Immune checkpoints targeting dendritic cells for antibody-based modulation in cancer

Dendritic cells (DC) are professional antigen-presenting cells which link innate to adaptive immunity. DC play a central role in regulating antitumor T-cell responses in both tumor-draining lymph nodes (TDLN) and the tumor microenvironment (TME). They modulate effector T-cell responses via immune checkpoint proteins (ICPs) that can be either stimulatory or inhibitory. Functions of DC are often impaired by the suppressive TME leading to tumor immune escape. Therefore, better understanding of the mechanisms of action of ICPs expressed by (tumor-infiltrating) DC will lead to potential new treatment strategies. Genetic manipulation and high-dimensional analyses have provided insight in the interactions between DC and T-cells in TDLN and the TME upon ICP targeting. In this review, we discuss (tumor-infiltrating) DC lineage cells and tumor tissue specific "mature" DC states and their gene signatures in relation to anti-tumor immunity. We also review a number of ICPs expressed by DC regarding their functions in phagocytosis, DC activation, or inhibition and outline position in, or promise for clinical trials in cancer immunotherapy. Collectively, we highlight the critical role of DC and their exact status in the TME for the induction and propagation of T-cell immunity to cancer.

DeepAIR: A deep learning framework for effective integration of sequence and 3D structure to enable adaptive immune receptor analysis

Structural docking between the adaptive immune receptors (AIRs), including T cell receptors (TCRs) and B cell receptors (BCRs), and their cognate antigens are one of the most fundamental processes in adaptive immunity. However, current methods for predicting AIR-antigen binding largely rely on sequence-derived features of AIRs, omitting the structure features that are essential for binding affinity. In this study, we present a deep learning framework, termed DeepAIR, for the accurate prediction of AIR-antigen binding by integrating both sequence and structure features of AIRs. DeepAIR achieves a Pearson's correlation of 0.813 in predicting the binding affinity of TCR, and a median area under the receiver-operating characteristic curve (AUC) of 0.904 and 0.942 in predicting the binding reactivity of TCR and BCR, respectively. Meanwhile, using TCR and BCR repertoire, DeepAIR correctly identifies every patient with nasopharyngeal carcinoma and inflammatory bowel disease in test data. Thus, DeepAIR improves the AIR-antigen binding prediction that facilitates the study of adaptive immunity.

An update on studies characterizing adaptive immune responses in SARS-CoV-2 infection and COVID-19 vaccination

In this brief opinion piece, we highlight our studies characterizing adaptive SARS-CoV-2 immune responses in infection and vaccination, and the ability of SARS-CoV-2-specific T cells to recognize emerging variants of concern, and the role of pre-existing cross-reactive T cells. In the context of the debate on correlates of protection, the pandemic's progression in the past 3 years underlined the need to consider how different adaptive immune responses might differentially contribute to protection from SARS-CoV-2 infection versus COVID-19 disease. Lastly, we discuss how cross-reactive T cell responses may be useful in generating a broad adaptive immunity, recognizing different variants and viral families. Considering vaccines with broadly conserved antigens could improve preparedness for future infectious disease outbreaks.

Trans-generational immune priming is not mediated by the sex of the parent primed: a meta-analysis of invertebrate data

Traditionally, only vertebrates were thought capable of acquired immune responses, such as the ability to transfer immunological experience vertically to their offspring (known as trans-generational immune priming, TGIP). Increasing evidence challenges this belief and it is now clear that invertebrates also have the ability to exhibit functionally equivalent TGIP. This has led to a surge in papers exploring invertebrate TGIP, with most focusing on the costs, benefits or factors that affect the evolution of this trait. Whilst many studies have found support for the phenomenon, not all studies do, and there is considerable variation in the strength of positive results. To address this, we conducted a meta-analysis to answer the question: what is the overall effect of TGIP in invertebrates? Then, to understand the specific factors that affect its presence and intensity, we conducted a moderator analysis. Our results corroborate that TGIP occurs in invertebrates (demonstrated by a large, positive effect size). The strength of the positive effect was related to if and how offspring were immune challenged (i.e. whether they were challenged with the same or different insult as their parents or not challenged at all). Interestingly, there was no effect of the ecology or life history of the species or the sex of the parent or the offspring primed, and responses were comparable across different immune elicitors. Our publication bias testing suggests that the literature may suffer from some level of positive-result bias. However, even after accounting for potential bias, our effect size remains positive. Publication bias testing can be influenced by diversity in the data set, which was considerable in our data, even after moderator analysis. It is therefore conceivable that differences among studies could be caused by other moderators that were unable to be included in our meta-analysis. Nonetheless, our results suggest that TGIP does occur in invertebrates, whilst providing some potential avenues to examine the factors that account for variation in effect sizes.

Advancement and Applications of Nanotherapy for Cancer Immune Microenvironment

Cancer treatment has evolved rapidly due to major advances in tumor immunity research. However, due to the complexity, heterogeneity, and immunosuppressive microenvironment of tumors, the overall efficacy of immunotherapy is only 20%. In recent years, nanoparticles have attracted more attention in the field of cancer immunotherapy because of their remarkable advantages in biocompatibility, precise targeting, and controlled drug delivery. However, the clinical application of nanomedicine also faces many problems concerning biological safety, and the synergistic mechanism of nano-drugs with immunity remains to be elucidated. Our study summarizes the functional characteristics and regulatory mechanisms of nanoparticles in the cancer immune microenvironment and how nanoparticles activate and long-term stimulate innate immunity and adaptive immunity. Finally, the current problems and future development trends regarding the application of nanoparticles are fully discussed and prospected to promote the transformation and application of nanomedicine used in cancer treatment.

Human Dendritic Cell Enrichment and Their Activation of T Cells

Dendritic cells (DCs) enable the immune system to mount and modulate precisely targeted responses to various threats across the organism by bridging innate and adaptive immunity. Historically, DCs have been classified as conventional (cDC) and plasmacytoid (pDC). More recently, cDCs were acknowledged as a heterogenous population composed of several subsets. Examining the functional diversity of cDCs in healthy homeostasis and pathology requires a robust experimental pipeline, beginning with an efficient enrichment protocol in preparation for cell sorting. Unfortunately, several commercial DC enrichment kits were developed before the discovery of the more recently described DC populations. Here, we detail two approaches to enrich human blood DCs or certain DC subsets and an in vitro protocol to examine DC stimulation of naïve T cells. The methods employed here overcome many hurdles encountered while enriching human DC subsets. Basic Protocol 1 describes a method that will enrich pDC, Axl Siglec6-DC (AS-DC), cDC1, DC2, DC3, monocytes, and human HLA+ cells by crosslinking unwanted cells to erythrocytes. Basic Protocol 2 describes the enrichment of pDC, AS-DC, cDC1, and DC2 but not DC3 via a highly efficient negative magnetic selection that is valuable in circumstances where DC3 is not required. Finally, Basic Protocol 3 describes a conventional protocol to perform a Mixed leucocyte Reaction (MLR) following the isolation of these DC subsets. These methods detail the advantages and pitfalls when isolating a heterogeneous population of cells. © 2023 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Human peripheral mononuclear phagocyte enrichment Basic Protocol 2: DC enrichment of pDC, cDC1, AS-DC, and DC2 but not DC3 Basic Protocol 3: Basic mixed lymphocyte reaction protocol with sorted human DC subsets.

Repeated Lipoteichoic Acid Injection at Low Concentration Induces Capsular Contracture by Activating Adaptive Immune Response through the IL-6/STAT3 Signaling Pathway

BACKGROUND

Capsular contracture is the most common complication of breast implantation surgery. Bacterial contamination was considered to play an important role in the occurrence of capsular contracture, and Gram-positive bacteria such as Staphylococcus epidermidis were discovered in the clinical specimens. Lipoteichoic acid (LTA) was a component of the cell wall of Gram-positive bacteria and was sufficient in the pathogenicity of the bacteria. The authors assumed that LTA could trigger the immunologic response against the implant and cause capsular contracture.

METHODS

The authors developed a rat model of capsular contracture by repeated injection of 10 μg/mL LTA. The histologic changes of the capsule tissue were measured by hematoxylin and eosin, sirius red, Masson, and immunohistochemical staining. The expression of related cytokines was measured by quantitative real-time polymerase chain reaction. The downstream pathway activation was shown by Western blot. The authors also applied tocilizumab, an interleukin (IL)-6 receptor antagonist, to verify the role of IL-6 in this pathologic process.

RESULTS

The authors discovered that repeated LTA injection, at a low concentration, could induce the thickening of capsule tissue, the deposition of collagen fiber, and the activation of myofibroblasts. The IL-6/signal transducer and activator of transcription 3 signaling pathway was activated in this process, and the inhibition of IL-6 receptor could relieve the symptoms. B cells and T-helper cells, especially T-helper type 1, could be related to this phenomenon.

CONCLUSIONS

The authors' research corroborated that subclinical infection could trigger capsular contracture, and the immune system played an important role in this process. The authors' results provided a possible research direction for the mechanism of bacterial infection-induced immune response against breast implants.

CLINICAL RELEVANCE STATEMENT

The authors' research provides a possible research direction for the mechanism of bacterial infection-induced immune response against breast implants, and a potential target for predicting the prognosis of capsular contracture.

Functional tumor cell-intrinsic STING, not host STING, drives local and systemic antitumor immunity and therapy efficacy following cryoablation

BACKGROUND

Despite its potential utility in delivering direct tumor killing and in situ whole-cell tumor vaccination, tumor cryoablation produces highly variable and unpredictable clinical response, limiting its clinical utility. The mechanism(s) driving cryoablation-induced local antitumor immunity and the associated abscopal effect is not well understood.

METHODS

The aim of this study was to identify and explore a mechanism of action by which cryoablation enhances the therapeutic efficacy in metastatic tumor models. We used the subcutaneous mouse model of the rhabdomyosarcoma (RMS) cell lines RMS 76-9STINGwt or RMS 76-9STING-/-, along with other murine tumor models, in C57BL/6 or STING-/- (TMEM173-/- ) mice to evaluate local tumor changes, lung metastasis, abscopal effect on distant tumors, and immune cell dynamics in the tumor microenvironment (TME).

RESULTS

The results show that cryoablation efficacy is dependent on both adaptive immunity and the STING signaling pathway. Contrary to current literature dictating an essential role of host-derived STING activation as a driver of antitumor immunity in vivo, we show that local tumor control, lung metastasis, and the abscopal effect on distant tumor are all critically dependent on a functioning tumor cell-intrinsic STING signaling pathway, which induces inflammatory chemokine and cytokine responses in the cryoablated TME. This reliance extends beyond cryoablation to include intratumoral STING agonist therapy. Additionally, surveys of gene expression databases and tissue microarrays of clinical tumor samples revealed a wide spectrum of expressions among STING-related signaling components.

CONCLUSIONS

Tumor cell-intrinsic STING pathway is a critical component underlying the effectiveness of cryoablation and suggests that expression of STING-related signaling components may serve as a potential therapy response biomarker. Our data also highlight an urgent need to further characterize tumor cell-intrinsic STING pathways and the associated downstream inflammatory response evoked by cryoablation and other STING-dependent therapy approaches.

Intestinal Immune Imbalance is an Alarm in the Development of IBD

Immune regulation plays a crucial role in human health and disease. Inflammatory bowel disease (IBD) is a chronic relapse bowel disease with an increasing incidence worldwide. Clinical treatments for IBD are limited and inefficient. However, the pathogenesis of immune-mediated IBD remains unclear. This review describes the activation of innate and adaptive immune functions by intestinal immune cells to regulate intestinal immune balance and maintain intestinal mucosal integrity. Changes in susceptible genes, autophagy, energy metabolism, and other factors interact in a complex manner with the immune system, eventually leading to intestinal immune imbalance and the onset of IBD. These events indicate that intestinal immune imbalance is an alarm for IBD development, further opening new possibilities for the unprecedented development of immunotherapy for IBD.

Peripheral Blood and Nasopharyngeal Swab MiRNA-155 Expression in Infants with Respiratory Syncytial Virus Infection

INTRODUCTION

MicroRNA (miR) 155 has been implicated in the regulation of innate and adaptive immunity as well as antiviral responses, but its role during respiratory syncytial virus (RSV) infections is not known. The objective of this study was to investigate the expression of miR-155 using pharyngeal swabs and peripheral blood in infants with RSV infection and uninfected controls.

METHODS

A prospective age-matched study was conducted in primary care in Torino from 1 August 2018 to 31 January 2020. We enrolled 66 subjects, 29 of them patients with RSV infection and 37 age-matched uninfected controls, and collected pharyngeal swabs and peripheral blood in order to assess miR-155 expression with real-time stem-loop-TaqMan real-time PCR.

RESULTS

The data show that there is no correlation between pharyngeal swabs and peripheral blood with respect to miR-155 expression. The 1/ΔCq miR-155 expression levels in throat swabs in RSV bronchiolitis patients and healthy controls were 0.19 ± 0.11 and 0.21 ± 0.09, respectively, and were not significantly different between healthy controls and bronchiolitis (p = 0.8414). In the peripheral blood, miR-155 levels were higher than those of healthy control subjects: 0.1 ± 0.013 and 0.09 ± 0.0007, respectively; p = 0.0002.

DISCUSSION

Our data provide evidence that miR-155 expression is higher in peripheral blood during RSV infection but not in swabs. This difference in the timing of sample recruitment could explain the differences obtained in the results; miR-155 activation is probably only assessable in the very early stages of infection in the swab and remains visible for longer in the blood. New investigations are needed in order to clarify whether the miR-155 expression in swabs can be influenced by different stages of virus disease of infants.

Introduction to the special issue Amphibian immunity: stress, disease and ecoimmunology

Amphibian populations have been declining worldwide, with global climate changes and infectious diseases being among the primary causes of this scenario. Infectious diseases are among the primary drivers of amphibian declines, including ranavirosis and chytridiomycosis, which have gained more attention lately. While some amphibian populations are led to extinction, others are disease-resistant. Although the host's immune system plays a major role in disease resistance, little is known about the immune mechanisms underlying amphibian disease resistance and host-pathogen interactions. As ectotherms, amphibians are directly subjected to changes in temperature and rainfall, which modulate stress-related physiology, including immunity and pathogen physiology associated with diseases. In this sense, the contexts of stress, disease and ecoimmunology are essential for a better understanding of amphibian immunity. This issue brings details about the ontogeny of the amphibian immune system, including crucial aspects of innate and adaptive immunity and how ontogeny can influence amphibian disease resistance. In addition, the papers in the issue demonstrate an integrated view of the amphibian immune system associated with the influence of stress on immune-endocrine interactions. The collective body of research presented herein can provide valuable insights into the mechanisms underlying disease outcomes in natural populations, particularly in the context of changing environmental conditions. These findings may ultimately enhance our ability to forecast effective conservation strategies for amphibian populations. This article is part of the theme issue 'Amphibian immunity: stress, disease and ecoimmunology'.

Innate and Adaptive Immunity-Related Markers as Predictors of the Short-Term Progression of Subclinical Atherosclerosis in Middle-Aged Patients

Assessment of inflammation is a promising approach to monitoring the progression of asymptomatic atherosclerosis. The aim of the present study was to investigate the predictive value of innate and adaptive immunity-related markers, in relation to the short-term progression of subclinical atherosclerosis. The study included 183 patients aged 40-64 years who underwent duplex scanning of the carotid and lower limb arteries at two visits with an interval of 12-24 months between examinations. Phenotyping of circulating lymphocytes and monocytes subpopulations were performed through flow cytometry. An increase in the number of circulating TLR4-positive intermediate monocytes (>447.0-467.0 cells/μL) was an independent predictor of the short-term progression of lower limb artery atherosclerosis (p < 0.0001) and polyvascular atherosclerosis (p = 0.003). The assessment of TLR4-positive monocytes significantly improved the prognostic model for the progression of lower limb arterial atherosclerosis (C-index 0.728 (0.642-0.815) versus 0.637 (0.539-0.735); p = 0.038). An increase in the number of circulating TLR4-positive intermediate monocytes was an independent predictor of the short-term progression of lower limb artery and polyvascular atherosclerosis. Their inclusion into models containing conventional risk factors significantly improved their prognostic effectiveness regarding lower limb artery atherosclerosis progression.

The podocyte: glomerular sentinel at the crossroads of innate and adaptive immunity

Focal segmental glomerulosclerosis (FSGS) is a common glomerular disorder that manifests clinically with the nephrotic syndrome and has a propensity to recur following kidney transplantation. The pathophysiology and therapies available to treat FSGS currently remain elusive. Since the podocyte appears to be the target of apparent circulating factor(s) that lead to recurrence of proteinuria following kidney transplantation, this article is focused on the podocyte. In the context of kidney transplantation, the performance of pre- and post-reperfusion biopsies, and the establishment of in vitro podocyte liquid biopsies/assays allow for the development of clinically relevant studies of podocyte biology. This has given insight into new pathways, involving novel targets in innate and adaptive immunity, such as SMPDL3b, cGAS-STING, and B7-1. Elegant experimental studies suggest that the successful clinical use of rituximab and abatacept, two immunomodulating agents, in our case series, may be due to direct effects on the podocyte, in addition to, or perhaps distinct from their immunosuppressive functions. Thus, tissue biomarker-directed therapy may provide a rational approach to validate the mechanism of disease and allow for the development of new therapeutics for FSGS. This report highlights recent progress in the field and emphasizes the importance of kidney transplantation and recurrent FSGS (rFSGS) as a platform for the study of primary FSGS.

Dietary restriction to optimize T cell immunity is an ancient survival strategy conserved in vertebrate evolution

Recent advances highlight a key role of transient fasting in optimizing immunity of human and mouse. However, it remains unknown whether this strategy is independently acquired by mammals during evolution or instead represents gradually evolved functions common to vertebrates. Using a tilapia model, we report that T cells are the main executors of the response of the immune system to fasting and that dietary restriction bidirectionally modulates T cell immunity. Long-term fasting impaired T cell immunity by inducing intense autophagy, apoptosis, and aberrant inflammation. However, transient dietary restriction triggered moderate autophagy to optimize T cell response by maintaining homeostasis, alleviating inflammation and tissue damage, as well as enhancing T cell activation, proliferation and function. Furthermore, AMPK is the central hub linking fasting and autophagy-controlled T cell immunity in tilapia. Our findings demonstrate that dietary restriction to optimize immunity is an ancient strategy conserved in vertebrate evolution, providing novel perspectives for understanding the adaptive evolution of T cell response.

Single-dose injectable nanovaccine-in-hydrogel for robust immunotherapy of large tumors with abscopal effect

Current cancer immunotherapy [e.g., immune checkpoint blockade (ICB)] only benefits small subsets of patients, largely due to immunosuppressive tumor microenvironment (TME). In situ tumor vaccination can reduce TME immunosuppression and thereby improve cancer immunotherapy. Here, we present single-dose injectable (nanovaccines + ICBs)-in-hydrogel (NvIH) for robust immunotherapy of large tumors with abscopal effect. NvIH is thermo-responsive hydrogel co-encapsulated with ICB antibodies and novel polymeric nanoparticles loaded with three immunostimulatory agonists for Toll-like receptors 7/8/9 (TLR7/8/9) and stimulator of interferon genes (STING). Upon in situ tumor vaccination, NvIH undergoes rapid sol-to-gel transformation, prolongs tumor retention, sustains the release of immunotherapeutics, and reduces acute systemic inflammation. In multiple poorly immunogenic tumor models, single-dose NvIH reduces multitier TME immunosuppression, elicits potent TME and systemic innate and adaptive antitumor immunity with memory, and regresses both local (vaccinated) and distant large tumors with abscopal effect, including distant orthotopic glioblastoma. Overall, NvIH holds great potential for tumor immunotherapy.

Immunomodulatory actions of vitamin D in various immune-related disorders: a comprehensive review

For many years, vitamin D has been acknowledged for its role in maintaining calcium and phosphate balance. However, in recent years, research has assessed its immunomodulatory role and come up with conflicting conclusions. Because the vitamin D receptor is expressed in a variety of immune cell types, study into the precise role of this molecule in diseases, notably autoimmune disorders, has been made possible. The physiologically activated version of vitamin D also promotes a tolerogenic immunological condition in addition to modulating innate and acquired immune cell responses. According to a number of recent studies, this important micronutrient plays a complex role in numerous biochemical pathways in the immune system and disorders that are associated with them. Research in this field is still relatively new, and some studies claim that patients with severe autoimmune illnesses frequently have vitamin D deficiencies or insufficiencies. This review seeks to clarify the most recent research on vitamin D's immune system-related roles, including the pathophysiology of major disorders.

Immunogenomic profile at baseline predicts host susceptibility to clinical malaria

Introduction

Host gene and protein expression impact susceptibility to clinical malaria, but the balance of immune cell populations, cytokines and genes that contributes to protection, remains incompletely understood. Little is known about the determinants of host susceptibility to clinical malaria at a time when acquired immunity is developing.

Methods

We analyzed peripheral blood mononuclear cells (PBMCs) collected from children who differed in susceptibility to clinical malaria, all from a small town in Mali. PBMCs were collected from children aged 4-6 years at the start, peak and end of the malaria season. We characterized the immune cell composition and cytokine secretion for a subset of 20 children per timepoint (10 children with no symptomatic malaria age-matched to 10 children with >2 symptomatic malarial illnesses), and gene expression patterns for six children (three per cohort) per timepoint.

Results

We observed differences between the two groups of children in the expression of genes related to cell death and inflammation; in particular, inflammatory genes such as CXCL10 and STAT1 and apoptotic genes such as XAF1 were upregulated in susceptible children before the transmission season began. We also noted higher frequency of HLA-DR+ CD4 T cells in protected children during the peak of the malaria season and comparable levels cytokine secretion after stimulation with malaria schizonts across all three time points.

Conclusion

This study highlights the importance of baseline immune signatures in determining disease outcome. Our data suggests that differences in apoptotic and inflammatory gene expression patterns can serve as predictive markers of susceptibility to clinical malaria.

Plasmacytoid dendritic cells: A dendritic cell in disguise

Since their discovery, the identity of plasmacytoid dendritic cells (pDCs) has been at the center of a continuous dispute in the field, and their classification as dendritic cells (DCs) has been recently re-challenged. pDCs are different enough from the rest of the DC family members to be considered a lineage of cells on their own. Unlike the exclusive myeloid ontogeny of cDCs, pDCs may have dual origin developing from myeloid and lymphoid progenitors. Moreover, pDCs have the unique ability to quickly secrete abundant levels of type I interferon (IFN-I) in response to viral infections. In addition, pDCs undergo a differentiation process after pathogen recognition that allows them to activate T cells, a feature that has been shown to be independent of presumed contaminating cells. Here, we aim to provide an overview of the historic and current understanding of pDCs and argue that their classification as either lymphoid or myeloid may be an oversimplification. Instead, we propose that the capacity of pDCs to link the innate and adaptive immune response by directly sensing pathogens and activating adaptive immune responses justify their inclusion within the DC network.

A role for immune modulation in achieving functional cure for chronic hepatitis B among current changes in the landscape of new treatments

INTRODUCTION

Chronic hepatitis B (CHB) is rarely cured using available treatments. Barriers to cure are: 1) persistence of reservoirs of hepatitis B virus (HBV) replication and antigen production (HBV DNA); 2) high burden of viral antigens that promote T cell exhaustion with T cell dysfunction; 3) CHB-induced impairment of immune responses.

AREAS COVERED

We discuss options for new therapies that could address one or more of the barriers to functional cure, with particular emphasis on the potential role of immunotherapy.

EXPERT OPINION/COMMENTARY

Ideally, a sterilizing cure for CHB would translate into finite therapies that result in loss of HBV surface antigen and eradication of HBV DNA. Restoration of a functional adaptive immune response, a key facet of successful CHB treatment, remains elusive. Numerous strategies targeting the high viral DNA and antigen burden and aiming to restore the host immune responses will enter clinical development in coming years. Most patients are likely to require combinations of several drugs, personalized according to virologic and disease characteristics, patient preference, accessibility, and affordability. The management of CHB is a global health priority. Expedited drug development requires collaborations between regulatory agencies, scientists, clinicians, and within the industry to facilitate testing of the best drug combinations.

Glomerulonephritis: immunopathogenesis and immunotherapy

'Glomerulonephritis' (GN) is a term used to describe a group of heterogeneous immune-mediated disorders characterized by inflammation of the filtration units of the kidney (the glomeruli). These disorders are currently classified largely on the basis of histopathological lesion patterns, but these patterns do not align well with their diverse pathological mechanisms and hence do not inform optimal therapy. Instead, we propose grouping GN disorders into five categories according to their immunopathogenesis: infection-related GN, autoimmune GN, alloimmune GN, autoinflammatory GN and monoclonal gammopathy-related GN. This categorization can inform the appropriate treatment; for example, infection control for infection-related GN, suppression of adaptive immunity for autoimmune GN and alloimmune GN, inhibition of single cytokines or complement factors for autoinflammatory GN arising from inborn errors in innate immunity, and plasma cell clone-directed or B cell clone-directed therapy for monoclonal gammopathies. Here we present the immunopathogenesis of GN and immunotherapies in use and in development and discuss how an immunopathogenesis-based GN classification can focus research, and improve patient management and teaching.

Hybrid immunity against reinfection with SARS-CoV-2 following a previous SARS-CoV-2 infection and single dose of the BNT162b2 vaccine in children and adolescents: a target trial emulation

BACKGROUND

Although most children and adolescents have had a previous SARS-CoV-2 infection and many continue to receive COVID-19 vaccinations, studies of the effectiveness of hybrid immunity against reinfection with the omicron (B.1.1.529) variant are scarce. We aimed to examine the effectiveness of vaccination in convalescent children and adolescents against reinfection with the delta (B.1.617.2) variant and the BA.1 and BA.2 and BA.4 and BA.5 omicron subvariants.

METHODS

This retrospective cohort study was devised to emulate a target randomised control trial using a retrospective dataset of anonymised health records of children (5-11 years old) and adolescents (12-16 years old) who were members of the Maccabi Healthcare Services, Israel. The design emulated 91 randomised trials by devising a series of multiple nested trials, compiling the results into a single dataset, and fitting Cox proportional hazards models to estimate adjusted hazard ratios (HRs) with 95% CIs of each measured outcome. The primary aim was to assess the protection from reinfection with the delta variant and the BA.1 and BA.2 and BA.4 and BA.5 omicron subvariants associated with hybrid immunity as a result of a previous SARS-CoV-2 infection followed by vaccination with the BNT162b2 (Pfizer-BioNTech) vaccine.

FINDINGS

Data from between from March 1, 2020, to July 31, 2022, for 163 812 individuals (120 721 children [59 404 girls and 61 317 boys], median age 8·0 years [IQR 6·7 to 10·2]; and 43 091 adolescents [21 239 girls and 21 852 boys], median age 13·5 years [12·6 to 14·8]) were included in at least one trial. A single dose of the BNT162b2 vaccine in convalescent children and adolescents confers statistically significant protection against the delta variant (78% [95% CI 72 to 83] in adolescents and 64% [3 to 87] in children) and the omicron BA.1 and BA.2 subvariants (54% [50 to 57] in adolescents and 71% [67 to 73] in children) compared with children who had a previous infection but were unvaccinated. However, the vaccine was not found to confer statistically significant protection against the BA.4 and BA.5 omicron subvariants in adolescents (8% [-18 to 29]) and children (12% [-6 to 27]).

INTERPRETATION

Decision makers in BA.4 and BA.5 dominant regions should re-examine whether convalescent individuals aged 5-16 years should receive the BNT162b2 vaccine to prevent future reinfection, especially in light of reports that show that most children and adolescents have already been infected with SARS-CoV-2.

FUNDING

None.

Gene-encoded nanoparticle vaccine platforms for in vivo assembly of multimeric antigen to promote adaptive immunity

Nanoparticle vaccines are a diverse category of vaccines for the prophylaxis or treatment of various diseases. Several strategies have been employed for their optimization, especially to enhance vaccine immunogenicity and generate potent B-cell responses. Two major modalities utilized for particulate antigen vaccines include using nanoscale structures for antigen delivery and nanoparticles that are themselves vaccines due to antigen display or scaffolding-the latter of which we will define as "nanovaccines." Multimeric antigen display has a variety of immunological benefits compared to monomeric vaccines mediated through potentiating antigen-presenting cell presentation and enhancing antigen-specific B-cell responses through B-cell activation. The majority of nanovaccine assembly is done in vitro using cell lines. However, in vivo assembly of scaffolded vaccines potentiated using nucleic acids or viral vectors is a burgeoning modality of nanovaccine delivery. Several advantages to in vivo assembly exist, including lower costs of production, fewer production barriers, as well as more rapid development of novel vaccine candidates for emerging diseases such as SARS-CoV-2. This review will characterize the methods for de novo assembly of nanovaccines in the host using methods of gene delivery including nucleic acid and viral vectored vaccines. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Biology-Inspired Nanomaterials > Nucleic Acid-Based Structures Biology-Inspired Nanomaterials > Protein and Virus-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.

are prevalent in wild mice and protect from lethal Citrobacter rodentium infection in the absence of adaptive immunity

Transfer of the gut microbiota from wild to laboratory mice alters the host's immune status and enhances resistance to infectious and metabolic diseases, but understanding of which microbes and how they promote host fitness is only emerging. Our analysis of metagenomic sequencing data reveals that Helicobacter spp. are enriched in wild compared with specific-pathogen-free (SPF) and conventionally housed mice, with multiple species commonly co-colonizing their hosts. We create laboratory mice harboring three non-SPF Helicobacter spp. to evaluate their effect on mucosal immunity and colonization resistance to the enteropathogen Citrobacter rodentium. Our experiments reveal that Helicobacter spp. interfere with C. rodentium colonization and attenuate C. rodentium-induced gut inflammation in wild-type (WT) mice, even preventing lethal infection in Rag2-/- SPF mice. Further analyses suggest that Helicobacter spp. interfere with tissue attachment of C. rodentium, putatively by reducing the availability of mucus-derived sugars. These results unveil pivotal protective functions of wild mouse microbiota constituents against intestinal infection.

Intravenous heterologous prime-boost vaccination activates innate and adaptive immunity to promote tumor regression

Therapeutic neoantigen cancer vaccines have limited clinical efficacy to date. Here, we identify a heterologous prime-boost vaccination strategy using a self-assembling peptide nanoparticle TLR-7/8 agonist (SNP) vaccine prime and a chimp adenovirus (ChAdOx1) vaccine boost that elicits potent CD8 T cells and tumor regression. ChAdOx1 administered intravenously (i.v.) had 4-fold higher antigen-specific CD8 T cell responses than mice boosted by the intramuscular (i.m.) route. In the therapeutic MC38 tumor model, i.v. heterologous prime-boost vaccination enhances regression compared with ChAdOx1 alone. Remarkably, i.v. boosting with a ChAdOx1 vector encoding an irrelevant antigen also mediates tumor regression, which is dependent on type I IFN signaling. Single-cell RNA sequencing of the tumor myeloid compartment shows that i.v. ChAdOx1 reduces the frequency of immunosuppressive Chil3 monocytes and activates cross-presenting type 1 conventional dendritic cells (cDC1s). The dual effect of i.v. ChAdOx1 vaccination enhancing CD8 T cells and modulating the TME represents a translatable paradigm for enhancing anti-tumor immunity in humans.

N-Arylpyrazole NOD2 Agonists Promote Immune Checkpoint Inhibitor Therapy

The characterization of microbiota mechanisms in health and disease has reinvigorated pattern recognition receptors as prominent targets for immunotherapy. Notably, our recent studies on Enterococcus species revealed peptidoglycan remodeling and activation of NOD2 as key mechanisms for microbiota enhancement of immune checkpoint inhibitor therapy. Inspired by this work and other studies of NOD2 activation, we performed in silico ligand screening and developed N-arylpyrazole dipeptides as novel NOD2 agonists. Importantly, our N-arylpyrazole NOD2 agonist is enantiomer-specific and effective at promoting immune checkpoint inhibitor therapy and requires NOD2 for activity in vivo. Given the significant functions of NOD2 in innate and adaptive immunity, these next-generation agonists afford new therapeutic leads and adjuvants for a variety of NOD2-responsive diseases.

Rejection of Lepeophtheirus salmonis driven in part by chitin sensing is not impacted by seawater acclimitization in Coho salmon (Oncorhynchus kisutch)

There is tremendous variation in life-history strategies among anadromous salmonids. Species that enter the ocean environment at small sizes (< 20 g) are likely under more physiological pressure from pathogens; however, little data is available on responses at these early stages. With this in mind, we performed salmon louse challenges with Coho salmon either immediately after seawater entry (SW; ca. 10 g) or after 30 days in SW (ca. 20 g). Irrespective of size or time in SW, parasites were rapidly rejected by the host, with > 90% of all parasites lost by 16 days post-infection (dpi). Rejection was concomitant with host epithelial granulomatous infiltrations that initially targeted the embedded frontal filament (4 dpi) and the entire parasite by 10 dpi. Illumina sequencing, followed by functional enrichment analysis, revealed a concerted defense response in the fin within 1 dpi that included multiple innate and adaptive immunity components. Strikingly, early indications of an allergic-type inflammatory response were associated with chitin sensing pathways orchestrated by early overexpression of the IgE-receptor, fcer1g. Additionally, there was profound overexpression of several classes of c-type lectin receptors, including dectin-2, mincle, and dc-sign at 1 dpi onward. These profiles and upregulation of cellular effector markers were corroborated by histopathological evaluation, revealing the simultaneous presence of mast cell/eosinophilic granular cells, sacciform cells, macrophages/histiocytes, and granulocytes in fin. At 10 dpi and concurrent with parasite expulsion, there was evidence of immunoregulation in addition to tissue remodelling pathways. At 16 dpi, the response was effectively abrogated. Simultaneous profiling of the parasite transcriptome revealed early induction of chitin metabolism and immunomodulation, toxin production and ECM degradation; however, after 7 dpi, these were replaced with overexpression of stress and immune defense genes. These data present the first evidence for Coho salmon demonstrating chitin- and sugar moiety-sensing as key drivers of salmon louse rejection.

The immune role of the intestinal microbiome in knee osteoarthritis: a review of the possible mechanisms and therapies

Osteoarthritis (OA) is a chronic degenerative joint disease characterized by cartilage damage and synovial inflammation and carries an enormous public health and economic burden. It is crucial to uncover the potential mechanisms of OA pathogenesis to develop new targets for OA treatment. In recent years, the pathogenic role of the gut microbiota in OA has been well recognized. Gut microbiota dysbiosis can break host-gut microbe equilibrium, trigger host immune responses and activate the "gut-joint axis", which aggravates OA. However, although the role of the gut microbiota in OA is well known, the mechanisms modulating the interactions between the gut microbiota and host immunity remain unclear. This review summarizes research on the gut microbiota and the involved immune cells in OA and interprets the potential mechanisms for the interactions between the gut microbiota and host immune responses from four aspects: gut barrier, innate immunity, adaptive immunity and gut microbiota modulation. Future research should focus on the specific pathogen or the specific changes in the gut microbiota composition to identify the related signaling pathways involved in the pathogenesis of OA. In addition, future studies should include more novel interventions on immune cell modifications and gene regulation of specific gut microbiota related to OA to validate the application of gut microbiota modulation in the onset of OA.

Nuanced role for dendritic cell intrinsic IRE1 RNase in the regulation of antitumor adaptive immunity

In cancer, activation of the IRE1/XBP1s axis of the unfolded protein response (UPR) promotes immunosuppression and tumor growth, by acting in cancer cells and tumor infiltrating immune cells. However, the role of IRE1/XBP1s in dendritic cells (DCs) in tumors, particularly in conventional type 1 DCs (cDC1s) which are cellular targets in immunotherapy, has not been fully elucidated. Here, we studied the role of IRE1/XBP1s in subcutaneous B16/B78 melanoma and MC38 tumors by generating loss-of-function models of IRE1 and/or XBP1s in DCs or in cDC1s. Data show that concomitant deletion of the RNase domain of IRE1 and XBP1s in DCs and cDC1s does not influence the kinetics of B16/B78 and MC38 tumor growth or the effector profile of tumor infiltrating T cells. A modest effect is observed in mice bearing single deletion of XBP1s in DCs, which showed slight acceleration of melanoma tumor growth and dysfunctional T cell responses, however, this effect was not recapitulated in animals lacking XBP1 only in cDC1s. Thus, evidence presented here argues against a general pro-tumorigenic role of the IRE1/XBP1s pathway in tumor associated DC subsets.

Adaptive Immunity in Genitourinary Cancers

CONTEXT

While urothelial and renal cell cancers have exhibited modest responses to novel immune checkpoint inhibitors targeting the programmed death ligand 1 and its receptor, response rates in patients with prostate cancer have remained poor. The factors underlying suboptimal outcomes observed in patients treated with novel immunotherapies are still to be resolved.

OBJECTIVE

To review the literature and describe the key adaptive immune physiological events associated with cancer progression and therapeutic response in genitourinary (GU) cancers.

EVIDENCE ACQUISITION

We performed a nonsystematic, collaborative narrative review to highlight recent advancements leading to the current state of knowledge on the critical mediators of antitumor adaptive immunity to GU cancers. Further, we discuss the findings on the pre- and post-treatment immunological events that either are unique to each of the three cancer types or exhibit overlapping clinical associations.

EVIDENCE SYNTHESIS

Aging-associated immune function decline is a major factor underlying poor outcomes observed in patients treated with both conventional and novel immunotherapies. Other cancer immunobiological aspects associated with suboptimal responses in GU cancers include the overall tumor mutational burden, mutations in specific tumor suppressor/DNA damage repair genes (KDM6A, PTEN, STAG2, TP53, ATM, and BRCA2), and abundance of multiple functional states of adaptive immune cells and their spatiotemporal localization within the tumor immune microenvironment. Understanding these mechanisms may potentially lead to the development of prognostic and predictive biomarkers such as immune cell infiltration profiles and tertiary lymphoid structures (TLSs) that associate with variable clinical outcomes depending on the nature of the novel immunotherapeutic approach. Implementation of newer immune-monitoring technologies and improved preclinical modeling systems will augment our understanding of the host and tumor intrinsic factors contributing to the variability of responses to immunotherapies.

CONCLUSIONS

Despite the tremendous progress made in the understanding of dynamic and static adaptive immune elements within the tumor immune landscape, several knowledge gaps remain. A comprehensive knowledge thus gained will lead to precision immunotherapy, improved drug sequencing, and a therapeutic response.

PATIENT SUMMARY

We performed a collaborative review by a diverse group of experts in the field to examine our understanding of the events and crosstalk between cancer cells and the patient's immune system that are associated with responses to novel immunotherapies. An evolving understanding of tumor-intrinsic and host-related immune alterations, both before and after therapy, will aid in the discovery of promising markers of responses to immunotherapy as well as the development of unique therapeutic approaches for the management of genitourinary cancers.

Dynamics of Naturally Acquired Immunity Against Severe Acute Respiratory Syndrome Coronavirus 2 in Children and Adolescents

OBJECTIVE

To evaluate the duration of protection against reinfection conferred by a previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in children and adolescents.

STUDY DESIGN

We applied 2 complementary approaches: a matched test-negative, case-control design and a retrospective cohort design. A total of 458 959 unvaccinated individuals aged 5-18 years were included. The analyses focused on the period July 1, 2021, to December 13, 2021, a period of Delta variant dominance in Israel. We evaluated 3 SARS-CoV-2-related outcomes: documented polymerase chain reaction-confirmed infection or reinfection, symptomatic infection or reinfection, and SARS-CoV-2-related hospitalization or death.

RESULTS

Overall, children and adolescents who were previously infected acquired durable protection against reinfection with SARS-CoV-2 for at least 18 months. Importantly, no SARS-CoV-2-related deaths were recorded in either the SARS-CoV-2-naïve group or the previously infected group. The effectiveness of naturally acquired immunity against a recurrent infection reached 89.2% (95% CI, 84.7%-92.4%) at 3-6 months after the first infection and declined slightly to 82.5% (95% CI, 79.1%-85.3%) by 9-12 months after infection, with a slight nonsignificant waning trend seen up to 18 months after infection. Additionally, children aged 5-11 years exhibited no significant waning of naturally acquired protection throughout the outcome period, whereas waning protection in those aged 12-18 years was more prominent but still mild.

CONCLUSIONS

Children and adolescents who were previously infected with SARS-CoV-2 remain protected to a high degree for 18 months. Further research is needed to examine naturally acquired immunity against Omicron and newer emerging variants.

Targeted Therapy for the Predominant Form of Mastocytosis

Mast cells are present in all vascularized tissues, often associated with blood vessels, glandular structures, and nerves, and they tend to be more numerous in tissues that interface with the external environment, including the skin and gastrointestinal tract. These mast cells are involved in both innate and acquired immunity, as well as in other biologic processes, including wound healing. Mast cell numbers within tissues are remarkably consistent, although mast cell numbers somewhat increase in association with inflammation. Human mast cells have two principal receptors that when stimulated, lead to cellular activation.

Endemic, epidemic and pandemic infections: the roles of natural and acquired herd immunity

PURPOSE OF REVIEW

This review summarizes the general concepts of innate and acquired immunity, including vaccine use and hesitancy, as they relate to reduction of the global burden of highly communicable infectious diseases.

RECENT FINDINGS

Vaccination to increase herd immunity remains the cornerstone of disease prevention worldwide yet global vaccination goals are not being met. Modern obstacles to vaccine acceptance include hesitancy, reduced altruistic intentions, impact of COVID-19, distrust of science and governmental agencies as well as recent geopolitical and environmental disasters. Together, such barriers have negatively impacted immunization rates worldwide, resulting in epidemics and pandemics of serious life-threatening infections from vaccine-preventable diseases, especially those affecting children. In addition, pathogens thought to be controlled or eradicated are reemerging with new genetic traits, making them more able to evade natural and acquired immunity, including that induced by available vaccines. Lastly, many serious and widespread infectious diseases await development and utilization of efficacious vaccines.

SUMMARY

The global burden of communicable diseases remains high, necessitating continued pathogen surveillance as well as vaccine development, deployment and continued efficacy testing. Equally important is the need to educate aggressively the people and their leaders on the benefits of vaccination to the individual, local community and the human population as a whole.

The Emerging Roles of the Adaptive Immune Response in Acute Pancreatitis

Acute pancreatitis (AP) is an abrupt, variable inflammatory condition of the pancreas, potentially escalating to severe systemic inflammation, rampant pancreatic necrosis, and multi-organ failure. Its complex pathogenesis involves an intricate immune response, with different T cell subsets (Th1, Th2, Th9, Th17, Th22, TFH, Treg, and CD8+ T cells) and B cells playing pivotal roles. Early T cell activation initiates the AP development, triggering cytokines associated with the Th1 response, which stimulate macrophages and neutrophils. Other T cell phenotypes contribute to AP's pathogenesis, and the balance between pro-inflammatory and anti-inflammatory cytokines influences its progression. Regulatory T and B cells are crucial for moderating the inflammatory response and promoting immune tolerance. B cells further contribute through antibody production, antigen presentation, and cytokine secretion. Understanding these immune cells' roles in AP could aid in developing new immunotherapies to enhance patient outcomes. However, further research is required to define these cells' precise roles in AP and their potential as therapeutic targets.

A tissue injury sensing and repair pathway distinct from host pathogen defense

Pathogen infection and tissue injury are universal insults that disrupt homeostasis. Innate immunity senses microbial infections and induces cytokines/chemokines to activate resistance mechanisms. Here, we show that, in contrast to most pathogen-induced cytokines, interleukin-24 (IL-24) is predominately induced by barrier epithelial progenitors after tissue injury and is independent of microbiome or adaptive immunity. Moreover, Il24 ablation in mice impedes not only epidermal proliferation and re-epithelialization but also capillary and fibroblast regeneration within the dermal wound bed. Conversely, ectopic IL-24 induction in the homeostatic epidermis triggers global epithelial-mesenchymal tissue repair responses. Mechanistically, Il24 expression depends upon both epithelial IL24-receptor/STAT3 signaling and hypoxia-stabilized HIF1α, which converge following injury to trigger autocrine and paracrine signaling involving IL-24-mediated receptor signaling and metabolic regulation. Thus, parallel to innate immune sensing of pathogens to resolve infections, epithelial stem cells sense injury signals to orchestrate IL-24-mediated tissue repair.

Nanoplastics Shape Adaptive Anticancer Immunity in the Colon in Mice

The impact of nanoplastics (NPs) on human health is still not well understood, and more research is needed to better understand the risks associated with these particles. In this study, we found that oral administration of polyethylene (PE) NPs in a mice model significantly disrupted the intestinal microenvironment, which shapes adaptive immune response and favors the established in situ colorectal tumor growth. Using single-cell RNA sequencing technology, we show that NPs triggered colon IL-1β-producing macrophages by inducing lysosome damage, leading to colonic Treg and Th17 differentiation associated with T cell exhaustion, which creates a colon environment that favors the tumor initiation and progress. A similar effect is also observed in polystyrene NPs. Our result provides insight into the potential link between NPs ingestion and colon tumorigenesis, and the urgency of addressing plastic pollution worldwide.

COVID-19 convalescent plasma boosts early antibody titer and does not influence the adaptive immune response

Multiple randomized, controlled clinical trials have yielded discordant results regarding the efficacy of convalescent plasma in outpatients, with some showing an approximately 2-fold reduction in risk and others showing no effect. We quantified binding and neutralizing antibody levels in 492 of the 511 participants from the Clinical Trial of COVID-19 Convalescent Plasma in Outpatients (C3PO) of a single unit of COVID-19 convalescent plasma (CCP) versus saline infusion. In a subset of 70 participants, peripheral blood mononuclear cells were obtained to define the evolution of B and T cell responses through day 30. Binding and neutralizing antibody responses were approximately 2-fold higher 1 hour after infusion in recipients of CCP compared with saline plus multivitamin, but levels achieved by the native immune system by day 15 were almost 10-fold higher than those seen immediately after CCP administration. Infusion of CCP did not block generation of the host antibody response or skew B or T cell phenotype or maturation. Activated CD4+ and CD8+ T cells were associated with more severe disease outcome. These data show that CCP leads to a measurable boost in anti-SARS-CoV-2 antibodies but that the boost is modest and may not be sufficient to alter disease course.

Depletion of Ly6G-Expressing Neutrophilic Cells Leads to Altered Peripheral T-Cell Homeostasis and Thymic Development in Neonatal Mice

Newborns and especially preterm infants are much more susceptible to infections than adults. Due to immature adaptive immunity, especially innate immune cells play an important role in a newborn's infection defense. Neonatal neutrophils exhibit profound differences in their functionality compared to neutrophils of adults. In particular, neonates possess a relevant population of suppressive neutrophils, which not only inhibit but also specifically modulate the function of T-cells. In this study, we investigated whether neonatal neutrophils are already involved in T-cell development in the thymus. For this purpose, we used a newly developed model of antibody-mediated immune cell depletion in which we administered a depleting antibody to pregnant and then lactating dams. Using this method, we were able to sufficiently deplete Ly6G-positive neutrophils in offspring. We demonstrated that the depletion of neutrophils in newborn mice resulted in altered peripheral T-cell homeostasis with a decreased CD4+/CD8+ T-cell ratio and decreased expression of CD62L. Neutrophil depletion even affected T-cell development in the thymus, with increased double positive thymocytes and a decreased CD4+/CD8+ single positive thymocyte ratio. Altogether, we demonstrated a previously unknown mechanism mediating neutrophils' immunomodulatory effects in newborns.

Die Kämpfe únd schláchten-the struggles and battles of innate-like effector T lymphocytes with microbes

The large majority of lymphocytes belong to the adaptive immune system, which are made up of B2 B cells and the αβ T cells; these are the effectors in an adaptive immune response. A multitudinous group of lymphoid lineage cells does not fit the conventional lymphocyte paradigm; it is the unconventional lymphocytes. Unconventional lymphocytes-here called innate/innate-like lymphocytes, include those that express rearranged antigen receptor genes and those that do not. Even though the innate/innate-like lymphocytes express rearranged, adaptive antigen-specific receptors, they behave like innate immune cells, which allows them to integrate sensory signals from the innate immune system and relay that umwelt to downstream innate and adaptive effector responses. Here, we review natural killer T cells and mucosal-associated invariant T cells-two prototypic innate-like T lymphocytes, which sense their local environment and relay that umwelt to downstream innate and adaptive effector cells to actuate an appropriate host response that confers immunity to infectious agents.

Modeling the SARS-CoV-2 Omicron variant dynamics in the United States with booster dose vaccination and waning immunity

We carried out a theoretical and numerical analysis for an epidemic model to analyze the dynamics of the SARS-CoV-2 Omicron variant and the impact of vaccination campaigns in the United States. The model proposed here includes asymptomatic and hospitalized compartments, vaccination with booster doses, and the waning of natural and vaccine-acquired immunity. We also consider the influence of face mask usage and efficiency. We found that enhancing booster doses and using N95 face masks are associated with a reduction in the number of new infections, hospitalizations and deaths. We highly recommend the use of surgical face masks as well, if usage of N95 is not a possibility due to the price range. Our simulations show that there might be two upcoming Omicron waves (in mid-2022 and late 2022), caused by natural and acquired immunity waning with respect to time. The magnitude of these waves will be 53% and 25% lower than the peak in January 2022, respectively. Hence, we recommend continuing to use face masks to decrease the peak of the upcoming COVID-19 waves.

Harnessing the Immunological Effects of Radiation to Improve Immunotherapies in Cancer

Ionizing radiation (IR) is used to treat 50% of cancers. While the cytotoxic effects related to DNA damage with IR have been known since the early 20th century, the role of the immune system in the treatment response is still yet to be fully determined. IR can induce immunogenic cell death (ICD), which activates innate and adaptive immunity against the cancer. It has also been widely reported that an intact immune system is essential to IR efficacy. However, this response is typically transient, and wound healing processes also become upregulated, dampening early immunological efforts to overcome the disease. This immune suppression involves many complex cellular and molecular mechanisms that ultimately result in the generation of radioresistance in many cases. Understanding the mechanisms behind these responses is challenging as the effects are extensive and often occur simultaneously within the tumor. Here, we describe the effects of IR on the immune landscape of tumors. ICD, along with myeloid and lymphoid responses to IR, are discussed, with the hope of shedding light on the complex immune stimulatory and immunosuppressive responses involved with this cornerstone cancer treatment. Leveraging these immunological effects can provide a platform for improving immunotherapy efficacy in the future.

Antigen-specificity measurements are the key to understanding T cell responses

Antigen-specific T cells play a central role in the adaptive immune response and come in a wide range of phenotypes. T cell receptors (TCRs) mediate the antigen-specificities found in T cells. Importantly, high-throughput TCR sequencing provides a fingerprint which allows tracking of specific T cells and their clonal expansion in response to particular antigens. As a result, many studies have leveraged TCR sequencing in an attempt to elucidate the role of antigen-specific T cells in various contexts. Here, we discuss the published approaches to studying antigen-specific T cells and their specific TCR repertoire. Further, we discuss how these methods have been applied to study the TCR repertoire in various diseases in order to characterize the antigen-specific T cells involved in the immune control of disease.

The ins and outs of innate and adaptive type 2 immunity

Type 2 immunity is orchestrated by a canonical group of cytokines primarily produced by innate lymphoid cells, group 2, and their adaptive counterparts, CD4+ helper type 2 cells, and elaborated by myeloid cells and antibodies that accumulate in response. Here, we review the cytokine and cellular circuits that mediate type 2 immunity. Building from insights in cytokine evolution, we propose that innate type 2 immunity evolved to monitor the status of microbe-rich epithelial barriers (outside) and sterile parenchymal borders (inside) to meet the functional demands of local tissue, and, when necessary, to relay information to the adaptive immune system to reinforce demarcating borders to sustain these efforts. Allergic pathology likely results from deviations in local sustaining units caused by alterations imposed by environmental effects during postnatal developmental windows and exacerbated by mutations that increase vulnerabilities. This framework positions T2 immunity as central to sustaining tissue repair and regeneration and provides a context toward understanding allergic disease.

Contribution of adaptive immunity to human COPD and experimental models of emphysema

The pathophysiology of chronic obstructive pulmonary disease (COPD) and the undisputed role of innate immune cells in this condition have dominated the field in the basic research arena for many years. Recently, however, compelling data suggesting that adaptive immune cells may also contribute to the progressive nature of lung destruction associated with COPD in smokers have gained considerable attention. The histopathological changes in the lungs of smokers can be limited to the large or small airways, but alveolar loss leading to emphysema, which occurs in some individuals, remains its most significant and irreversible outcome. Critically, however, the question of why emphysema progresses in a subset of former smokers remained a mystery for many years. The recognition of activated and organized tertiary T- and B-lymphoid aggregates in emphysematous lungs provided the first clue that adaptive immune cells may play a crucial role in COPD pathophysiology. Based on these findings from human translational studies, experimental animal models of emphysema were used to determine the mechanisms through which smoke exposure initiates and orchestrates adaptive autoreactive inflammation in the lungs. These models have revealed that T helper (Th)1 and Th17 subsets promote a positive feedback loop that activates innate immune cells, confirming their role in emphysema pathogenesis. Results from genetic studies and immune-based discoveries have further provided strong evidence for autoimmunity induction in smokers with emphysema. These new findings offer a novel opportunity to explore the mechanisms underlying the inflammatory landscape in the COPD lung and offer insights for development of precision-based treatment to halt lung destruction.

Mechanistic insight into the protective and pathogenic immune-responses against SARS-CoV-2

COVID-19 is a severe respiratory illness that has emerged as a devasting health problem worldwide. The disease outcome is heterogeneous, which is most likely dependent on the immunity of an individual. Asymptomatic and mildly/moderate symptomatic (non-severe) patients likely develop an effective early immune response and clear the virus. However, severe symptoms dominate due to a failure in the generation of an effective and specific early immune response against SARS-CoV-2. Moreover, a late surge in pathogenic inflammation involves dysregulated innate and adaptive immune responses leading to local and systemic tissue damage and the emergence of severe disease symptoms. In this review, we describe the potential mechanisms of protective and pathogenic immune responses in "mild/moderate" and "severe" symptomatic SARS-CoV-2 infected people, respectively, and discuss the immune components that are currently targeted for therapeutic intervention.