and we characterize multiple cellular sources that contribute to IL-7 production. Our findings on IL-7 and its effects on lower respiratory diseases will be important for expanding the utility of therapeutics that are currently available.

CCL5 production in lung cancer cells leads to an altered immune microenvironment and promotes tumor development

Current immunotherapies for lung cancer are only effective in a subset of patients. Identifying tumor-derived factors that facilitate immunosuppression offers the opportunity to develop novel strategies to supplement and improve current therapeutics. We sought to determine whether expression of driver oncogenes in lung cancer cells affects cytokine secretion, alters the local immune environment, and influences lung tumor progression. We demonstrate that oncogenic EGFR and KRAS mutations, which are early events in lung tumourigenesis, can drive cytokine and chemokine production by cancer cells. One of the most prominent changes was in CCL5, which was rapidly induced by KRAS^G12V or EGFR^L858R expression, through MAPK activation. Immunocompetent mice implanted with syngeneic KRAS-mutant lung cancer cells deficient in CCL5 have decreased regulatory T cells (T_regs), evidence of T cell exhaustion, and reduced lung tumor burden, indicating tumor-cell CCL5 production contributes to an immune suppressive environment in the lungs. Furthermore, high CCL5 expression correlates with poor prognosis, immunosuppressive regulatory T cells, and alteration to CD8 effector function in lung adenocarcinoma patients. Our data support targeting CCL5 or CCL5 receptors on immune suppressive cells to prevent formation of an immune suppressive tumor microenvironment that promotes lung cancer progression and immunotherapy insensitivity.

Transcriptional regulation of type 2 innate lymphoid cells and precursors by interleukin-7 receptor signalling

Innate lymphoid cells (ILCs) are a rare population of innate immune cells that act as the first line of defense against pathogens. These cells arise from the lymphoid lineage that B and T cells also belong to. Type 2 ILCs (ILC2s) are a subset of ILCs that reside in the lungs, mucosal layers, and skin, and have roles in clearing helminth infections, triggering allergic responses, and promoting lung tissue repair after influenza infections. The functions of ILC2s mirror those of TH2 cells but lack antigen recognition. However, their full development background is still unknown. It is believed that ILC2s develop in the fetal liver and adult bone marrow from common lymphoid progenitors and differentiate into several intermediates including helper ILC precursors. From this, ILC2 progenitors arise and express interleukin-7 (IL-7) receptor with the aid of the transcription factor GATA3. Our lab has found that IL-7 is critical for ILC2 development as mutations to the IL-7 receptor show a reduction in the ILC2 numbers and GATA3 expression. Conversely, overexpression of IL-7 results in the expansion of ILC2s and elevated GATA3 expression. We hypothesize that IL-7 signalling dictates ILC2 development through the transcriptional regulation of lineage determining factors. We aim to identify the transcriptional and epigenetic landscape regulated by IL-7 in ILC2s and their progenitors using single cell RNA sequencing and chromatin immunoprecipitation sequencing. We will also investigate how IL-7 influences airway immune responses generated by ILC2s using flow cytometry and RNA sequencing. This study will increase our understanding of a vital cell population and contribute to the development of therapeutics for allergic asthma and viral infections.

The Role of CD4+ Tissue Resident Memory Cells in Oncogene Driven Lung Adenocarcinoma

Lung cancer presents a global health risk that is responsible for over 2 million deaths worldwide every year. Tissue resident memory T cells (Trm) are critical for rapid protection to pathogens at entry points in the body, including the lung. Trm are identified as CD69+ CD103+ cells which remain in the tissue (i.e. lung), are longer-lived memory cells, and have antigen specificity. Many studies have shown clinical significance with tumour infiltrating lymphocytes (TIL) markers of CD103+ and CD69+ in solid tumour cancers. Few studies have addressed the direct or indirect mechanism of anti-tumour function of CD4+ Trm cells during tumour progression and how the tumour microenvironment impacts this. One primary role of CD4+ T cells in anti-tumour immunity is to provide aid to CD8+ effector cells. CD4+ Trm are known to have Th1 interferon responses to viral infection and Th2 type responses in allergic response leading to excess fibrosis. Little is known of the diversity of CD4+ Trm and their Type-1 or -2 phenotypes during cancer. In this study, we used a genetically engineered mouse model (GEMM) of lung adenocarcinoma (LAC), with doxycycline-inducible oncogene mutation KRASG12D. We observed a significant increase in PD-1+ CD4+ Trm with a Th2-like phenotype (CD44+ CD62L−CD103+ CD69+ PD-1+GATA3hi) in the KRASG12D tumour bearing lungs. When stimulated ex vivo with PMA/ionomycin, we found CD4+ CD69+ cells produced more IFNγ in the KRASG12DGEMM. To examine clinical relevance, we used the program KMplotter and found signatures of Trm and CD4+ Trm significantly correlated with increased survival in LAC patients. We intend to determine the functional relevance of these Th2-like CD4+ TRM cells in the tumour microenvironment.

Knowledge, Attitude and Practice on Covid-19 among Clinical Healthcare Workers in Bingham University Teaching Hospital (BHUTH) Jos, Plateau State, Nigeria

BACKGROUND

The ongoing Covid-19 pandemic is now a global health emergency with significant morbidity and mortality among different populations of the world. Healthcare professionals are the people in the front line of situations like this. Their perspectives on the pandemic is critical to their safety and the outcomes in patients they manage. The aim of this study is to assess the knowledge, attitude and practice regarding COVID-19 among clinical healthcare professionals in Bingham University Teaching Hospital (BHUTH) Jos.

MATERIALS AND METHODS

A total of 138 clinical health workers from BHUTH completed a questionnaire- based study on the knowledge, attitude and practice on COVID-19 from the April 1st to 30th May 2020. Consecutive sampling method was used for data collection and the distribution of responses was presented as frequencies and percentages. Analysis of Variance (ANOVA) test was used to investigate the level of association among variables at the significance level of p<0.05.

RESULTS

The highest mean of correct responses for knowledge were from doctors, pharmacists and nurses with 19.1±2.35, 19.4±1.52 and 18.9±1.73 respectively. The lowest mean was from pharmacist assistant and nurse aids with 17.1±1.81. The difference was statistically significant with Anaysis of Variance (F) of 5.75 and p value of 0.001. The attitude and practice mean were good between the different clinical cadre; however, the difference was not significant.

CONCLUSION

There is good knowledge, attitude and practice among the doctors and pharmacists, nurses, nurse assistants and pharmacist assistants. The doctors and pharmacist had better scores. There is the need for regular training and update.

Assessment of long non-coding RNA expression reveals novel mediators of the lung tumour immune response

The tumour immune microenvironment is a crucial mediator of lung tumourigenesis, and characterizing the immune landscape of patient tumours may guide immunotherapy treatment regimens and uncover novel intervention points. We sought to identify the landscape of tumour-infiltrating immune cells in the context of long non-coding RNA (lncRNAs), known regulators of gene expression. We examined the lncRNA profiles of lung adenocarcinoma (LUAD) tumours by interrogating RNA sequencing data from microdissected and non-microdissected samples (BCCRC and TCGA). Subsequently, analysis of single-cell RNA sequencing data from lung tumours and flow-sorted healthy peripheral blood mononuclear cells identified lncRNAs in immune cells, highlighting their biological and prognostic relevance. We discovered lncRNA expression patterns indicative of regulatory relationships with immune-related protein-coding genes, including the relationship between AC008750.1 and NKG7 in NK cells. Activation of NK cells in vitro was sufficient to induce AC008750.1 expression. Finally, siRNA-mediated knockdown of AC008750.1 significantly impaired both the expression of NKG7 and the anti-tumour capacity of NK cells. We present an atlas of cancer-cell extrinsic immune cell-expressed lncRNAs, in vitro evidence for a functional role of lncRNAs in anti-tumour immune activity, which upon further exploration may reveal novel clinical utility as markers of immune infiltration.

IL-7 shapes a multifaceted CD8 T cell response to airway Influenza/A infection

The lungs are a site vulnerable to diseases such as cancer, autoimmunity and infections. With each breath, we risk inhaling infectious agents, and as such, airborne diseases are the leading cause of infectious disease-related deaths in the world. In particular, various strains of Influenza virus can infect airway epithelial cells and activate a network of immune cells leading to clearance, or in cases of pandemic strains, an overzealous response that can be fatal.

Adaptive immune cells, particularly cytotoxic CD8 T cell lymphocytes, play a crucial role in controlling viral replication by killing infected cells. Therefore, tight regulation of the cytokines that lead to the proper activation, proliferation and function of these immune cells is necessary to clear infections efficiently while minimizing damage to the host. Interleukin-7 (IL-7) is a cytokine known for its importance in T cell development and survival. While the function of IL-7 in T cell survival is well characterized, how IL-7 shapes T cell effector responses when a pathogen is encountered is less understood.

Using IL-7Rα hypomorph mice in chimeric and adoptive transfer experiments we have found that IL-7 is cell-intrinsically important for the priming of antigen specific CD8 T cells in the draining lymph nodes. We found that IL-7 dictates terminal differentiation, cytokine production and degranulation of CD8 T cells locally in the airways. Drugs that manipulate IL-7 signaling are currently under clinical trial for multiple conditions. Our findings on IL-7 and its effects on lower respiratory diseases will be necessary for expanding the utility of these therapeutics.

Tumor intrinsic mechanisms of immunosuppression in CD8 T cell function and response to lung cancer

Immunotherapies are effective in a subset of patients with non-small cell lung cancer (NSCLC), however the majority do not respond which highlights the ongoing need for novel therapeutics and biomarkers. Tumor cells can produce cytokines and chemokines that influence both the recruitment and function of immune cells. In patients with NSCLC, the microRNA-17~92 (miR-17~92) cluster was shown to be upregulated, and high levels of microRNA-17 in serum was associated with decreased survival. We aimed to identify whether tumor cell intrinsic mechanisms, like upregulation of miR-17~92, regulate chemokine or cytokine production to induce an immunosuppressive tumor microenvironment and inhibit CD8+ T cell anti-tumor function in the lung. We used the CIBERSORTX program to evaluate alterations to immune cell populations and survival in NSCLC patients with increased chemokine or miR-17~92 expression. We found high expression of miR-17 and low expression of IL-7Rα correlated with decreased survival in lung adenocarcinoma (LAC) patients. Furthermore, LAC patient’s tumor biopsies with high miR-17 had decreased IL-7Rα and increased populations of CD8+ T cells by CIBERSORTX. We will use in vitro and in vivo models of lung cancer to determine whether miR-17~92 upregulation and tumor cell chemokines and cytokines production drives immunosuppression in the tumor microenvironment. Understanding how lung tumor cells regulate cytokines and chemokines, and their putative control of exhaustion in CD8 T cells in the tumor microenvironment would guide selection of efficacious immunotherapy treatment.

Abstract A38: Oncogenes drive production of immunosuppressive cytokines to facilitate lung cancer progression

Lung cancer development is driven by the expression of mutant oncogenes, with EGFR and KRAS being the most frequent mutations in lung adenocarcinoma. However, these mutations alone are not sufficient for tumorigenesis, and additional factors influence tumor development and progression, including the balance of antitumor immune effector cells and protumorigenic immune suppressor cells within the tumor environment. We hypothesized that oncogene signaling regulates the production of cytokines by tumor cells in order to modulate the immune microenviroment and promote lung tumor development. We used CIBERSORT to quantify 22 immune cell types in over 300 human lung adenocarcinomas (LUAD) and 100 matched normal lung tissues. Cells associated with inflammatory or antitumor response, macrophages (M1, M0), T follicular helper cells, and plasma cells, were enriched in LUAD compared to normal lung tissue. Additionally, immunosuppressive regulatory T cells (Tregs) were significantly enriched in LUAD tumors, even at the early stages. To identify cytokines that could be induced by oncogenic signaling early in lung tumorigenesis, we used normal cells expressing doxycycline-inducible mutant KRASG12V mutant EGFRL858R or wild-type EGFR and analyzed cytokine production with a multiplex assay (LUMINEX). Induction of oncogenic signaling in normal cells rapidly increased production of cytokines CCL5 and CCL2. These are capable of recruiting a variety of cells types, including Tregs. In KRAS mutant lung cancer cells, disruption of oncogene signaling with a MEK inhibitor (trametinib) decreased CCL5 production. We used transgenic mice that spontaneously develop lung tumors in response to tetracycline-inducible expression of mutant EGFRDelEx19 or mutant KRASG12V in type II alveolar cells to investigate immune cell populations that may change in response to oncogene-driven lung tumorigenesis. We found that Tregs were increased in the lungs of tumor-bearing mice. These Tregs express the CCL5 receptor, CCR5. Several cytokines were elevated in bronchioalveolar lavage fluid or in lung lysates of tumor-bearing mice, including IL-12(p40), CXCL1, CCL2, CCL3 and CCL5. Murine Lewis lung carcinoma (LLC) cells harbor a KRAS mutation and express high levels of CCL5. We are currently investigating the effects of disrupting oncogene signaling or CCL5 expression in LLC cells on cytokine production and immune cell recruitment in vivo using syngeneic implantation of the cells into mice. Our data suggest that oncogenic signaling regulates expression of cytokines in lung tumor cells. Targeted inhibition of cytokines directly or indirectly through oncogenic signaling may represent therapeutic strategies to block the recruitment of immune-suppressive cells to the tumor microenvironment, thereby enhancing the antitumor immune response.

Citation Format: Elizabeth Franks, Etienne Melese, Bryant Harbourne, Liz Halvorsen, Rachel Cederberg, Jenna Collier, Natalie Firmino, Jennifer Luu, Arun Unni, Min Hee Oh, Vivian Lam, Gerry Krystal, Ninan Abraham, Kevin Bennewith, William Lockwood. Oncogenes drive production of immunosuppressive cytokines to facilitate lung cancer progression [abstract]. In: Proceedings of the AACR Special Conference on Tumor Immunology and Immunotherapy; 2018 Nov 27-30; Miami Beach, FL. Philadelphia (PA): AACR; Cancer Immunol Res 2020;8(4 Suppl):Abstract nr A38.

Interleukin-7 Receptor Alpha in Innate Lymphoid Cells: More Than a Marker

Innate lymphoid cells (ILCs) are a group of immune cells that are important for defense against pathogens, tissue repair, and lymphoid organogenesis. They share similar characteristics with various subsets of helper T cells but lack specific antigen receptors. Interleukin-7 (IL-7) and thymic stromal lymphopoietin (TSLP) are cytokines that engage the IL-7Rα and have major roles in dictating the fate of ILCs. Recent advances in the field have revealed transcriptional programs associated with ILC development and function. In this article, we will review recent studies of the role of IL-7 and TSLP in ILC development and function during infection and inflammation.

Estimating the magnitude of pulmonary tuberculosis patients missed by primary health care clinics in South Africa

SETTING

The present study was conducted at 20 randomly selected primary health clinics across Buffalo City Metropolitan Health District, a high TB burden district in South Africa.

OBJECTIVE

To estimate the proportion of TB patients missed by primary health clinics.

DESIGN

We enrolled 1255 TB-symptomatic individuals exiting primary health clinics between March and December 2015. Participants were interviewed and asked to provide sputum for Xpert® MTB/RIF testing.

RESULTS

Clinic staff screened 79.1% of participants seeking care for TB-related symptoms and 21.9% of those attending a clinic for other reasons (P < 0.001). Of those screened by clinic staff, 21.5% reported submitting sputum, although only 9.8% had available results. Study staff tested sputum from 779 participants not tested by clinic staff. Of these, 39 (5.0%) individuals tested positive for TB, three of whom were rifampicin-resistant; 15/39 (38.5%) were never screened and 24/39 (61.5%) were screened but not tested by clinic staff. We estimate that the health system missed 62.9-78.5% of TB patients attending primary health clinics for TB-related symptoms and 89.5-100% of those attending a clinic for other reasons.

CONCLUSION

Low rates of TB screening and testing by the health system resulted in missed TB patients. Universal TB screening and testing of symptomatic individuals should be instituted in high TB burden communities in South Africa.

Somatic mutation-associated T follicular helper cell elevation in lung adenocarcinoma

T follicular helper cells (Tfh) play crucial roles in the development of humoral immunity. In the B cell-rich germinal center of lymphoid organs, they select for high-affinity B cells and aid in their maturation. While Tfh have known roles in B cell malignancies and have prognostic value in some epithelial cancers, their role in lung tumour initiation and development is unknown. Through immune cell deconvolution, we observed significantly increased Tfh in tumours from two independent cohorts of lung adenocarcinomas and found that this upregulation occurs early in tumour development. A subset of tumours were stained for T and B cells using multicolour immunohistochemistry, which revealed the presence of tumour-adjacent tertiary lymphoid organs in 17/20 cases each with an average of 16 Tfh observed in the germinal center. Importantly, Tfh levels were correlated with tumour mutational load and immunogenic cancer testis antigens, suggesting their involvement in mounting an active immune response against tumour neoantigens.

Abstract A02: Oncogenic drivers of lung cancer induce production of CCL5 and recruitment of regulatory T-cells

Lung cancer development is driven by the expression of mutant oncogenes, with EGFR and KRAS being the most frequent mutations in lung adenocarcinoma. However, additional factors may influence lung tumor development and progression, including the balance of antitumor immune effector cells and pro-tumorigenic immune suppressor cells within the lung and lung tumor microenvironment. Tumor cells can evade immune attack by producing cytokines that recruit immune modulatory cells, such as regulatory T cells (Tregs), that promote a localized immune suppressive environment We hypothesized that oncogene signaling regulates the production of cytokines by tumor cells at the earliest stages of transformation that can recruit immune suppressive cells and promote lung tumour development. We used CIBERSORT-based analysis of gene expression data to quantify 22 different immune cell types from over 300 human lung adenocarcinomas and 100 matched normal lung tissues. We found that Tregs were significantly enriched in early-stage lung adenocarcinoma tumors compared to matched normal tissue from the same patient, and validated these findings with immunohistochemistry staining of lung sections. To identify cytokines that could recruit Tregs early in lung tumorigenesis, we used normal cells expressing doxycycline-inducible wild-type EGFR, mutant EGFRL858R or mutant KRASG12V. Secreted cytokines were quantified using a multiplex LUMINEX assay with subsequent validation by ELISA. Induction of EGFRL858R and KRASG12V expression in normal cells rapidly increased the production of CCL5 (RANTES), as did expression of wild-type EGFR in the presence of exogenous EGF. To elucidate the mechanism of oncogene-driven CCL5 secretion, we treated lung cancer cells harboring EGFR or KRAS mutations with a MEK inhibitor (trametinib) to disrupt oncogenic signaling downstream of EGFR and KRAS. In KRAS mutant lung cancer cells, treatment with trametinib decreased CCL5 production and inhibited both ERK and AKT signaling. To determine if oncogene-driven cytokines could induce migration of Tregs ex vivo, we used a trans-well assay with conditioned media from cells expressing doxycycline inducible EGFRL858R or KRASG12V. Conditioned media from EGFRL858R and KRASG12V-expressing cells induced Treg migration, which was mitigated by the addition of an anti-CCL5 antibody. These data indicate that oncogenic EGFR and KRAS signaling regulates expression of CCL5 in lung tumor cells, and that CCL5-mediated Treg recruitment to lung tumors may occur in early stages of lung tumor development. Therefore, targeted inhibition of CCL5, Tregs, and/or oncogenic EGFR and KRAS signaling may represent therapeutic strategies to block recruitment and function of immunosuppressive Tregs during lung tumor development.

Citation Format: Elizabeth Franks, Elizabeth C. Halvorsen, Etienne Melese, Unni Arun, Jenna L. Collier, Bryant T. Harbourne, Min Hee Oh, Lam Vivian, Gerry Krystal, John C. English, Wan L. Lam, Stephen Lam, Ninan Abraham, Kevin L. Bennewith, William W. Lockwood. Oncogenic drivers of lung cancer induce production of CCL5 and recruitment of regulatory T-cells [abstract]. In: Proceedings of the Fifth AACR-IASLC International Joint Conference: Lung Cancer Translational Science from the Bench to the Clinic; Jan 8-11, 2018; San Diego, CA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(17_Suppl):Abstract nr A02.

Paracrine rather than systemic glucocorticoids are biologically active in the thymus

Thymocyte positive and negative selection are critical for generation of a competent and self-tolerant T cell repertoire. Glucocorticoids (GCs) protect thymocytes from T cell receptor (TCR)-induced death, and thymocyte-specific GC receptor (GR) deletion amplifies negative selection, weakening the TCR repertoire. Circulating GCs are secreted by the adrenals, but levels fluctuate widely with time of day and in response to stressors. To avoid such variation, thymus GCs might be regulated independently of the adrenals, as thymic epithelial cells (TECs) and possibly thymocytes express GC-synthetic enzymes. Whether local GC production is sufficient to affect thymocyte development in the presence of adrenal GCs, however, is unknown. Here, we have found that corticosterone, the major mouse GC, was locally elevated in the thymus compared to the blood, and that cultured thymus produced corticosterone from endogenous substrates via GC-synthetic enzyme activity. To test the source and importance of local GC synthesis in vivo, we generated mice with targeted deletion of the GC-synthetic enzyme Cyp11b1 in TECs (Cyp11b1foxn1-Cre) or thymocytes (Cyp11b1lck-Cre). As a measure of GC signaling we quantified thymocyte expression of the GC-responsive gene Gilz. Gilz mRNA was normal in Cyp11b1lck-Cre but reduced in Cyp11b1foxn1-Cre thymocytes, with a reduction equivalent to that in GR-deficient thymocytes. Basal GR signaling is thus driven overwhelmingly by TEC-rather than adrenal-derived corticosterone. These findings demonstrate the importance of paracrine GC function in vivo, and are consistent with a role for paracrine GCs in thymocyte selection.

Emerging roles of T helper 17 and regulatory T cells in lung cancer progression and metastasis

Lung cancer is a leading cause of cancer-related deaths worldwide. Lung cancer risk factors, including smoking and exposure to environmental carcinogens, have been linked to chronic inflammation. An integral feature of inflammation is the activation, expansion and infiltration of diverse immune cell types, including CD4⁺ T cells. Within this T cell subset are immunosuppressive regulatory T (Treg) cells and pro-inflammatory T helper 17 (Th17) cells that act in a fine balance to regulate appropriate adaptive immune responses.In the context of lung cancer, evidence suggests that Tregs promote metastasis and metastatic tumor foci development. Additionally, Th17 cells have been shown to be an integral component of the inflammatory milieu in the tumor microenvironment, and potentially involved in promoting distinct lung tumor phenotypes. Studies have shown that the composition of Tregs and Th17 cells are altered in the tumor microenvironment, and that these two CD4⁺ T cell subsets play active roles in promoting lung cancer progression and metastasis.We review current knowledge on the influence of Treg and Th17 cells on lung cancer tumorigenesis, progression, metastasis and prognosis. Furthermore, we discuss the potential biological and clinical implications of the balance among Treg/Th17 cells in the context of the lung tumor microenvironment and highlight the potential prognostic function and relationship to metastasis in lung cancer.

Lymphoid organs of neonatal and adult mice preferentially produce active glucocorticoids from metabolites, not precursors

Glucocorticoids (GCs) are circulating adrenal steroid hormones that coordinate physiology, especially the counter-regulatory response to stressors. While systemic GCs are often considered immunosuppressive, GCs in the thymus play a critical role in antigen-specific immunity by ensuring the selection of competent T cells. Elevated thymus-specific GC levels are thought to occur by local synthesis, but the mechanism of such tissue-specific GC production remains unknown. Here, we found metyrapone-blockable GC production in neonatal and adult bone marrow, spleen, and thymus of C57BL/6 mice. This production was primarily via regeneration of adrenal metabolites, rather than de novo synthesis from cholesterol, as we found high levels of gene expression and activity of the GC-regenerating enzyme 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1), but not the GC-synthetic enzyme CYP11B1. Furthermore, incubation with physiological concentrations of GC metabolites (11-dehydrocorticosterone, prednisone) induced 11β-HSD1- and GC receptor-dependent apoptosis (caspase activation) in both T and B cells, showing the functional relevance of local GC regeneration in lymphocyte GC signaling. Local GC production in bone marrow and spleen raises the possibility that GCs play a key role in B cell selection similar to their role in T cell selection. Our results also indicate that local GC production may amplify changes in adrenal GC signaling, rather than buffering against such changes, in the immune system.

Topical CpG Oligodeoxynucleotide Adjuvant Enhances the Adaptive Immune Response against Influenza A Infections

Current influenza vaccines generate humoral immunity, targeting highly variable epitopes and thus fail to achieve long-term protection. T cells recognize and respond to several highly conserved epitopes across influenza serotypes. A strategy of raising strong cytotoxic T cell memory responses to epitopes conserved across serotypes would provide cross serotype protection, eliminating the need for annual vaccination. We explored the adjuvant potential of epicutaneous (ec) and subcutaneous (sc) delivery of CpG oligodeoxynucleotide in conjunction with sc protein immunization to improve protection against influenza A virus (IAV) infections using a mouse model. We found enhanced long-term protection with epicutaneous CpG ODN (ecCpG) compared to subcutaneous CpG ODN (scCpG) as demonstrated by reduced viral titers in the lungs. This correlated with increased antigen-specific CD8 T cells in the airways and the lungs. The memory T cell response after immunization with ecCpG adjuvant was comparable to memory response by priming with IAV infection in the lungs. In addition, ecCpG was more efficient than scCpG in inducing the generation of IFN-γ producing CD4 T cells. The adjuvant effect of ecCpG was accompanied with its ability to modulate tissue-homing molecules on T cells that may direct them to the site of infection. Together, this work provides evidence for using ecCpG to induce strong antibody and memory T cell responses to confer protection against IAV infection.

‘Innate and T lymphocyte developmental pathways independent of Common lymphoid progenitors’

Lymphocytes are believed to develop from a population of committed lymphoid progenitors termed common lymphoid progenitors (CLPs). However, upstream lymphoid progenitors termed lymphoid-primed multi-potent progenitors (LMPPs) are more efficient than CLPs in differentiating into group 2 innate lymphoid cells (ILC2s) and T cells, suggesting that alternative pathways for the development of these cells exist. In this study, we divided LMPPs into CD127− (LMPP-s) and CD127+ (LMPP+s) subsets and compared them with Ly6D+ and Ly6D− CLPs. Adult LMPP+s differentiated into ILCs and T cells more rapidly and efficiently than other progenitors in transplantation assays. Development of ILC2s and T cells is highly active during neonatal period. In this period CLPs are rare and, unlike prominent neonatal LMPP+s, do not efficiently differentiate into ILC2s and T cells. ILC2s generated in neonates persist in adults. These results suggest that the majority of ILCs and T cells develop from LMPP+s via CLP-independent pathways.

Common-Lymphoid-Progenitor-Independent Pathways of Innate and T Lymphocyte Development

All lymphocytes are thought to develop from common lymphoid progenitors (CLPs). However, lymphoid-primed multipotent progenitors (LMPPs) are more efficient than CLPs in differentiating into T cells and group 2 innate lymphoid cells (ILC2s). Here, we have divided LMPPs into CD127(-) (LMPP-s) and CD127(+) (LMPP+s) subsets and compared them with Ly6D(-) and Ly6D(+) CLPs. Adult LMPP+s differentiated into T cells and ILCs more rapidly and efficiently than other progenitors in transplantation assays. The development of T cells and ILC2s is highly active in the neonatal period. Neonatal CLPs are rare and, unlike prominent neonatal LMPP+s, do not efficiently differentiate into T cells and ILC2s. ILC2s generated in the neonatal period are long lived and persist in adult tissues. These results suggest that some ILCs and T cells may develop from LMPP+s via CLP-independent pathways.

Survival of effector CD8+ T cells during influenza infection is dependent on autophagy

The activation and expansion of effector CD8(+) T cells are essential for controlling viral infections and tumor surveillance. During an immune response, T cells encounter extrinsic and intrinsic factors, including oxidative stress, nutrient availability, and inflammation, that can modulate their capacity to activate, proliferate, and survive. The dependency of T cells on autophagy for in vitro and in vivo activation, expansion, and memory remains unclear. Moreover, the specific signals and mechanisms that activate autophagy in T effector cells and their survival are not known. In this study, we generated a novel inducible autophagy knockout mouse to study T cell effector responses during the course of a virus infection. In response to influenza infection, Atg5(-/-) CD8(+) T cells had a decreased capacity to reach the peak effector response and were unable to maintain cell viability during the effector phase. As a consequence of Atg5 deletion and the impairment in effector-to-memory cell survival, mice fail to mount a memory response following a secondary challenge. We found that Atg5(-/-) effector CD8(+) T cells upregulated p53, a transcriptional state that was concomitant with widespread hypoxia in lymphoid tissues of infected mice. The onset of p53 activation was concurrent with higher levels of reactive oxygen species (ROS) that resulted in ROS-dependent apoptotic cell death, a fate that could be rescued by treating with the ROS scavenger N-acetylcysteine. Collectively, these results demonstrate that effector CD8(+) T cells require autophagy to suppress cell death and maintain survival in response to a viral infection.

Steroid profiling reveals widespread local regulation of glucocorticoid levels during mouse development

Glucocorticoids (GCs) are produced by the adrenal glands and circulate in the blood to coordinate organismal physiology. In addition, different tissues may independently regulate their local GC levels via local GC synthesis. Here, we find that in the mouse, endogenous GCs show tissue-specific developmental patterns, rather than mirroring GCs in the blood. Using solid-phase extraction, HPLC, and specific immunoassays, we quantified endogenous steroids and found that in tissues of female and male mice, (1) local GC levels can be much higher than systemic GC levels, (2) local GCs follow age-related patterns different from those of systemic GCs, and (3) local GCs have identities different from those of systemic GCs. For example, whereas corticosterone is the predominant circulating adrenal GC in mice, high concentrations of cortisol were measured in neonatal thymus, bone marrow, and heart. The presence of cortisol was confirmed with liquid chromatography-tandem mass spectrometry. In addition, gene expression of steroidogenic enzymes was detected across multiple tissues, consistent with local GC production. Our results demonstrate that local GCs can differ from GCs in circulating blood. This finding suggests that steroids are widely used as local (paracrine or autocrine) signals, in addition to their classic role as systemic (endocrine) signals. Local GC regulation may even be the norm, rather than the exception, especially during development.

The survival and differentiation of pro-B and pre-B cells in the bone marrow is dependent on IL-7Rα Tyr449

IL-7 is critical for murine T and B cell development and survival and plays a significant role in lymphoblastic leukemia in both humans and mice. We evaluated the role of the IL-7Rα Tyr(449) cytoplasmic SH2-binding motif in IL-7-mediated B cell development using a knock-in mouse with a Tyr to Phe mutation (IL-7Rα(449F/449F) mouse). IL-7Rα(449F/449F) and IL-7Rα(-/-) mice showed no defect in the number of pre-pro-B cells, although IL-7Rα(449F/449F) mice had decreased Ebf1 in pre-pro-B cells and impairment in B cell-committed CLPs. We identified that IL-7Rα Tyr(449) was critical for both pro-B and pre-B stages of development in the bone marrow. IL-7Rα(449F/449F) and IL-7Rα(-/-) mice had comparable precursor B cell defects, indicating that signaling from the IL-7Rα required this motif. Although the defect in IL-7Rα(449F/449F) pro-B cells was associated with loss of STAT5 activation and diminished expression of Mcl1, this was not rescued by overexpression of Bcl-2. IL-7Rα(449F/449F) and IL-7Rα(-/-) pre-B cells also showed defective cyto-Igμ and CD25 expression, associated with reduced levels of Rag1, Rag2, and Irf4. Pre-B cells from IL-7Rα(449F/449F) mice also failed to proliferate, perhaps as a result of the failure to rearrange Igμ. Our data suggest that IL-7Rα Tyr(449) was essential for IL-7Rα signaling in bone marrow B cell development and survival.

The development and survival but not function of follicular B cells is dependent on IL-7Rα Tyr449 signaling. (CCR1P.242)

IL-7 is a critical cytokine for lymphocyte development but its role in B cells is less well characterized. Using a knock-in mouse with a Tyr to Phe mutation at position 449 (IL-7Rα449F/449F mice) within the cytoplasmic domain of IL-7Rα, we evaluated the role of this YxxM motif in spleen B cells. IL-7Rα449F/449F mice had reduced numbers and increased death of follicular B cells compared to WT, but had significantly more follicular cells than IL-7Rα-/-. The death of IL-7Rα449F/449F follicular cells was not due to a failure to respond to BAFF or lower levels of BAFF. Marginal zone B cells were unaffected in IL-7Rα449F/449F mice. A role for TSLP was ruled out, as TSLPR-/- mice had an identical B cell phenotype to wild-type mice. Bone marrow chimeras and the absence of IL-7Rα on B cells suggested that IL-7 did not directly regulate mature B cells, but that an IL-7-responsive cell was influencing B cells. IL-7 was also critical at the checkpoint between the T1 and T2 stages in the spleen. We tested the functional responses of IL-7Rα449F/449F mice and found no difference in antibody responses to T-dependent or T-independent antigens, or to Influenza/A. IL-7 was important for generation of antibody responses to the intestinal worm H. polygyrus and for naive levels of IgA. Our data shows that IL-7 regulates follicular B cell numbers and survival in a cell-extrinsic manner, via a bone-marrow derived cell, but is not critical for antibody production outside the gut.

The development and survival but not function of follicular B cells is dependent on IL-7Rα Tyr449 signaling

IL-7 is a critical cytokine for lymphocyte development. Recent work has highlighted critical roles for IL-7 signaling in mature T cell homeostasis and function, but its role in B cells is less well characterized. Using a knock-in mouse possessing a Tyr to Phe mutation at position 449 (IL-7Rα(449F/449F) mice) within the cytoplasmic SH2-binding motif of IL-7Rα, we evaluated the role of IL-7Rα Y449 motif in spleen B cells. IL-7Rα(449F/449F) mice had reduced numbers and increased death of follicular B cells compared to WT, but had significantly more follicular cells than IL-7Rα(-/-). The death of IL-7Rα(449F/449F) follicular cells was not due to a failure to respond to BAFF or lower levels of BAFF, a critical B cell survival factor. Marginal zone B cells were unaffected by the IL-7Rα(449F/449F) mutation. Any role for TSLP was ruled out, as TSLPR(-/-) mice had an identical B cell phenotype to wild-type mice. Bone marrow chimeras and the absence of IL-7Rα on B cells suggested that IL-7 did not directly regulate mature B cells, but that an IL-7-responsive cell was influencing B cells. IL-7 was also critical at the checkpoint between the T1 and T2 stages in the spleen. IL-7Rα(-/-) mice fail to develop T2 cells, but IL-7Rα(449F/449F) show a reduction compared to WT but not complete absence of T2 cells. We also tested the functional responses of IL-7Rα(449F/449F) to antigens and infection and found no difference in antibody responses to T-dependent or T-independent antigens, or to Influenza/A. IL-7 was important for generation of antibody responses to the intestinal worm H. polygyrus and for naive levels of IgA. Taken together, this suggests that IL-7 regulates follicular B cell numbers and survival in a cell-extrinsic manner, via a bone-marrow derived cell, but is not critical for antibody production outside the gut.

Topical CpG adjuvant enhances immune response to subcutaneous antigen by modulating the cutaneous lymph node environment (P4267)

Current vaccines are mainly administered by intramuscular route but the skin harbors many immune cells and can be used as a site of immunization. Topical CpG oligodeoxynucleotide (ODN), a Toll-like receptor 9 (TLR9) agonist, improves humoral and cell-mediated immune responses to locally injected protein-based vaccines in mice but the mechanisms are still unclear. Topical CpG ODN is internalized by CD11c+ cells that are detected within the skin draining lymph nodes (SLN) at 48 hours post treatment. Ablation of TLR9 in the hematopoietic compartment of bone marrow chimeric mice abrogates antigen-specific CD8+ T cells production. TLR9 ablation in the stromal compartment also decreases topical CpG adjuvant effect. Topical CpG ODN differentially modulates the environment of SLN compared to subcutaneous administration within 24 hours of treatment (with 4-7 fold increased expression of 4 genes: Ccl4, Cxcl3, Ifng and Il11). A higher proportion of antigen-specific CD4+ T cells in the SLN express tissue-homing molecules (P- and E-selectin ligand) when adjuvant is administered topically compared to subcutaneously. Egress of lymphocytes from SLN is necessary for optimal CpG adjuvant effect using a contact hypersensitivity model. We propose that topical CpG ODN activates stromal cells as well as hematopoietic-derived cells in the skin, to subsequently modulate the environment of SLN. These changes enhance protective humoral and cell-mediated immune responses.

Surgical techniques for pelvic floor reconstruction: review of the recent literature

The number of women who will undergo pelvic organ prolapse repair is predicted to increase by almost 50% by 2050. Surgeons need updated knowledge and mastery of pelvic floor reconstruction in order to meet the rising demand for services. This review provides an update on the evidence for the various surgical techniques for anterior, posterior, and apical pelvic organ prolapse, specifically focusing on randomized trials within the last ten years.

Interleukin-7, but not thymic stromal lymphopoietin, plays a key role in the T cell response to influenza A virus

The immune response to viral infection is ideally rapid and specific, resulting in viral clearance and establishment of immune memory. Some viruses such as HIV can evade such responses leading to chronic infection, while others like Influenza A can elicit a severe inflammatory response with immune-related complications including death. Cytokines play a major role in shaping the appropriate outcomes to infection. While Interleukin-7 (IL-7) has a critical role in T and B cell development, treatment with IL-7 has recently been shown to aid the adaptive T cell response in clearance of chronic viral infection. In contrast, the IL-7-related cytokine thymic stromal lymphopoietin (TSLP) has a limited role in lymphocyte development but is important in the immune response to parasitic worms and allergens. The role for these cytokines in the immune response to an acute viral infection is unclear. IL-7 and TSLP share IL-7Rα as part of their heterodimeric receptors with the gamma common chain (γc) and TSLPR, respectively. We investigated the role of IL-7 and TSLP in the primary immune response to influenza A infection using hypomorphic IL-7Rα (IL-7Rα^449F) and TSLPR^−/− mice. We found that IL-7, but not TSLP, plays an important role in control of influenza A virus. We also showed that IL-7 signaling was necessary for the generation of a robust influenza A-specific CD4 and CD8 T cell response and that this requirement is intrinsic to CD8 T cells. These findings demonstrate a significant role for IL-7 during acute viral infection.

Unusual timing of CD127 expression by mouse uterine natural killer cells

Decidualization, a progesterone-dependent process that alters endometrial stromal cells at implantation sites in humans and rodents, is accompanied by a highly regulated, NK cell-dominated leukocyte influx into decidual basalis (DB). Whether uNK cells differentiate from uterine progenitor cells is unknown, as are the mechanisms restricting leukocytes to DB. We asked if cells expressing the early NK lineage marker CD127 (IL-7Rα) occurred in mouse decidua. CD127 was absent from gd6.5 decidual lymphoid cells but became expressed by a mature uNK cell subset in gd10.5 DB. DB and transient myometrial structures (MLAp) that ring maternal blood vessels supplying placentae expressed IL-7 and TSLP, the CD127 ligands, but with differing temporal and spatial patterns. UNK cells expressed TSLPR, and study of gd10.5 implantation sites from mice deleted for IL-7, CD127, or TSLPR suggested that IL-7 and its receptor have physiological roles in limiting expansion of immature uNK cells within MLAp, while the TSLP signaling pathway is used in DB to sustain IFN-γ production from a subset of mature uNK cells. Regionalized, dynamic expression of the additional lymphoid organ stromal markers gp38/podoplanin and ER-TR7, but not CD157, were seen by immunohistochemistry in implantation sites, and DB and MLAp contained transcripts for Aire, a tolerance-promoting factor. These observations suggest that CD127(+) NK lineage progenitors are not present in the early postimplantation period of mouse uterus and that decidualized endometrial stroma has key immunoregulatory properties.

Impaired event memory and recollection in a case of developmental amnesia

A current debate in the literature is whether all declarative memories and associated memory processes rely on the same neural substrate. Here, we show that H.C., a developmental amnesic person with selective bilateral hippocampal volume loss, has a mild deficit in personal episodic memory, and a more pronounced deficit in public event memory; semantic memory for personal and general knowledge was unimpaired. This was accompanied by a subtle difference in impairment between recollection and familiarity on lab-based tests of recognition memory. Strikingly, H.C.'s recognition did not benefit from a levels-of-processing manipulation. Thus, not all types of declarative memory and related processes can exist independently of the hippocampus even if it is damaged early in life.

Elevated IL-7 availability does not account for T cell proliferation in moderate lymphopenia. (104.11)

Lymphopenia-induced proliferation (LIP) is a proliferative program initiated in response to T cell insufficiency caused by acute or chronic immunodepletion. Studies of lymphopenic mice have demonstrated that the cytokine IL-7 and TCR signaling are critical for LIP. We examined how these two factors impact T cell proliferation following transfer into moderately lymphopenic mice. We show here that moderate lymphopenia (~25% of WT lymphocytes) of IL-7Rα knock-in mutant (IL-7Rα449F) mice supports T cell proliferation, although with decreased frequency and kinetics compared to cells transferred to severely lymphopenic (5% of WT) IL-7Rα-/- hosts. Although previous studies have demonstrated that elevated IL-7 levels play an important role in LIP, IL-7 availability was not elevated in IL-7Rα449F mice. However, moderate lymphopenia increased access of transferred T cells to self-peptide presented on antigen presenting cells that can trigger TCR signaling and proliferation. Importantly, we did not detect significant changes in TCR Vβ usage of proliferated T cells recovered from either moderately or severely lymphopenic hosts. Our work demonstrates that polyclonal T cells retain a diverse TCR repertoire following proliferation mediated by either self-peptide/MHC interaction alone or in combination with IL-7, and that T cell reconstitution is most efficient in the presence of increased IL-7 availability.

Glucose stimulates human beta cell replication in vivo in islets transplanted into NOD-severe combined immunodeficiency (SCID) mice

AIMS/HYPOTHESIS

We determined whether hyperglycaemia stimulates human beta cell replication in vivo in an islet transplant model

METHODS

Human islets were transplanted into streptozotocin-induced diabetic NOD-severe combined immunodeficiency mice. Blood glucose was measured serially during a 2 week graft revascularisation period. Engrafted mice were then catheterised in the femoral artery and vein, and infused intravenously with BrdU for 4 days to label replicating beta cells. Mice with restored normoglycaemia were co-infused with either 0.9% (wt/vol.) saline or 50% (wt/vol.) glucose to generate glycaemic differences among grafts from the same donors. During infusions, blood glucose was measured daily. After infusion, human beta cell replication and apoptosis were measured in graft sections using immunofluorescence for insulin, and BrdU or TUNEL.

RESULTS

Human islet grafts corrected diabetes in the majority of cases. Among grafts from the same donor, human beta cell proliferation doubled in those exposed to higher glucose relative to lower glucose. Across the entire cohort of grafts, higher blood glucose was strongly correlated with increased beta cell replication. Beta cell replication rates were unrelated to circulating human insulin levels or donor age, but tended to correlate with donor BMI. Beta cell TUNEL reactivity was not measurably increased in grafts exposed to elevated blood glucose.

CONCLUSIONS/INTERPRETATION

Glucose is a mitogenic stimulus for transplanted human beta cells in vivo. Investigating the underlying pathways may point to mechanisms capable of expanding human beta cell mass in vivo.

CD45 regulates migration, proliferation, and progression of double negative 1 thymocytes

CD45 is a protein tyrosine phosphatase that is expressed on all nucleated hematopoietic cells, from stem cells to memory cells. Although its function in regulating the threshold of Ag receptor signaling is well established, its role in other leukocytes, particularly progenitor cells, is not well defined. In this study, we find CD45 affects early thymocyte development. Examination of the CD4(-)CD8(-) double negative (DN) populations revealed a significant reduction in the DN1 population, in both the numbers of CD117(+) DN1 cells (the early thymocyte progenitors) and the CD117(-) DN1 cells in the thymus of CD45(-/-) mice. There was also a reduced frequency of CCR9(+) Lin(-)Sca-1(+)c-Kit(+) cells and common lymphoid progenitors in the CD45(-/-) bone marrow. Competitive bone marrow reconstitution showed a reduced contribution of DN1 cells from CD45(-/-) cells, consistent with an intrinsic defect in these cells. CD45(-/-) DN1 cells exhibited reduced proliferation in vivo and reduced CXCL12-mediated migration in vitro. The loss of CD45 led to the accumulation of an intermediate DN1.5 thymocyte population in vivo that was dependent on Notch for progression. In vivo, CD117(-) DN1 cells gave rise to gammadelta T cells. In vitro, CD117(-) DN1 cells progressed to DN4 on OP9-DL1 cells but CD117(-) DN1 cells lacking CD45 did not. CD45(-/-) CD117(-) DN1 cells were also deficient in TCRbeta expression. Thus, CD45 deficiency affects the development and progression of DN1 thymocytes.