Macrophage polarization to a unique phenotype driven by B cells

The role and research progress of macrophages after heart transplantation

Since the 60s of the 20th century, heart transplantation has been the best treatment for patients with end-stage heart failure. Due to the increasing number of patients, how to expand the number of donor organs and enhance immune compatibility has become an urgent problem to be solved at this stage. Although current immunosuppression is effective, its side effects are also quite obvious, such as opportunistic infections and malignant tumors. In this review, we focus on the important role in macrophages after heart transplantation and their potential targets for achieving allogeneic graft tolerance, in order to improve effective graft survival and reduce infection and the occurrence of malignant tumors.

The role of B-1 cells in cancer progression and anti-tumor immunity

In recent years, in addition to the well-established role of T cells in controlling or promoting tumor growth, a new wave of research has demonstrated the active involvement of B cells in tumor immunity. B-cell subsets with distinct phenotypes and functions play various roles in tumor progression. Plasma cells and activated B cells have been linked to improved clinical outcomes in several types of cancer, whereas regulatory B cells have been associated with disease progression. However, we are only beginning to understand the role of a particular innate subset of B cells, referred to as B-1 cells, in cancer. Here, we summarize the characteristics of B-1 cells and review their ability to infiltrate tumors. We also describe the potential mechanisms through which B-1 cells suppress anti-tumor immune responses and promote tumor progression. Additionally, we highlight recent studies on the protective anti-tumor function of B-1 cells in both mouse models and humans. Understanding the functions of B-1 cells in tumor immunity could pave the way for designing more effective cancer immunotherapies.

Upregulation of IL4-induced gene 1 enzyme by B2 cells during melanoma progression impairs their antitumor properties

B cells present in human cutaneous melanoma have been associated with protective or detrimental effects on disease progression according to their phenotype. By using the RET model of spontaneous melanoma and adoptive transfer of B16 melanoma cells, we show that immature and follicular B2 (B2-FO) cells exert a protective effect on melanoma progression by promoting the generation of effector memory T cells and limiting the recruitment of polymorphonuclear myeloid-derived suppressor cells. Unfortunately, this beneficial effect progressively wanes as a consequence of enhanced expression of the IL4-induced gene 1 (IL4I1) enzyme by immature B cells and B2-FO cells. Endogenous IL4I1 selectively decreases CXCR5 expression in splenic immature B cells, subverting their trafficking to primary tumors and enhancing the production of IL-10 by B2 cells, thereby promoting an immunosuppressive microenvironment. Accordingly, B2 cells from RET IL4I1KO mice more efficiently controlled B16 melanoma growth than B2 cells from IL4I1-competent RET mice. Collectively, immature B cells and B2-FO cells are key actors in the control of melanoma growth, but their mobility and functions are differently impaired by IL4I1 overexpression during melanoma progression. Thus, our present data strongly urge us to associate an IL4I1 antagonist with current immunotherapy to improve the treatment of metastatic melanoma.

scRNA-seq of colorectal cancer shows regional immune atlas with the function of CD20+ B cells

Colorectal cancer (CRC) from different regions exhibits different histological, genetic characteristics, and molecular subtypes, even in response to conventional chemotherapies and immunotherapies. To characterize the immune landscape in different regions of CRC and search for potential therapeutic targets, we analyzed 39,484 single-cell transcription data from 19 samples of CRC and paired normal tissues from four regions to identify the immune characteristics of CRC among anatomic locations, especially in B cells. We discovered that immune cell infiltration in tumors significantly varied among different regions of CRC. B cells from right- and left-sided CRC had different development trajectories, but both had extensive interactions with myeloid cells and T cells. Survival analysis suggested that CD20+ B cells correlated with good prognosis in CRC patients, especially on the right side. Furthermore, the depletion of CD20+ B cells demonstrated that anti-CD20 promoted tumor growth progression and reversed the tumor-killing activity of anti-PD-1 treatment in vivo and in vitro. Our results highlight the characterization of the immune landscape of CRC in different regions. CD20+ B-cell infiltration has been associated with CRC patient prognosis and may promote the tumor-killing role of PD-1 antibodies.

The promising role of tumor-associated macrophages in the treatment of cancer

Macrophages are important components of the immune system. Mature macrophages can be recruited to tumor microenvironment that affect tumor cell proliferation, invasion and metastasis, extracellular matrix remodeling, immune suppression, as well as chemotherapy resistance. Classically activated type I macrophages (M1) exhibited marked tumor killing and phagocytosis. Therefore, using macrophages for adoptive cell therapy has attracted attention and become one of the most effective strategies for cancer treatment. Through cytokines and/or chemokines, macrophage can inhibit myeloid cells recruitment, and activate anti-tumor and immune killing functions. Applying macrophages for anti-tumor delivery is one of the most promising approaches for cancer therapy. This review article introduces the role of macrophages in tumor development and drug resistance, and the possible clinical application of targeting macrophages for overcoming drug resistance and enhancing cancer therapeutics, as well as its challenges.

Immune cell networking in solid tumors: focus on macrophages and neutrophils

The tumor microenvironment is composed of tumor cells, stromal cells and leukocytes, including innate and adaptive immune cells, and represents an ecological niche that regulates tumor development and progression. In general, inflammatory cells are considered to contribute to tumor progression through various mechanisms, including the formation of an immunosuppressive microenvironment. Macrophages and neutrophils are important components of the tumor microenvironment and can act as a double-edged sword, promoting or inhibiting the development of the tumor. Targeting of the immune system is emerging as an important therapeutic strategy for cancer patients. However, the efficacy of the various immunotherapies available is still limited. Given the crucial importance of the crosstalk between macrophages and neutrophils and other immune cells in the formation of the anti-tumor immune response, targeting these interactions may represent a promising therapeutic approach against cancer. Here we will review the current knowledge of the role played by macrophages and neutrophils in cancer, focusing on their interaction with other immune cells.

Immune Cells in the Tumor Microenvironment of Soft Tissue Sarcomas

Soft tissue sarcomas (STSs) are a rare heterogeneous group of malignant neoplasms characterized by their aggressive course and poor response to treatment. This determines the relevance of research aimed at studying the pathogenesis of STSs. By now, it is known that STSs is characterized by complex relationships between the tumor cells and immune cells of the microenvironment. Dynamic interactions between tumor cells and components of the microenvironment enhance adaptation to changing environmental conditions, which provides the high aggressive potential of STSs and resistance to antitumor therapy. Today, active research is being conducted to find effective antitumor drugs and to evaluate the possibility of using therapy with immune cells of STS. The difficulty in assessing the efficacy of new antitumor options is primarily due to the high heterogeneity of this group of malignant neoplasms. Studying the role of immune cells in the microenvironment in the progression STSs and resistance to antitumor therapies will provide the discovery of new biomarkers of the disease and the prediction of response to immunotherapy. In addition, it will help to initially divide patients into subgroups of good and poor response to immunotherapy, thus avoiding wasting precious time in selecting the appropriate antitumor agent.

Hepatic macrophages play critical roles in the establishment and growth of hydatid cysts in the liver during Echinococcus granulosus sensu stricto infection

Cystic echinococcosis (CE) is a worldwide neglected zoonotic disease caused by infection with the larval stage of the tapeworm Echinococcus granulosus sensu lato (E. granulosus s.l.), which predominantly resides in the liver accompanied by mild inflammation. Macrophages constitute the main cellular component of the liver and play a central role in controlling the progression of inflammation and liver fibrosis. However, the role of hepatic macrophages in the establishment and growth of hydatid cysts in the liver during E. granulosus sensu stricto (E. granulosus s.s.) infection has not been fully elucidated. Here, we showed that CD68+ macrophages accumulated in pericystic areas of the liver and that the expression of CD163, a marker of anti-inflammatory macrophages, was more evident in active CE patients than in inactive CE patients. Moreover, in a mouse model of E. granulosus s.s. infection, the pool of hepatic macrophages expanded dramatically through the attraction of massive amounts of monocyte-derived macrophages (MoMFs) to the infection site. These infiltrating macrophages preferentially polarized toward an iNOS+ proinflammatory phenotype at the early stage and then toward a CD206+ anti-inflammatory phenotype at the late stage. Notably, the resident Kupffer cells (KCs) predominantly maintained an anti-inflammatory phenotype to favor persistent E. granulosus s.s. infection. In addition, depletion of hepatic macrophages promoted E. granulosus s.s. larval establishment and growth partially by inhibiting CD4+ T-cell recruitment and liver fibrosis. The above findings demonstrated that hepatic macrophages play a vital role in the progression of CE, contributing to a better understanding of the local inflammatory responses surrounding hydatid cysts and possibly facilitating the design of novel therapeutic approaches for CE.

Homeostatic role of B-1 cells in tissue immunity

To date, studies of tissue-resident immunity have mainly focused on innate immune cells and T cells, with limited data on B cells. B-1 B cells are a unique subset of B cells with innate-like properties, enriched in murine pleural and peritoneal cavities and distinct from conventional B-2 cells in their ontogeny, phenotype and function. Here we discuss how B-1 cells represent exemplar tissue-resident immune cells, summarizing the evidence for their long-term persistence & self-renewal within tissues, differential transcriptional programming shaped by organ-specific environmental cues, as well as their tissue-homeostatic functions. Finally, we review the emerging data supporting the presence and homeostatic role of B-1 cells across non-lymphoid organs (NLOs) both in mouse and human.

Revisiting macrophages in ovarian cancer microenvironment: development, function and interaction

Tumor-associated macrophages (TAMs) are an important component of the tumor microenvironment (TME) and have been linked to immunosuppression and poor prognosis. TAMs have been shown to be harmful in ovarian cancer (OC), with a positive correlation between their high levels of tumors and poor overall patient survival. These cells are crucial in the progression and chemoresistance of OC. The primary pro-tumoral role of TAMs is the release of cytokines, chemokines, enzymes, and exosomes that directly enhance the invasion potential and chemoresistance of OC by activating their pro-survival signalling pathways. TAMs play a crucial role in the metastasis of OC in the peritoneum and ascities by assisting in spheroid formation and cancer cell adhesion to the metastatic regions. Furthermore, TAMs interact with tumor protein p53 (TP53), exosomes, and other immune cells, such as stem cells and cancer-associated fibroblasts (CAFs) to support the progression and metastasis of OC. In this review we revisit development, functions and interactions of TAMs in the TME of OC patients to highlight and shed light on challenges and excitement down the road.

MCP-1/IL-12 ratio expressions correlated with adventitial collagen depositions in renal vessels and IL-4/IFN-γ expression correlated with interstitial collagen depositions in the kidneys of dogs with canine leishmaniasis

Collagen deposition is a common event in chronic inflammation, and canine Leishmaniosis (CanL) is generally associated with a long and chronic evolution. Considering that the kidney shows fibrinogenic changes during CanL, and the balance of cytokines/chemokines regulates the profibrinogenic and antifibrinogenic immune responses differently, it can be hypothesized that the balance of cytokines/chemokines can be differentially expressed in the renal tissue in order to determine the expression of collagen depositions in the kidneys. This study aimed to measure collagen deposition and to evaluate cytokine/chemokine expressions in the kidney by means of qRT-PCR in sixteen Leishmania-infected dogs and six uninfected controls. Kidney fragments were stained with hematoxylin & eosin (H&E), Masson's Trichrome, Picrosirius Red, and Gomori's reticulin. Intertubular and adventitial collagen depositions were evaluated by the morphometric approach. Cytokine RNA expressions were measured by means of qRT-PCR to identify molecules involved in chronic collagen depositions in kidneys with CanL. Collagen depositions were related to the presence of clinical signs, and more intense intertubular collagen depositions occurred in infected dogs. Adventitial collagen deposition, as morphometrically measured by the average area of the collagen, was more intense in clinically affected dogs than in subclinically infected dogs. TNF-α/TGF-β, MCP1/IL-12, CCL5/IL-12, IL-4/IFN-γ, and IL-12/TGF-β expressions were associated with clinical manifestations in dogs with CanL. The IL-4/IFN-α ratio was more commonly expressed and upregulated in clinically affected dogs, and downregulated in subclinically infected dogs. Furthermore, MCP-1/IL-12 and CCL5/IL-12 were more commonly expressed in subclinically infected dogs. Strong positive correlations were detected between morphometric values of interstitial collagen depositions and MCP-1/IL-12, IL-12, and IL-4 mRNA expression levels in the renal tissues. Adventitial collagen deposition was correlated with TGF-β, IL-4/IFN-γ, and TNF-α/TGF-β. In conclusion, our results showed the association of MCP-1/IL-12 and CCL5/IL-12 ratios with an absence of clinical signs, as well as an IL-4/IFN-α ratio with adventitial and intertubular collagen depositions in dogs with visceral leishmaniosis.

The role of macrophages-mediated communications among cell compositions of tumor microenvironment in cancer progression

Recent studies have revealed that tumor-associated macrophages are the most abundant stromal cells in the tumor microenvironment and play an important role in tumor initiation and progression. Furthermore, the proportion of macrophages in the tumor microenvironment is associated with the prognosis of patients with cancer. Tumor-associated macrophages can polarize into anti-tumorigenic phenotype (M1) and pro-tumorigenic phenotype (M2) by the stimulation of T-helper 1 and T-helper 2 cells respectively, and then exert opposite effects on tumor progression. Besides, there also is wide communication between tumor-associated macrophages and other immune compositions, such as cytotoxic T cells, regulatory T cells, cancer-associated fibroblasts, neutrophils and so on. Furthermore, the crosstalk between tumor-associated macrophages and other immune cells greatly influences tumor development and treatment outcomes. Notably, many functional molecules and signaling pathways have been found to participate in the interactions between tumor-associated macrophages and other immune cells and can be targeted to regulate tumor progression. Therefore, regulating these interactions and CAR-M therapy are considered to be novel immunotherapeutic pathways for the treatment of malignant tumors. In this review, we summarized the interactions between tumor-associated macrophages and other immune compositions in the tumor microenvironment and the underlying molecular mechanisms and analyzed the possibility to block or eradicate cancer by regulating tumor-associated macrophage-related tumor immune microenvironment.

Interaction Between Adipocytes and B Lymphocytes in Human Metabolic Diseases

Diseases associated with the disorders of carbohydrate and lipid metabolism are widespread in the modern world. Interaction between the cells of adipose tissue - adipocytes - and immune system cells is an essential factor in pathogenesis of such diseases. Long-term increase in the glucose and fatty acid levels leads to adipocyte hypertrophy and increased expression of pro-inflammatory cytokines and adipokines by these cells. As a result, immune cells acquire a pro-inflammatory phenotype, and new leukocytes are recruited. Inflammation of adipose tissue leads to insulin resistance and stimulates formation of atherosclerotic plaques and development of autoimmunity. New studies show that different groups of B lymphocytes play an essential role in regulation of adipose tissue inflammation. Decrease in the number of B-2 lymphocytes suppresses development of a number of metabolic diseases, whereas decreased numbers of the regulatory B lymphocytes and B-1 lymphocytes are associated with more severe pathology. Recent studies showed that adipocytes influence B lymphocyte activity both directly and by altering activity of other immune cells. These findings provide better understanding of the molecular mechanisms of human pathologies associated with impaired carbohydrate and lipid metabolism, such as type 2 diabetes mellitus.

The Role of B Lymphocyte Subsets in Adipose Tissue Development, Metabolism, and Aging

Adipose tissue contains resident B lymphocytes (B cells) with varying immune functions and mechanisms, depending on the adipose depot type and location. The heterogeneity of B cells and their functions affect the immunometabolism of the adipose tissue in aging and age-associated metabolic disorders. B cells exist in categorizations of subsets that have developmental or phenotypic differences with varying functionalities. Subsets can be categorized as either protective or pathogenic depending on their secretion profile or involvement in metabolic maintenance. In this article, we summarized recent finding on the B cell heterogeneity and discuss how we can utilize our current knowledge of adipose resident B lymphocytes for potential treatment for age-associated metabolic disorders. © 2022 American Physiological Society. Compr Physiol 12: 1-13, 2022.

Ibrutinib in the Treatment of Solid Tumors: Current State of Knowledge and Future Directions

Bruton's Tyrosine Kinase (BTK) is considered crucial in the activation and survival of both physiological and malignant B-cells. In recent years, ibrutinib, an oral BTK inhibitor, became a breakthrough therapy for hematological malignancies, such as chronic lymphocytic. However, ibrutinib's feasibility might not end there. Several other kinases with established involvement with solid malignancies (i.e., EGFR, HER2) have been found to be inhibited by this agent. Recent discoveries indicate that BTK is a potential anti-solid tumor therapy target. Consequently, ibrutinib, a BTK-inhibitor, has been studied as a therapeutic option in solid malignancies. While most preclinical studies indicate ibrutinib to be an effective therapeutic option in some specific indications, such as NSCLC and breast cancer, clinical trials contradict these observations. Nevertheless, while ibrutinib failed as a monotherapy, it might become an interesting part of a multidrug regime: not only has a synergism between ibrutinib and other compounds, such as trametinib or dactolisib, been observed in vitro, but this BTK inhibitor has also been established as a radio- and chemosensitizer. This review aims to describe the milestones in translating BTK inhibitors to solid tumors in order to understand the future potential of this agent better.

High-Dimensional Analysis Reveals Distinct Endotypes in Patients With Idiopathic Inflammatory Myopathies

The idiopathic inflammatory myopathies (IIM) are a rare clinically heterogeneous group of conditions affecting the skin, muscle, joint, and lung in various combinations. While myositis specific autoantibodies are well described, we postulate that broader immune endotypes exist in IIM spanning B cell, T cell, and monocyte compartments. This study aims to identify immune endotypes through detailed immunophenotyping of peripheral blood mononuclear cells (PBMCs) in IIM patients compared to healthy controls. We collected PBMCs from 17 patients with a clinical diagnosis of inflammatory myositis and characterized the B, T, and myeloid cell subsets using mass cytometry by time of flight (CyTOF). Data were analyzed using a combination of the dimensionality reduction algorithm t-distributed stochastic neighbor embedding (t-SNE), cluster identification, characterization, and regression (CITRUS), and marker enrichment modeling (MEM); supervised biaxial gating validated populations identified by these methods to be differentially abundant between groups. Using these approaches, we identified shared immunologic features across all IIM patients, despite different clinical features, as well as two distinct immune endotypes. All IIM patients had decreased surface expression of RP105/CD180 on B cells and a reduction in circulating CD3+CXCR3+ subsets relative to healthy controls. One IIM endotype featured CXCR4 upregulation across all cellular compartments. The second endotype was hallmarked by an increased frequency of CD19+CD21loCD11c+ and CD3+CD4+PD1+ subsets. The experimental and analytical methods we describe here are broadly applicable to studying other immune-mediated diseases (e.g., autoimmunity, immunodeficiency) or protective immune responses (e.g., infection, vaccination).

Immunosuppressive niche engineering at the onset of human colorectal cancer

The evolutionary dynamics of tumor initiation remain undetermined, and the interplay between neoplastic cells and the immune system is hypothesized to be critical in transformation. Colorectal cancer (CRC) presents a unique opportunity to study the transition to malignancy as pre-cancers (adenomas) and early-stage cancers are frequently resected. Here, we examine tumor-immune eco-evolutionary dynamics from pre-cancer to carcinoma using a computational model, ecological analysis of digital pathology data, and neoantigen prediction in 62 patient samples. Modeling predicted recruitment of immunosuppressive cells would be the most common driver of transformation. As predicted, ecological analysis reveals that progressed adenomas co-localized with immunosuppressive cells and cytokines, while benign adenomas co-localized with a mixed immune response. Carcinomas converge to a common immune "cold" ecology, relaxing selection against immunogenicity and high neoantigen burdens, with little evidence for PD-L1 overexpression driving tumor initiation. These findings suggest re-engineering the immunosuppressive niche may prove an effective immunotherapy in CRC.

Role of macrophages in tumor progression and therapy (Review)

The number and phenotype of macrophages are closely related to tumor growth and prognosis. Macrophages are recruited to (and polarized at) the tumor site thereby promoting tumor growth, stimulating tumor angiogenesis, facilitating tumor cell migration, and creating a favorable environment for subsequent colonization by (and survival of) tumor cells. These phenomena contribute to the formation of an immunosuppressive tumor microenvironment (TME) and therefore speed up tumor cell proliferation and metastasis and reduce the efficacy of antitumor factors and therapies. The ability of macrophages to remodel the TME through interactions with other cells and corresponding changes in their number, activity, and phenotype during conventional therapies, as well as the association between these changes and drug resistance, make tumor-associated macrophages a new target for antitumor therapies. In this review, advantages and limitations of the existing antitumor strategies targeting macrophages in Traditional Chinese and Western medicine were analyzed, starting with the effect of macrophages on tumors and their interactions with other cells and then the role of macrophages in conventional treatments was explored. Possible directions of future developments in this field from an all-around multitarget standpoint were also examined.

Leveraging macrophages for cancer theranostics

As fundamental immune cells in innate and adaptive immunity, macrophages engage in a double-edged relationship with cancer. Dissecting the character of macrophages in cancer development facilitates the emergence of macrophages-based new strategies that encompass macrophages as theranostic targets/tools of interest for treating cancer. Herein, we provide a concise overview of the mixed roles of macrophages in cancer pathogenesis and invasion as a foundation for the review discussions. We survey the latest progress on macrophage-based cancer theranostic strategies, emphasizing two major strategies, including targeting the endogenous tumor-associated macrophages (TAMs) and engineering the adoptive macrophages to reverse the immunosuppressive environment and augment the cancer theranostic efficacy. We also discuss and provide insights on the major challenges along with exciting opportunities for the future of macrophage-based cancer theranostic approaches.

Therapeutic Approaches Targeting Proteins in Tumor-Associated Macrophages and Their Applications in Cancers

Tumor-associated macrophages (TAMs) promote tumor proliferation, invasion, angiogenesis, stemness, therapeutic resistance, and immune tolerance in a protein-dependent manner. Therefore, the traditional target paradigms are often insufficient to exterminate tumor cells. These pro-tumoral functions are mediated by the subsets of macrophages that exhibit canonical protein markers, while simultaneously having unique transcriptional features, which makes the proteins expressed on TAMs promising targets during anti-tumor therapy. Herein, TAM-associated protein-dependent target strategies were developed with the aim of either reducing the numbers of TAMs or inhibiting the pro-tumoral functions of TAMs. Furthermore, the recent advances in TAMs associated with tumor metabolism and immunity were extensively exploited to repolarize these TAMs to become anti-tumor elements and reverse the immunosuppressive tumor microenvironment. In this review, we systematically summarize these current studies to fully illustrate the TAM-associated protein targets and their inhibitors, and we highlight the potential clinical applications of targeting the crosstalk among TAMs, tumor cells, and immune cells in anti-tumor therapy.

The Spatial Context of Tumor-Infiltrating Immune Cells Associates with Improved Ovarian Cancer Survival

Ovarian cancer is the deadliest gynecologic malignancy. Multi-omics techniques have provided a platform for improved predictive modeling of therapy response and patient outcomes. While high-grade serous carcinoma (HGSOC) tumors are immunogenic and numerous studies have defined positive correlation to immune cell infiltration, immunotherapies in clinical trials have exhibited low efficacy rates. There is a significant need to better comprehend the role and composition of immune cells in mediating ovarian cancer therapeutic response and progression. We performed multiplex IHC with an HGSOC tissue microarray (n = 127) to characterize the immune cell composition within tumors. After analyzing the composition and spatial context of T cells (CD4/CD8), macrophages (CD68), and B cells (CD19) within the tumor, we found that increased B-cell and CD4 T-cell presence correlated with overall survival. More importantly, we observed that the proximity between tumor-associated macrophages and B cells or CD4 T cells significantly correlated with overall survival. IMPLICATIONS: The results highlight the antitumor role of B cells and CD4 T cells, and that the spatial interactions between immune cell types are a novel predictor of therapeutic response and patient outcomes.

Response to FEC Chemotherapy and Oncolytic HSV-1 Is Associated with Macrophage Polarization and Increased Expression of S100A8/A9 in Triple Negative Breast Cancer

Simple Summary

We have previously reported that a combination of clinical chemotherapies and oncolytic HSV-1 works to sensitize tumors to respond to immune checkpoint blockade. We further showed that this therapeutic platform worked via the upregulation of B cells and the concomitant control of immunosuppressive myeloid cells. In this manuscript, we sought to further dissect the mechanism of myeloid cell regulation and differentiation and to identify a therapeutically driven gene signature that is associated with the switch in the myeloid phenotype. This work not only impacts triple-negative breast cancer but all solid tumor phenotypes as we aim to better understand the underlying immunology associated with responses to immune checkpoint therapies in these typically refractory disease types.

Abstract

The era of immunotherapy has seen an insurgence of novel therapies driving oncologic research and the clinical management of the disease. We have previously reported that a combination of chemotherapy (FEC) and oncolytic virotherapy (oHSV-1) can be used to sensitize otherwise non-responsive tumors to immune checkpoint blockade and that tumor-infiltrating B cells are required for the efficacy of our therapeutic regimen in a murine model of triple-negative breast cancer. In the studies herein, we have performed gene expression profiling using microarray analyses and have investigated the differential gene expression between tumors treated with FEC + oHSV-1 versus untreated tumors. In this work, we uncovered a therapeutically driven switch of the myeloid phenotype and a gene signature driving increased tumor cell killing.

The Role of B Cells in Head and Neck Cancer

Simple Summary

Host immunity has established its role in deciding the course of cancer evolution. As cellular and molecular components in the tumor microenvironment peripherally appear to be at a constant interplay, favoring either tumor control or progression, it is vital to decrypt the immunity elements, which demonstrate the potential to be harnessed towards cancer elimination. Head and neck cancer has been characterized as densely immune infiltrated but at the same time a highly immunosuppressive malignancy due to a negative equilibrium between active and dysfunctional immune cell populations. B-cells constitute the cornerstone of humoral immunity; however, their role in cancer has been vastly overlooked in comparison to other immune subtypes and reports from multiple studies fail to show agreement on their prognostic impact. This review focuses on the role of B-cells on head and neck cancer with the aim to highlight their effect on anti-cancer immunity, as well as their possible impact on immunotherapy outcomes.

Abstract

Head and neck cancer comprises a heterogenous, highly immune infiltrated malignancy, defined by a predominantly immunosuppressive tumor microenvironment (TME). In recent years, PD-1/PD-L1 immune checkpoint inhibitors have become the standard of care treatment, either as monotherapy or in combination with chemotherapy agents, thus revolutionizing the therapeutic landscape of recurrent/metastatic disease. As a result, preclinical research is increasingly focusing on TME composition and pathophysiology, aiming to comprehensively characterize the specific elements and interactions affecting anti-tumor immunity, as well as to unveil novel predictive biomarkers of immunotherapy outcomes. While T lymphocytic populations have been vastly explored regarding their effect on cancer development, B-cells constitute a far less investigated, yet possibly equally important, aspect of cancer immunity. B-cell presence, either as single cells or as part of tertiary lymphoid structures within the TME, has been associated with several anti-tumor defense mechanisms, such as antigen presentation, antibody production and participation in antibody-dependent cellular cytotoxicity, and has demonstrated prognostic significance for multiple types of malignancies. However, immunoregulatory B-cell phenotypes have also been identified both peripherally and within malignant tissue, bearing inhibitory effects on numerous immune response processes. Consequently, B-cells and their subsets demonstrate the potential to become valuable cancer biomarkers and acquire a leading role in future therapeutic strategies.

CD19 and intraglandular CD163-positivity as prognostic indicators of pregnancy outcome in CD138-negative women with a previous fresh-embryo-transfer failure

Many factors impede embryonic implantation, and excluding obvious known factors such as chronic endometritis, the immune status of the endometrium may be related to pregnancy. Although an abundantly large number of immune cells infiltrate the endometrium during the secretory phase, whether these immune cells can be used as a predictor of prognosis in ART has not yet been clarified. In the present study we therefore retrospectively analyzed 97 CD138-negative women with a previous fresh-embryo-transfer failure. We assessed the expression of CD56+ uNK cells, CD16+ NK cells, CD57+ NK cells, CD68+ pan-macrophages, CD163+ M2 macrophages, CD4+T cells, CD8+T cells, FOXP3+ regulatory T cells, and CD19+ B cells in the endometrium by IHC to evaluate mid-luteal endometrial immune cells as prognostic indicators of pregnancy outcome in the next frozen-embryo-transfer cycle. CD19-positive cells and the intraglandular CD163-positivity rate increased significantly in the clinically non-pregnant group (0.47 % vs. 0.20 %, P =  0.021; 61 % vs. 30 %, P =  0.017). The ratios of CD4/CD8 were also higher in the non-pregnant group (1.96 vs. 1.45, P =  0.005).The area under the ROC curve of CD19 cell number alone, the intraglandular CD163-positivity alone, and CD19 number combined with the intraglandular CD163-positivity were 0.692 (95 % CI, 0.55-0.834), 0.661 (95 % CI, 0.514-0.809), and 0.748 (95 % CI, 0.614-0.882), respectively. The optimal cut-off value of CD19 was 0.464 %, and the clinical pregnancy rate and live-birth rate diminished significantly when the CD19 level was above this cut-off value. Our study suggests that CD19-positive cells and intraglandular CD163-positivity can be used as prognostic indicators of pregnancy outcome in CD138-negative patients who experienced first-fresh-embryo transfer failure.

Modulatory Effect of Intermittent Fasting on Adipose Tissue Inflammation: Amelioration of Cardiovascular Dysfunction in Early Metabolic Impairment

Cardiometabolic syndrome (CMS) is a cluster of maladaptive cardiovascular, renal, thrombotic, inflammatory, and metabolic disorders. It confers a high risk of cardiovascular mortality and morbidity. CMS is triggered by major shifts in lifestyle and dietary habits with increased consumption of refined, calorie-dense diets. Evidence indicates that diet-induced CMS is linked to Adipose tissue (AT) inflammation. This led to the proposal that adipose inflammation may be involved in metabolic derangements, such as insulin resistance and poor glycemic control, as well as the contribution to the inflammatory process predisposing patients to increased cardiovascular risk. Therefore, in the absence of direct pharmacological interventions for the subclinical phase of CMS, time restricted feeding regimens were anticipated to alleviate early metabolic damage and subsequent comorbidities. These regimens, referred to as intermittent fasting (IF), showed a strong positive impact on the metabolic state of obese and non-obese human subjects and animal models, positive AT remodeling in face of overnutrition and high fat diet (HFD) consumption, and improved CV outcomes. Here, we summarize the available evidence on the role of adipose inflammation in triggering cardiovascular impairment in the context of diet induced CMS with an emphasis on the involvement of perivascular adipose tissue. As well, we propose some possible molecular pathways linking intermittent fasting to the ameliorative effect on adipose inflammation and cardiovascular dysfunction under such circumstances. We highlight a number of targets, whose function changes in perivascular adipose tissue inflammation and could be modified by intermittent fasting acting as a novel approach to ameliorate the inflammatory status.

Boysenberry and apple juice concentrate reduced acute lung inflammation and increased M2 macrophage-associated cytokines in an acute mouse model of allergic airways disease

Bioactive compounds including anthocyanins and other polyphenols are associated with reduced lung inflammation and improved lung function in asthma and other lung diseases. This study investigated the effects of a Boysenberry and apple juice concentrate, high in cyanidin glycosides, ellagitannins, and chlorogenic acid, on a mouse model of allergic airways inflammation. Male C57BL/6J mice were orally gavaged with 2.5 mg/kg of total anthocyanins (TAC) from BerriQi® Boysenberry and apple juice concentrate (0.2 mg/kg human equivalent dose) or water control 1 hr before an acute intranasal ovalbumin (OVA) challenge and were gavaged again 2 days after the intranasal challenge. Consumption of BerriQi® Boysenberry and apple juice concentrate significantly decreased OVA-induced infiltrating eosinophils, neutrophils, and T cells in the lung, and mucous production. Quantification of gene expression for arginase (Arg1), chitinase 3-like 3 (Ym-1), found in inflammatory zone (Fizz1), which have been associated with an anti-inflammatory macrophage phenotype (M2), found significantly increased Arg1 expression in the lung in the Boysenberry and apple juice concentrate treatment group. There was also increased production of M2-associated cytokines C-X-C motif chemokine ligand (CXCL) 10 and C-C motif chemokine ligand (CCL) 4. These results suggest that consumption of BerriQi® Boysenberry and apple juice concentrate promoted a shift toward an anti-inflammatory environment within the lung leading to reduced immune cell infiltration and tissue damage.

Use of Cocultures for the Study of Cellular Interactions Influencing B-Cell Regulatory Functions

Although IL-10-producing B cells have been shown to play key roles in regulating immune responses involved in autoimmunity, inflammation, and cancer, the mechanisms at the base of the generation and maintenance of the pool of regulatory B cells are still poorly characterized. Several evidences show that the cross talk between B cells and other immune cell types promotes IL-10 production by B lymphocytes. Soluble mediators released into the microenvironment, together with direct cell-cell contact, are key signals in the process of regulatory B-cell development and differentiation. Here we describe the methods required to follow IL-10-producing B cells in MC- and MDSC-B-cell cocultures as examples of in vitro systems that induce the expansion of the regulatory B-cell population. These protocols can be also adapted for the study of other immune cell systems.

Adipose Tissue Immunomodulation: A Novel Therapeutic Approach in Cardiovascular and Metabolic Diseases

Adipose tissue is a critical regulator of systemic metabolism and bodily homeostasis as it secretes a myriad of adipokines, including inflammatory and anti-inflammatory cytokines. As the main storage pool of lipids, subcutaneous and visceral adipose tissues undergo marked hypertrophy and hyperplasia in response to nutritional excess leading to hypoxia, adipokine dysregulation, and subsequent low-grade inflammation that is characterized by increased infiltration and activation of innate and adaptive immune cells. The specific localization, physiology, susceptibility to inflammation and the heterogeneity of the inflammatory cell population of each adipose depot are unique and thus dictate the possible complications of adipose tissue chronic inflammation. Several lines of evidence link visceral and particularly perivascular, pericardial, and perirenal adipose tissue inflammation to the development of metabolic syndrome, insulin resistance, type 2 diabetes and cardiovascular diseases. In addition to the implication of the immune system in the regulation of adipose tissue function, adipose tissue immune components are pivotal in detrimental or otherwise favorable adipose tissue remodeling and thermogenesis. Adipose tissue resident and infiltrating immune cells undergo metabolic and morphological adaptation based on the systemic energy status and thus a better comprehension of the metabolic regulation of immune cells in adipose tissues is pivotal to address complications of chronic adipose tissue inflammation. In this review, we discuss the role of adipose innate and adaptive immune cells across various physiological and pathophysiological states that pertain to the development or progression of cardiovascular diseases associated with metabolic disorders. Understanding such mechanisms allows for the exploitation of the adipose tissue-immune system crosstalk, exploring how the adipose immune system might be targeted as a strategy to treat cardiovascular derangements associated with metabolic dysfunctions.

Cancer systems immunology

Tumor immunology is undergoing a renaissance due to the recent profound clinical successes of tumor immunotherapy. These advances have coincided with an exponential growth in the development of -omics technologies. Armed with these technologies and their associated computational and modeling toolsets, systems biologists have turned their attention to tumor immunology in an effort to understand the precise nature and consequences of interactions between tumors and the immune system. Such interactions are inherently multivariate, spanning multiple time and size scales, cell types, and organ systems, rendering systems biology approaches particularly amenable to their interrogation. While in its infancy, the field of 'Cancer Systems Immunology' has already influenced our understanding of tumor immunology and immunotherapy. As the field matures, studies will move beyond descriptive characterizations toward functional investigations of the emergent behavior that govern tumor-immune responses. Thus, Cancer Systems Immunology holds incredible promise to advance our ability to fight this disease.

Host defense mechanisms against Mycobacterium tuberculosis

Tuberculosis (TB), which is caused by Mycobacterium tuberculosis (Mtb), remains the leading cause of death worldwide from a single infectious pathogen. Mtb is a paradigmatic intracellular pathogen that primarily invades the lungs after host inhalation of bacteria-containing droplets via the airway. However, the majority of Mtb-exposed individuals can spontaneously control the infection by virtue of a robust immune defense system. The mucosal barriers of the respiratory tract shape the first-line defense against Mtb through various mucosal immune responses. After arriving at the alveoli, the surviving mycobacteria further encounter a set of host innate immune cells that exert multiple cellular bactericidal functions. Adaptive immunity, predominantly mediated by a range of different T cell and B cell subsets, is subsequently activated and participates in host anti-mycobacterial defense. During Mtb infection, host bactericidal immune responses are exquisitely adjusted and balanced by multifaceted mechanisms, including genetic and epigenetic regulation, metabolic regulation and neuroendocrine regulation, which are indispensable for maintaining host immune efficiency and avoiding excessive tissue injury. A better understanding of the integrated and equilibrated host immune defense system against Mtb will contribute to the development of rational TB treatment regimens especially novel host-directed therapeutics.

Effects of extracellular vesicles released by peritoneal B-1 cells on experimental Leishmania (Leishmania) amazonensis infection

B-1 cells are a B-lymphocyte subtype whose roles in immunity are not completely defined. These cells can produce cytokines (mainly IL-10) and natural and specific antibodies. Currently, extracellular vesicles (EVs) released by immune cells have emerged as new important entities in cell-cell communication. Immune cells release EVs that can activate and/or modulate other immune cells. Here, we characterized the EVs released by peritoneal B-1 cells infected or not with Leishmania (Leishmania) amazonensis. This Leishmania species causes cutaneous leishmaniasis and can infect macrophages and B-1 cells. Our results showed that peritoneal B-1 cells spontaneously release EVs, but the parasite stimulated an increase in EVs production by peritoneal B-1 cells. The treatment of BALB/c and C57BL/6 bone marrow-derived macrophages (BMDM) with EVs from infected peritoneal B-1 cells led to differential expression of iNOS, IL-6, IL-10, and TNF-α. Additionally, BALB/c mice previous treated with EVs released by peritoneal B-1 cells showed a significant lower lesion size and parasite burden. Thus, this study demonstrated that peritoneal B-1 cells could release EVs that can alter the functions of macrophages in vitro and in vivo these EVs altered the course of L. amazonensis infection. These findings represent the first evidence that EVs from peritoneal B-1 cells can act as a new mechanism of cellular communication between macrophages and B-1 cells, contributing to immunity against experimental leishmaniasis.

B Lymphocytes and Adipose Tissue Inflammation

The immune system plays an important role in obesity-induced adipose tissue inflammation and the resultant metabolic dysfunction, which can lead to hypertension, dyslipidemia, and insulin resistance and their downstream sequelae of type 2 diabetes mellitus and cardiovascular disease. While macrophages are the most abundant immune cell type in adipose tissue, other immune cells are also present, such as B cells, which play important roles in regulating adipose tissue inflammation. This brief review will overview B-cell subsets, describe their localization in various adipose depots and summarize our knowledge about the function of these B-cell subsets in regulating adipose tissue inflammation, obesity-induced metabolic dysfunction and atherosclerosis.

B-1 cell-mediated modulation of M1 macrophage profile ameliorates microbicidal functions and disrupt the evasion mechanisms of Encephalitozoon cuniculi

Here, we have investigated the possible effect of B-1 cells on the activity of peritoneal macrophages in E. cuniculi infection. In the presence of B-1 cells, peritoneal macrophages had an M1 profile with showed increased phagocytic capacity and index, associated with the intense microbicidal activity and a higher percentage of apoptotic death. The absence of B-1 cells was associated with a predominance of the M2 macrophages, reduced phagocytic capacity and index and microbicidal activity, increased pro-inflammatory and anti-inflammatory cytokines production, and higher percentual of necrosis death. In addition, in the M2 macrophages, spore of phagocytic E. cuniculi with polar tubular extrusion was observed, which is an important mechanism of evasion of the immune response. The results showed the importance of B-1 cells in the modulation of macrophage function against E. cuniculi infection, increasing microbicidal activity, and reducing the fungal mechanisms involved in the evasion of the immune response.

The adaptive immune response plays a key role against Encephalitozoon cuniculi, an opportunistic fungus for T cells immunodeficient patients. The role of B cells and antibody play in natural resistance to Encephalitozoon cuniculi remains unknown. Previously, we demonstrated that B-1 deficient mice (XID), an important component of innate immunity, were more susceptible to encephalitozoonosis, despite the increase in the number of CD4⁺ and CD8⁺ T lymphocytes. Here we observed that the absence of B-1 cells was associated with a larger population of M2 macrophages, a balance between anti-inflammatory and pro-inflammatory cytokines profile, which had lower microbicidal activity against E. cuniculi infection. However, in the presence of B-1 cells, peritoneal macrophages had a M1 profile with showed increased microbicidal activity and a higher percentage of apoptotic death.

Phenotypic identification of CD19+CD5+CD1d+ regulatory B cells that produce interleukin 10 and transforming growth factor β1 in human peripheral blood

INTRODUCTION

Regulatory B cells (Bregs), a novel subpopulation of B cells, are a significant area of research due to their immune regulatory function in the immunological response. Bregs have been reported to regulate acute inflammation and immunity through the production of anti-inflammatory cytokines.

MATERIAL AND METHODS

A B cell subpopulation was identified using flow cytometric analysis in two different processes: 1) after preparation and storage of peripheral blood mononuclear cells (PBMCs) using Ficoll density gradient centrifugation from a human blood sample, 2) followed by isolation and storage of B cells through magnetic separation using a B cell isolation kit and MS column. ELISA assays were performed to observe the cytokine production of interkleukin 10 (IL-10) and transforming growth factor β₁ (TGF-β₁) by this novel B cell subpopulation.

RESULTS

Double positive staining of CD5+CD1d+ Bregs represents (19.27 ±1.52) from PBMCs, (33.32 ±2.95) from B cells accordingly (n = 40). Through ELISA assays, it has been found that B cell subpopulation produces IL-10 (0.56 ±0.08) and TGF-β₁ (0.90 ±0.12) (n = 40).

CONCLUSIONS

These methods should be able to facilitate progress in research on Bregs through the following steps: 1) the regulatory role may be observed in comparison with particular autoimmune diseases, inflammation, cancer, and immunologic responses to find out whether Breg alteration and/or cytokine production is altered as well in these disorders or conditions. 2) If the alteration of Bregs and cytokine production is significant along with the clinical correlation, a further in vitro study can be initiated with exposure of certain drugs to overcome the alteration of the cytokine production; then, an in vivo study can be initiated.

B Cells Producing Type I IFN Modulate Macrophage Polarization in Tuberculosis

RATIONALE

In addition to their well-known function as antibody-producing cells, B lymphocytes can markedly influence the course of infectious or noninfectious diseases via antibody-independent mechanisms. In tuberculosis (TB), B cells accumulate in lungs, yet their functional contribution to the host response remains poorly understood.

OBJECTIVES

To document the role of B cells in TB in an unbiased manner.

METHODS

We generated the transcriptome of B cells isolated from Mycobacterium tuberculosis (Mtb)-infected mice and validated the identified key pathways using in vitro and in vivo assays. The obtained data were substantiated using B cells from pleural effusion of patients with TB.

MEASUREMENTS AND MAIN RESULTS

B cells isolated from Mtb-infected mice displayed a STAT1 (signal transducer and activator of transcription 1)-centered signature, suggesting a role for IFNs in B-cell response to infection. B cells stimulated in vitro with Mtb produced type I IFN, via a mechanism involving the innate sensor STING (stimulator of interferon genes), and antagonized by MyD88 (myeloid differentiation primary response 88) signaling. In vivo, B cells expressed type I IFN in the lungs of Mtb-infected mice and, of clinical relevance, in pleural fluid from patients with TB. Type I IFN expression by B cells induced an altered polarization of macrophages toward a regulatory/antiinflammatory profile in vitro. In vivo, increased provision of type I IFN by B cells in a murine model of B cell-restricted Myd88 deficiency correlated with an enhanced accumulation of regulatory/antiinflammatory macrophages in Mtb-infected lungs.

CONCLUSIONS

Type I IFN produced by Mtb-stimulated B cells favors macrophage polarization toward a regulatory/antiinflammatory phenotype during Mtb infection.

A Mixture of Polyunsaturated Fatty Acids ω-3 and ω-6 Reduces Melanoma Growth by Inhibiting Inflammatory Mediators in the Murine Tumor Microenvironment

Background: Although it has been previously demonstrated that acute inflammation can promote the tumor growth of a sub-tumorigenic dose of melanoma cells through of 5-lipoxygenase inflammatory pathway and its product leukotriene B_4, and also that the peritumoral treatment with eicosapentaenoic acid and its product, leukotriene B₅, reduces the tumor development, the effect of the treatment by gavage with omega-3 and omega-6 in the tumor microenvironment favorable to melanoma growth associated with acute inflammation has never been studied. Methods: C57BL/6 mice were coinjected with 1 × 10⁶ apoptotic cells plus 1 × 10³ viable melanoma cells into the subcutaneous tissue and treated by gavage with omega-3-rich fish oil or omega-6-rich soybean oil or a mixture of these oils (1:1 ratio) during five consecutive days. Results: The treatment by gavage with a mixture of fish and soybean oils (1:1 ratio) both reduced the melanoma growth and the levels of leukotriene B₄ (LTB₄), prostaglandin E₂ (PGE₂), PGE₂/prostaglandin E₃ (PGE₃) ratio, and CXC ligand 1 (CXCL1) and increased the levels of interleukin 10 (IL-10) to IL-10/CXCL1 ratio in the melanoma microenvironment. Conclusion: The oral administration of a 1:1 mixture of fish oil and soybean oil was able to alter the release of inflammatory mediators that are essential for a microenvironment favorable to the melanoma growth in mice, whereas fish oil or soybean oil alone was ineffective.

TGF-β Secretion by M2 Macrophages Induces Glial Scar Formation by Activating Astrocytes In Vitro

Transforming growth factor-β (TGF-β) is a key factor that promotes fibrosis or scar formation, which could become an obstacle in the repair of impaired axons in the central nervous system (CNS) of the human body resulting from diseases or injuries. Considering that major pathological reactions occur during this process, we focused on TGF-secreting M2 macrophages to identify the interactions between M2 macrophages and astrocytes (AS) and verify the specific mechanism of fibrosis or glial scar formation. In the present study, we used the Transwell coculturing technique and found an increase in glial fibrillary acidic protein (GFAP), neurocan, IL-13, and TGF-β expression after incubation for 48 h; the expression of these proteins decreased when additional inhibitors of the TGF-β receptor were added. We concluded that fibrosis or glial scar formation would be enhanced by the secretion of neurocan from AS, resulting from the release of TGF-β from M2 macrophages. We also used M2 macrophage-conditioned medium to further confirm this finding in a subsequent experiment. We hope that the findings in this research could provide a foundation for locating new targets for treating CNS diseases or injuries.

Emerging Roles for Immune Cells and MicroRNAs in Modulating the Response to Cardiac Injury

Stimulating cardiomyocyte regeneration after an acute injury remains the central goal in cardiovascular regenerative biology. While adult mammals respond to cardiac damage with deposition of rigid scar tissue, adult zebrafish and salamander unleash a regenerative program that culminates in new cardiomyocyte formation, resolution of scar tissue, and recovery of heart function. Recent studies have shown that immune cells are key to regulating pro-inflammatory and pro-regenerative signals that shift the injury microenvironment toward regeneration. Defining the genetic regulators that control the dynamic interplay between immune cells and injured cardiac tissue is crucial to decoding the endogenous mechanism of heart regeneration. In this review, we discuss our current understanding of the extent that macrophage and regulatory T cells influence cardiomyocyte proliferation and how microRNAs (miRNAs) regulate their activity in the injured heart.

Molecular Interactions Between Innate and Adaptive Immune Cells in Chronic Lymphocytic Leukemia and Their Therapeutic Implications

Innate immunity constitutes the first line of host defense against various anomalies in humans, and it also guides the adaptive immune response. The function of innate immune components and adaptive immune components are interlinked in hematological malignancies including chronic lymphocytic leukemia (CLL), and molecular interactions between innate and adaptive immune components are crucial for the development, progression and the therapeutic outcome of CLL. In this leukemia, genetic mutations in B cells and B cell receptors (BCR) are key driving factors along with evasion of cytotoxic T lymphocytes and promotion of regulatory T cells. Similarly, the release of various cytokines from CLL cells triggers the protumor phenotype in macrophages that further edges the CLL cells. Moreover, under the influence of various cytokines, dendritic cells are unable to mature and trigger T cell mediated antitumor response. The phenotypes of these cells are ultimately controlled by respective signaling pathways, the most notables are BCR, Wnt, Notch, and NF-κB, and their activation affects the cytokine profile that controls the pathogenesis of CLL, and challenge its treatment. There are several novel substances for CLL under clinical development, including kinase inhibitors, antibodies, and immune-modulators that offer new hopes. DC-based vaccines and CAR T cell therapy are promising tools; however, further studies are required to precisely dissect the molecular interactions among various molecular entities. In this review, we systematically discuss the involvement, common targets and therapeutic interventions of various cells for the better understanding and therapy of CLL.

EGFR Cooperates with EGFRvIII to Recruit Macrophages in Glioblastoma

: Amplification of the EGFR gene and its truncation mutant EGFRvIII are hallmarks of glioblastoma. Although coexpression of EGFR and EGFRvIII confers a growth advantage, how EGFR and EGFRvIII influence the tumor microenvironment remains incompletely understood. Here, we show that EGFR and EGFRvIII cooperate to induce macrophage infiltration via upregulation of the chemokine CCL2. EGFRvIII was significantly enriched in glioblastoma patient samples with high CCL2, and knockout of CCL2 in tumors coexpressing EGFR and EGFRvIII led to decreased infiltration of macrophages. KRAS was a critical signaling intermediate for EGFR- and EGFRvIII-induced expression of CCL2. Our results illustrate how EGFR and EGFRvIII direct the microenvironment in glioblastoma. SIGNIFICANCE: Full-length EGFR and truncated EGFRvIII work through KRAS to upregulate the chemokine CCL2 and drive macrophage infiltration in glioblastoma.

B lymphocytes in anti-mycobacterial immune responses: Pathogenesis or protection?

The role of B cells and antibodies in tuberculosis (TB) immunity, protection and pathogenesis remain contradictory. The presence of organized B cell follicles close to active TB lesions in the lung tissue raises the question about the role of these cells in local host-pathogen interactions. In this short review, we summarize the state of our knowledge concerning phenotypes of B cells populating tuberculous lungs, their secretory activity, interactions with other immune cells and possible involvement in protective vs. pathogenic TB immunity.

Interleukin-10 Producing Regulatory B Cells Transformed CD4+CD25- Into Tregs and Enhanced Regulatory T Cells Function in Human Leprosy

Regulatory B cells (Bregs) are known to exhibit their regulatory functions through interleukin-10 (IL-10) cytokine which suppress inflammation. There are only a few studies explaining the phenotype and functioning of these cells in contribution to host immunity in leprosy. Here, we evaluated the role of IL-10 producing Bregs in the pathogenesis of leprosy and assessed their immunoregulatory effects on Tregs and effector T cells. We found an increased frequency of Bregs and increased expression of their immune modulatory molecules (IL-10, FoxP3, and PDL-1) in leprosy patients. The potential immunoregulatory mechanism of Bregs was also investigated using MACS sorted Teff (CD4⁺CD25⁻) and Treg (CD4⁺CD25⁺) cells were cocultured with Bregs to elucidate the effects of Bregs on effector T and regulatory T cells. Cell coculture results showed that purified Bregs cells from leprosy patients convert CD4⁺CD25⁻ cells into CD4⁺CD25⁺ cells. Cell coculture experiments also demonstrated that leprosy derived IL-10 producing Bregs enhance FoxP3 and PD-1 expression in Tregs and enhanced Tregs activity. Blocking of IL-10 receptor confirmed that IL-10 producing Breg has immunomodulatory effect on Tregs and effector T cells as effector T cells are not converted into Tregs and enhanced expression of FoxP3 and PD-1 was not observed on Tregs. Collectively, these findings demonstrate that IL-10 producing Breg cells play an important mechanism in controlling the immunopathogenesis of leprosy and have an immunomodulatory effect on Tregs and effector T cells. Our findings may pave way for novel targets of IL-10 producing Bregs for immunotherapy in leprosy patients.

The Role of Macrophage/B-Cell Interactions in the Pathophysiology of B-Cell Lymphomas

Macrophages (MPs) are heterogeneous, multifunctional, myeloid-derived leukocytes that are part of the innate immune system, playing wide-ranging critical roles in basic biological activities, including maintenance of tissue homeostasis involving clearance of microbial pathogens. Tumor-associated MPs (TAMs) are MPs with defined specific M2 phenotypes now known to play central roles in the pathophysiology of a wide spectrum of malignant neoplasms. Also, TAMs are often intrinsic cellular components of the essential tumor microenvironment (TME). In concert with lymphoid-lineage B and T cells at various developmental stages, TAMs can mediate enhanced tumor progression, often leading to poor clinical prognosis, at least partly through secretion of chemokines, cytokines, and various active proteases shown to stimulate tumor growth, angiogenesis, metastasis, and immunosuppression. Researchers recently showed that TAMs express certain key checkpoint-associated proteins [e.g., programmed cell death protein 1 (PD-1), programmed cell death-ligand 1 (PD-L1)] that appear to be involved in T-cell activation and that these proteins are targets of other specific checkpoint-blocking immunotherapies (anti-PD-1/PD-L1) currently part of new therapeutic paradigms for chemotherapy-resistant neoplasms. Although much is known about the wide spectrum and flexibility of MPs under many normal and neoplastic conditions, relatively little is known about the increasingly important interactions between MPs and B-lymphoid cells, particularly in the TME in patients with aggressive B-cell non-Hodgkin lymphoma (NHL-B). Normal and neoplastic lymphoid and myeloid cell/MP lineages appear to share many primitive cellular characteristics as well as transcriptional factor interactions in human and animal ontogenic studies. Such cells are capable of ectopic transcription factor-induced lineage reprogramming or transdifferentiation from early myeloid/monocytic lineages to later induce B-cell lymphomagenesis in experimental in vivo murine systems. Close cellular interactions between endogenous clonal neoplastic B cells and related aberrant myeloid precursor cells/MPs appear to be important interactive components of aggressive NHL-B that we discuss herein in the larger context of the putative role of B-cell/MP cellular lineage interactions involved in NHL-B pathophysiology during ensuing lymphoma development.

Ninjurin1 inhibits colitis-mediated colon cancer development and growth by suppression of macrophage infiltration through repression of FAK signaling

Macrophage infiltration promotes tumorigenesis. However, the macrophage infiltration regulatory molecules have not been fully determined. Nerve injury-induced protein 1 (ninjurin1) is a homophilic cell surface adhesion molecule that plays an important role in cell migration and attachment. Although ninjurin1 is believed to play a role in several malignancies, it is unclear whether ninjurin1 expression contributes to cancer progression. We used transgenic mice (tg mice) that overexpressed ninjurin1 on macrophages. We subjected ninjurin1 tg mice to a well-known mouse model of colitis-associated colon cancer in which animals are treated with azoxymethane (AOM) and dextran sulfate sodium (DSS). After AOM and DSS treatment, ninjurin1 tg mice developed fewer and smaller tumors compared with wild-type (wt) mice. Ninjurin1 tg mice also showed reduced infiltration of macrophages and suppressed angiogenesis in the tumor mass. We therefore explored whether ninjurin1 decreases macrophage migration into the tumor sites. After adoptive transfer to tumor-bearing recipients, wild type and ninjurin1 tg mice's peritoneal macrophages were freshly isolated and labeled with carboxyfluorescein succinimidyl ester (CFSE). As expected, compared with that of wt type macrophages, tumor infiltration of ninjurin1-overexpressing macrophages was significantly decreased. We also found that ninjurin1 overexpression suppressed FAK activity. In addition, knockdown of ninjurin1 enhanced FAK activity and migration activity of RAW264.7 cells. Ninjurin1 overexpression on macrophage inhibits tumor growth by suppression of macrophage infiltration through repression of FAK signaling. Ninjurin1 is a key regulator molecule for macrophage migration and Tumor-associated macrophages (TAM) mediated tumorigenesis in vivo.

Yin-yang regulating effects of cancer-associated genes, proteins, and cells: An ancient Chinese concept in vogue in modern cancer research

Great achievements have been made in human cancer research, but most of this research is focused on conditions at the microscopic rather than the systemic level. Recent studies have increasingly cited the ancient Chinese theory of yin-yang in an effort to expand beyond the microscopic level. Various cancer-associated genes and proteins such as mitogen-activated protein kinase (MAPK), p38, p53, c-Myc, tumor necrosis factor (TNF)-α, NF-κB, Cyclin D1, and cyclin-dependent kinase (CDK) and cells such as T cells, B cells, macrophages, neutrophils, and fibroblasts have been reported to regulate various types of cancers in a yin-yang manner. These studies have brought the theory of yin-yang into vogue in cancer research worldwide.

HLA-mediated tumor escape mechanisms that may impair immunotherapy clinical outcomes via T-cell activation

Although the immune system provides protection from cancer by means of immunosurveillance, which serves a major function in eliminating cancer cells, it may also lead to cancer immunoediting, molding tumor immunogenicity. Cancer cells exploit several molecular mechanisms to thwart immune-mediated death by disabling cellular components of the immune system associated with tumor recognition and rejection. Human leukocyte antigen (HLA) molecules are mandatory for the immune recognition and subsequent killing of neoplastic cells by the immune system, as tumor antigens must be presented in an HLA-restricted manner to be recognized by T-cell receptors. Impaired HLA-I expression prevents the activation of cytotoxic immune mechanisms, whereas impaired HLA-II expression affects the antigen-presenting capability of antigen presenting cells. Aberrant HLA-G expression by cancer cells favors immune escape by inhibiting the activities of virtually all immune cells. The development of cancer therapies based on T-cell activation must consider these HLA-associated immune evasion mechanisms, as alterations in their expression occur early and frequently in the majority of types of cancer, and have an adverse impact on the clinical response to immunotherapy. Herein, the concept of altered HLA expression as a mechanism exploited by tumors to escape immune control and induce an immunosuppressive environment is reviewed. A number of novel clinical immunotherapeutic approaches used for cancer treatment are also reviewed, and strategies for overcoming the limitations of these immunotherapeutic interventions are proposed.

CCL5 Promotes Resolution-Phase Macrophage Reprogramming in Concert with the Atypical Chemokine Receptor D6 and Apoptotic Polymorphonuclear Cells

The engulfment of apoptotic polymorphonuclear cells (PMN) during the resolution of inflammation leads to macrophage reprogramming culminating in reduced proinflammatory and increased anti-inflammatory mediator secretion. The atypical chemokine receptor D6/ACKR2 is expressed on apoptotic PMN and plays an important role in regulating macrophage properties during and after engulfment. In this study, we found that the inflammatory chemokine CCL5 is mostly retained (75%) during the resolution of zymosan A peritonitis in mice. Moreover, this chemokine is secreted by resolution-phase macrophages (2.5 ng/ml) and promotes their reprogramming in vivo in D6+/+ mice (2-fold increase in IL-10/IL-12 ratio) but not their D6-/- counterparts. In addition, CCL5 enhanced macrophage reprogramming ex vivo exclusively when bound to D6+/+ apoptotic PMN. Signaling through p38MAPK and JNK in reprogrammed macrophages was enhanced by CCL5-bound apoptotic PMN (3.6-4 fold) in a D6-dependent manner, and was essential for reprogramming. Thus, CCL5 exerts a novel proresolving role on macrophages when acting in concert with apoptotic PMN-expressed D6.

Bruton's tyrosine kinase (BTK) as a promising target in solid tumors

Bruton's tyrosine kinase (BTK) is a non-receptor intracellular kinase that belongs to the TEC-family tyrosine kinases together with bone marrow-expressed kinase (BMX), redundant-resting lymphocyte kinase (RLK), and IL-2 inducible T-Cell kinase (ITK). All these proteins play a key role in the intracellular signaling of both B and T lymphocytes. Recently, some preclinical data have demonstrated that BTK is present in certain tumor subtypes and in other relevant cells that are contributing to the tumor microenvironment such as dendritic cells, macrophages, myeloid derived suppressor cells and endothelial cells. Ibrutinib (PCI-32765) is an orally available small molecule that acts as an inhibitor of the BTK and is approved for the treatment of patients with some hematological malignancies. It has been suggested that ibrutinib may also have a potential antitumor activity in solid neoplasms. In this sense, ibrutinib has the ability to revert polarization of TCD4+ to Th1 lymphocytes to increase the cytotoxic ability of T CD8+ and to regulate tumor-induced immune tolerance by acting over tumor infiltrating cells activity and immunosuppressive cytokines release. Furthermore, based on its molecular activity and safety, ibrutinib has been considered as a partner for treatment combination with PI3K/AKT/mTOR inhibitors or with immune-checkpoint inhibitors, inhibiting immunosuppressive signals from the tumor microenvironment, and overcoming the immune resistance to current anti-PD1/PDL1 immunotherapeutic drugs by the CXCR4/CXCL2 pathway regulation. Currently, a broad range of different studies are evaluating the activity of ibrutinib either as single agent or in combination in patients with solid tumors.