Understanding the complexity of γδ T-cell subsets in mouse and human

γδ T cells in malaria: a double-edged sword

Malaria remains a devastating global health problem, resulting in many annual deaths due to the complications of severe malaria. However, in endemic regions, individuals can acquire ‘clinical immunity’ to malaria, characterized by a decrease in severe malaria episodes and an increase of asymptomatic Plasmodium falciparum infections. Recently, it has been reported that tolerance to ‘clinical malaria’ and reduced disease severity correlates with a decrease in the numbers of circulating Vγ9Vδ2 T cells, the major subset of γδ T cells in the human peripheral blood. This is particularly interesting as this population typically undergoes dramatic expansions during acute Plasmodium infections and was previously shown to play antiparasitic functions. Thus, regulated γδ T‐cell responses may be critical to balance immune protection with severe pathology, particularly as both seem to rely on the same pro‐inflammatory cytokines, most notably TNF and IFN‐γ. This has been clearly demonstrated in mouse models of experimental cerebral malaria (ECM) based on Plasmodium berghei ANKA infection. Furthermore, our recent studies suggest that the natural course of Plasmodium infection, mimicked in mice through mosquito bite or sporozoite inoculation, includes a major pathogenic component in ECM that depends on γδ T cells and IFN‐γ production in the asymptomatic liver stage, where parasite virulence is seemingly set and determines pathology in the subsequent blood stage. Here, we discuss these and other recent advances in our understanding of the complex—protective versus pathogenic—functions of γδ T cells in malaria.

Role of Dendritic Epidermal T Cells in Cutaneous Carcinoma

Dendritic epidermal T cells (DETCs) are γδ T cells expressing invariant Vγ5Vδ1 T cell receptor (TCR) in murine epidermis. Initially, the development and the maturation of DETC progenitors are mediated by skint-1, TCR, and cytokines in the fetal thymus. Then, the DETC progenitors migrate to the epidermis with the guidance of selectins, CCR10, CCR4, etc. Eventually, mature DETCs proliferate and maintain a homeostatic population in the epidermis through IL-15 and aryl hydro-carbon receptor signaling. In “stressed” skin, DETCs are activated, exhibiting features such as a round morphology, cytotoxicity, and production of cytokines. In cutaneous carcinoma, DETCs generally inhibit tumor development directly in non-major histocompatibility complex-restricted manner, with the assistance of cytokines. DETCs also recognize and inhibit tumor via TCR, non-TCR receptors (such as 2B4 and NKG2D), or both. This study summarizes the biogenesis and the function of DETCs in cutaneous carcinoma and clarifies the essential surveillance role in the epidermis that DETCs play. As there are no DETCs in human epidermis but only human epidermis γδ T cells, we need to understand the anti-tumor pathways used by DETCs to find analogous immune pathways in human skin, which could be exploited for novel therapeutics.

Molecular Aspects and Future Perspectives of Cytokine-Based Anti-cancer Immunotherapy

Cytokine-based immunotherapy is a promising field in the cancer treatment, since cytokines, as proteins of the immune system, are able to modulate the host immune response toward cancer cell, as well as directly induce tumor cell death. Since a low dose monotherapy with some cytokines has no significant therapeutic results and a high dose treatment leads to a number of side effects caused by the pleiotropic effect of cytokines, the problem of understanding the influence of cytokines on the immune cells involved in the pro- and anti-tumor immune response remains a pressing one. Immune system cells carry CD makers on their surface which can be used to identify various populations of cells of the immune system that play different roles in pro- and anti-tumor immune responses. This review discusses the functions and specific CD markers of various immune cell populations which are reported to participate in the regulation of the immune response against the tumor. The results of research studies and clinical trials investigating the effect of cytokine therapy on the regulation of immune cell populations and their surface markers are also discussed. Current trends in the development of cancer immunotherapy, as well as the role of cytokines in combination with other therapeutic agents, are also discussed.

A transcriptome-based approach to identify functional modules within and across primary human immune cells

Genome-wide transcriptomic analyses have provided valuable insight into fundamental biology and disease pathophysiology. Many studies have taken advantage of the correlation in the expression patterns of the transcriptome to infer a potential biologic function of uncharacterized genes, and multiple groups have examined the relationship between co-expression, co-regulation, and gene function on a broader scale. Given the unique characteristics of immune cells circulating in the blood, we were interested in determining whether it was possible to identify functional co-expression modules in human immune cells. Specifically, we sequenced the transcriptome of nine immune cell types from peripheral blood cells of healthy donors and, using a combination of global and targeted analyses of genes within co-expression modules, we were able to determine functions for these modules that were cell lineage-specific or shared among multiple cell lineages. In addition, our analyses identified transcription factors likely important for immune cell lineage commitment and/or maintenance.

The Role of Human γδ T Cells in Anti-Tumor Immunity and Their Potential for Cancer Immunotherapy

γδ T cells are a distinct subset of T cells whose T cell receptors consist of γ chains and δ chains, different from conventional αβ T cells. γδ T cells are considered as a member of the innate immunity because of their non-MHC restricted antigen recognition, rapid response to invading pathogens and sense early changes of malignant cells. Upon activation, they can further promote the activation of adaptive immune cells, such as T cells and B cells, by secreting various cytokines. Thus, γδ T cells are regarded as a bridge between innate immunity and acquired immunity. γδ T cells are involved in a variety of immune response processes, including immune defense and immune surveillance against infection and tumorigenesis. γδ T cells recognize multiple tumor-associated antigens or molecules in T cell receptors (TCRs)-dependent and natural killer cell receptors (NKRs)-dependent ways. γδ T cells not only display a direct killing capacity on a variety of tumors, but also exert anti-tumor immune responses indirectly by facilitating the function of other immune cells, such as dendritic cells (DCs), B cells and CD8⁺ T cells. In this review, we summarize the major subpopulations, the tumor recognition mechanisms, and the anti-tumor effects of human γδ T cells, particularly the potential of γδ T cells for cancer immunotherapy.

The Aging of γδ T Cells

In the coming decades, many developed countries in the world are expecting the "greying" of their populations. This phenomenon poses unprecedented challenges to healthcare systems. Aging is one of the most important risk factors for infections and a myriad of diseases such as cancer, cardiovascular and neurodegenerative diseases. A common denominator that is implicated in these diseases is the immune system. The immune system consists of the innate and adaptive arms that complement each other to provide the host with a holistic defense system. While the diverse interactions between multiple arms of the immune system are necessary for its function, this complexity is amplified in the aging immune system as each immune cell type is affected differently-resulting in a conundrum that is especially difficult to target. Furthermore, certain cell types, such as γδ T cells, do not fit categorically into the arms of innate or adaptive immunity. In this review, we will first introduce the human γδ T cell family and its ligands before discussing parallels in mice. By covering the ontogeny and homeostasis of γδ T cells during their lifespan, we will better capture their evolution and responses to age-related stressors. Finally, we will identify knowledge gaps within these topics that can advance our understanding of the relationship between γδ T cells and aging, as well as age-related diseases such as cancer.

Electroporation of NKG2D RNA CAR Improves Vγ9Vδ2 T Cell Responses against Human Solid Tumor Xenografts

Vγ9Vδ2 T cell-based anticancer immunotherapy has shown some promise in early-phase clinical trials but there is still large room for improvement. Using the extracellular domain of the human NKG2D, a stimulatory receptor expressed by Vγ9Vδ2 T cells, we constructed NKG2D ligand-specific chimeric antigen receptors (CARs). We adopted a non-viral CAR approach via mRNA electroporation to modify Vγ9Vδ2 T cells and demonstrated that, upon interaction with the NKG2D ligand-positive cancer cells, the CARs substantially enhanced the cytotoxic activity of the modified cells toward multiple cultured solid tumor cell lines, including those resistant to Zometa treatment. Repeated doses of the CAR-expressing cells resulted in tumor regression in mice with established tumors, extending median survival time by up to 132% as compared to the PBS control group. The findings suggest clinical potential for RNA CAR-modified Vγ9Vδ2 T cells to treat a wide variety of NKG2D ligand-expressing cancers.

Revisiting the Interaction of γδ T-Cells and B-Cells

Right after the discovery of γδ T-cells in 1984, people started asking how γδ T-cells interact with other immune cells such as B-cells. Early reports showed that γδ T-cells are able to help B-cells to produce antibodies and to sustain the production of germinal centers. Interestingly, the presence of γδ T-cells seems to promote the generation of antibodies against "self" and less against challenging pathogens. More recently, these hypotheses were supported using γδ T-cell-deficient mouse strains, in different mouse models of systemic lupus erythematous, and after induction of epithelial cell damage. Together, these studies suggest that the link between γδ T-cells and the production of autoantibodies may be more relevant for the development of autoimmune diseases than generally acknowledged and thus targeting γδ T-cells could represent a new therapeutic strategy. In this review, we focus on what is known about the communication between γδ T-cells and B-cells, and we discuss the importance of this interaction in the context of autoimmunity.

Innate Lymphocytes in Psoriasis

Skin is a fundamental component of our host defense system that provides a dynamic physical and chemical barrier against pathogen invasion and environmental insults. Cutaneous barrier function is mediated by complex interactions between structural cells such as keratinocytes and diverse lineages of immune cells. In contrast to the protective role of these intercellular interactions, uncontrolled immune activation can lead to keratinocyte dysfunction and psoriasis, a chronic inflammatory disease affecting 2% of the global population. Despite some differences between human and murine skin, animal models of psoriasiform inflammation have greatly informed clinical approaches to disease. These studies have helped to identify the interleukin (IL)-23-IL-17 axis as a central cytokine network that drives disease. In addition, they have led to the recent description of long-lived, skin-resident innate lymphocyte and lymphoid cells that accumulate in psoriatic lesions. Although not completely defined, these populations have both overlapping and unique functions compared to antigen-restricted αβ T lymphocytes, the latter of which are well-known to contribute to disease pathogenesis. In this review, we describe the diversity of innate lymphocytes and lymphoid cells found in mammalian skin with a special focus on αβ T cells, Natural Killer T cells and Innate Lymphoid cells. In addition, we discuss the effector functions of these unique leukocyte subsets and how each may contribute to different stages of psoriasis. A more complete understanding of these cell types that bridge the innate and adaptive immune system will hopefully lead to more targeted therapies that mitigate or prevent disease progression.

Dissection of the Human T-Cell Receptor γ Gene Repertoire in the Brain and Peripheral Blood Identifies Age- and Alzheimer's Disease-Associated Clonotype Profiles

The immune system contributes to neurodegenerative pathologies. However, the roles of γδ T cells in Alzheimer's disease (AD) are poorly understood. Here, we evaluated somatic variability of T-cell receptor γ genes (TRGs) in patients with AD. We performed deep sequencing of the CDR3 region of TRGs in patients with AD and control patients without dementia. TRG clones were clearly detectable in peripheral blood (PB) and non-neuronal cell populations in human brains. TRG repertoire diversity was reduced during aging. Compared with the PB, the brain showed reduced TRGV9 clonotypes but was enriched in TRGV2/4/8 clonotypes. AD-associated TRG profiles were found in both the PB and brain. Moreover, some groups of clonotypes were more specific for the brain or blood in patients with AD compared to those in controls. Our pilot deep analysis of T-cell receptor diversities in AD revealed putative brain and AD-associated immunogenic markers.

Primary cutaneous γδ T-cell lymphoma with unusual immunophenotype: A case report and review of published work

Primary cutaneous γδ T-cell lymphoma (CGD-TCL) is a rare form of primary cutaneous lymphoma. The histopathological features of CGD-TCL are still unclear because of its rarity. Here, we report a case of a 77-year-old Japanese man who presented with a 9-month history of erythematous plaques on his left forearm. Skin biopsy specimens revealed the infiltration of atypical medium/large-sized lymphocytes from the epidermis to the deep dermis. Atypical lymphocytes were positive for CD3, CD5, CD8 and Vδ1, and negative for CD4, CD7, CD56, EBER-ISH, intracellular antigen-1, granzyme B and perforin. CD30 was partially expressed. We also reviewed 246 cases of CGD-TCL from the published work. CD4^- CD8^- double-negative cases were 113 of 196 cases (57.6%), followed by CD4^- CD8⁺ cases (52/196, 26.5%). CD5 was expressed in 25.8% of the cases (34/132). At least one cytotoxic molecule marker was expressed in 150 of 160 cases (93.8%). Some cases showed an indolent clinical course, especially in mycosis fungoides-like CGD-TCL cases. CD5 positivity and lack of cytotoxic molecule expression could be associated with a better prognosis. In addition, CD30 expression was found in approximately half of CGD-TCL cases (51/112 cases), suggesting that brentuximab vedotin could be a good treatment option for such patients. Further studies with more cases with detailed clinical and pathological information are necessary to elucidate the etiology and prognostic markers of this entity.

NKp46-expressing human gut-resident intraepithelial Vδ1 T cell subpopulation exhibits high antitumor activity against colorectal cancer

γδ T cells account for a large fraction of human intestinal intraepithelial lymphocytes (IELs) endowed with potent antitumor activities. However, little is known about their origin, phenotype, and clinical relevance in colorectal cancer (CRC). To determine γδ IEL gut specificity, homing, and functions, γδ T cells were purified from human healthy blood, lymph nodes, liver, skin, and intestine, either disease-free, affected by CRC, or generated from thymic precursors. The constitutive expression of NKp46 specifically identifies a subset of cytotoxic Vδ1 T cells representing the largest fraction of gut-resident IELs. The ontogeny and gut-tropism of NKp46+/Vδ1 IELs depends both on distinctive features of Vδ1 thymic precursors and gut-environmental factors. Either the constitutive presence of NKp46 on tissue-resident Vδ1 intestinal IELs or its induced expression on IL-2/IL-15-activated Vδ1 thymocytes are associated with antitumor functions. Higher frequencies of NKp46+/Vδ1 IELs in tumor-free specimens from CRC patients correlate with a lower risk of developing metastatic III/IV disease stages. Additionally, our in vitro settings reproducing CRC tumor microenvironment inhibited the expansion of NKp46+/Vδ1 cells from activated thymic precursors. These results parallel the very low frequencies of NKp46+/Vδ1 IELs able to infiltrate CRC, thus providing insights to either follow-up cancer progression or to develop adoptive cellular therapies.

Delayed gastrointestinal-associated lymphoid tissue reconstitution in duodenum compared with rectum in HIV-infected patients initiating antiretroviral therapy

BACKGROUND

We aimed to characterize the impact of antiretroviral therapy (ART) initiation on gastrointestinal-associated lymphoid tissue at various sites along the gastrointestinal site.

METHODOLOGY

Peripheral blood and duodenal and rectal biopsies were obtained from 12 HIV to 33 treatment-naive HIV participants at baseline and after 9 months ART. Tissue was digested for immunophenotyping. Inflammatory, bacterial translocation and intestinal damage markers were measured in plasma.

RESULTS

Twenty-six HIV patients completed follow-up. The lowest reconstitution of CD4 T cells and the lowest CD4/CD8 ratio during ART compared with blood were observed in the duodenum with the rectum being either intermediate or approaching blood levels. Regulatory T cells were in higher proportions in the duodenum than the rectum and neither declined significantly during ART. Several correlations with biomarkers of microbial translocation were observed including increases in lipoteichoic acid levels, which reflects Gram-positive bacterial translocation, correlated with increases in %CD4 T cells in the duodenum (Rho 0.773, P = 0.033), and with decreases in duodenal regulatory T-cell populations (Rho -0.40, P = 0.045).

CONCLUSION

HIV-mediated immunological disruption is greater in the duodenum than rectum and blood before and during ART. Small intestine damage may represent a unique environment for T-cell depletion, which might be attenuated by interaction with Gram-positive bacteria.

Tim-3 suppresses the killing effect of Vγ9Vδ2 T cells on colon cancer cells by reducing perforin and granzyme B expression

Gamma delta (γδ) T cell-based tumor immunotherapy has been one of the most promising cancer immunotherapeutic strategies. However, the key regulators of the Vγ9Vδ2 T cell-mediated antitumor response remain unclear. Recently, mounting reports have indicated that Tim-3 performs critical roles in the regulation of the activities of immune cells, including Vγ9Vδ2 T cells. However, the roles of Tim-3 in Vγ9Vδ2 T cell-mediated killing of colon cancer cells and the underlying mechanism remain largely unknown. Here, the proportion of Tim-3+ γδ T cells was significantly increased in both the peripheral blood and colon cancer tissue of patients and was significantly associated with TNM staging and tumor volume. Additionally, the activation of Tim-3 signaling significantly inhibited the killing efficiency of Vγ9Vδ2 T cells against colon cancer cells. In addition, Tim-3 signaling reduced the expression of perforin and granzyme B in Vγ9Vδ2 T cells. Blocking the perforin/granzyme B pathway also decreased the cytotoxicity of Vγ9Vδ2 T cells to colon cancer cells. Moreover, Tim-3 signaling reduced the perforin and granzyme B expression of Vγ9Vδ2 T cells in an ERK1/2 signaling pathway-dependent manner. This knowledge reveals that Tim-3 may be a promising therapeutic target to improve Vγ9Vδ2 T cell-based adoptive immunotherapy for colon cancer.

Guidelines for the use of flow cytometry and cell sorting in immunological studies (second edition)

These guidelines are a consensus work of a considerable number of members of the immunology and flow cytometry community. They provide the theory and key practical aspects of flow cytometry enabling immunologists to avoid the common errors that often undermine immunological data. Notably, there are comprehensive sections of all major immune cell types with helpful Tables detailing phenotypes in murine and human cells. The latest flow cytometry techniques and applications are also described, featuring examples of the data that can be generated and, importantly, how the data can be analysed. Furthermore, there are sections detailing tips, tricks and pitfalls to avoid, all written and peer-reviewed by leading experts in the field, making this an essential research companion.

Role of T-cell activation in salt-sensitive hypertension

The contributions of T lymphocytes to the pathogenesis of salt-sensitive hypertension has been well established. Under hypertensive stimuli, naive T cells develop into different subsets, including Th1, Th2, Th17, Treg, and cytotoxic CD8+ T cells, depending on the surrounding microenviroment in organs. Distinct subsets of T cells may play totally different roles in tissue damage and hypertension. The underlying mechanisms by which hypertensive stimuli activate naive T cells involve many events and different organs, such as neoantigen presentation by dendritic cells, high salt concentration, and the milieu of oxidative stress in the kidney and vasculature. Infiltrating and activated T subsets in injured organs, in turn, exert considerable impacts on tissue dysfunction, including sodium retention in the kidney, vascular stiffness, and remodeling in the vasculature. Therefore, a thorough knowledge of T-cell actions in hypertension may provide novel insights into the development of new therapeutic strategies for patients with hypertension.

Ex vivo expanded patient-derived γδ T-cell immunotherapy enhances neuroblastoma tumor regression in a murine model

An effective therapy regimen for relapsed/refractory high-risk neuroblastoma (NB) includes the anti-GD2 monoclonal antibody, dinutuximab, in combination with temozolomide and irinotecan, supporting a role for chemo-immunotherapy in NB. γδ T cells are an attractive anti-tumor immunotherapy because of their direct cytotoxic activity mediated through cell surface receptors NKG2D and CD16. NKG2D facilitates the innate recognition of stress-induced ligands whereas CD16 recognizes antibody bound to tumors and activates mechanisms of antibody-dependent cellular cytotoxicity (ADCC). This study demonstrates an efficient method for expanding and storing γδ T cells from NB patient-derived apheresis products at clinically relevant amounts. The expanded patient-derived γδ T cells were cytotoxic against the K562 cell line and multiple NB cell lines. Combining γδ T cells with dinutuximab led to a 30% increase in tumor cell lysis compared to γδ T cells alone. Furthermore, low-dose temozolomide in combination with expanded γδ T cells and dinutuximab resulted in increased IFNγ secretion and increased γδ T-cell surface expression of FasL and CD107a. IMR5 NB cell line xenografts established subcutaneously in NSG mice were treated with a regimen of dinutuximab, temozolomide, and γδ T cells. This combination caused targeted killing of NB xenografts in vivo, reducing tumor burden and prolonging survival. These data support the continued preclinical testing of dinutuximab and temozolomide in conjunction with γδ T-cell immunotherapy for patients with recurrent/refractory NB.

Expansion of different subpopulations of CD26-/low T cells in allergic and non-allergic asthmatics

CD26 displays variable levels between effector (TH₁₇ ≫ TH₁ > TH₂ > Treg) and naïve/memory (memory > naïve) CD4⁺ T lymphocytes. Besides, IL-6/IL⁻6R is associated with TH₁₇-differentiation and asthma severity. Allergic/atopic asthma (AA) is dominated by TH₂ responses, while TH₁₇ immunity might either modulate the TH₂-dependent inflammation in AA or be an important mechanism boosting non-allergic asthma (NAA). Therefore, in this work we have compared the expression of CD26 and CD126 (IL-6Rα) in lymphocytes from different groups of donors: allergic (AA) and non-allergic (NAA) asthma, rhinitis, and healthy subjects. For this purpose, flow cytometry, haematological/biochemical, and in vitro proliferation assays were performed. Our results show a strong CD26-CD126 correlation and an over-representation of CD26⁻ subsets with a highly-differentiated effector phenotype in AA (CD4⁺CD26^−/low T cells) and NAA (CD4⁻CD26⁻ γδ-T cells). In addition, we found that circulating levels of CD26 (sCD26) were reduced in both AA and NAA, while loss of CD126 expression on different leukocytes correlated with higher disease severity. Finally, selective inhibition of CD26-mRNA translation led to enhanced T cell proliferation in vitro. These findings support that CD26 down-modulation could play a role in facilitating the expansion of highly-differentiated effector T cell subsets in asthma.

IgG from Non-atopic Individuals Induces In Vitro IFN-γ and IL-10 Production by Human Intra-thymic γδT Cells: A Comparison with Atopic IgG and IVIg

Matured in the thymus, γδT cells can modulate the development of allergy in humans. The main γδT cell subsets have been described as interleukin (IL)-17A or interferon (IFN)-γ producers, but these cells can also produce other modulatory cytokines, such as IL-4 and IL-10. Here, we aimed to evaluate whether IgG can modulate the profile of cytokine production by γδT cells during their maturation in the thymus and after its migration to peripheral tissues. Thymic tissues were obtained from 12 infants, and peripheral blood mononuclear cells (PBMCs) were obtained from adults (both groups without an atopic background). IgG was purified from atopic and non-atopic volunteers. Thymocytes and PBMCs were cultured with purified atopic or non-atopic IgG, and intracellular cytokine production and phenotype were assessed. Mock and IVIg conditions were used as controls. IgG from non-atopic individuals induced IFN-γ and IL-10 production by thymic γδT cells, and no effect was observed on peripheral γδT cells. IL-17 production was inhibited by non-atopic IgG on thymic γδT cells and augmented by atopic IgG on peripheral γδT cells. Modulated thymic γδT cells did not produce IFN-γ and IL-10 simultaneously. We additionally evaluated the phenotype of intrathymic γδT cells and observed that IgG from all groups could induce CD25 expression and could not influence the CD28 expression of these cells. This report describes evidence revealing that IgG may influence the production of IFN-γ and IL-10 by intrathymic γδT cells depending on the donor atopic state. This observation is unprecedented and needs to be considered in further studies in the IgG immunotherapy field.

The Role of the Immune System in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common skin cancer. In immunosuppressed populations it is a source of considerable morbidity and mortality due to its enhanced recurrence and metastatic potential. In common with many malignancies, leucocyte populations are both protective against cancer development and also play a role in 'sculpting' the nascent tumor, leading to loss of immunogenicity and tumor progression. UV radiation and chronic viral carriage may represent unique risk factors for cSCC development, and the immune system plays a key role in modulating the response to both. In this review, we discuss the lessons learned from animal and ex vivo human studies of the role of individual leucocyte subpopulations in the development of cutaneous SCC. We then discuss the insights into cSCC immunity gleaned from studies in humans, particularly in populations receiving pharmacological immunosuppression such as transplant recipients. Similar insights in other malignancies have led to exciting and novel immune therapies, which are beginning to emerge into the cSCC clinical arena.

Immunotherapeutics in Multiple Myeloma: How Can Translational Mouse Models Help?

Multiple myeloma (MM) is usually diagnosed in older adults at the time of immunosenescence, a collection of age-related changes in the immune system that contribute to increased susceptibility to infection and cancer. The MM tumor microenvironment and cumulative chemotherapies also add to defects in immunity over the course of disease. In this review we discuss how mouse models have furthered our understanding of the immune defects caused by MM and enabled immunotherapeutics to progress to clinical trials, but also question the validity of using immunodeficient models for these purposes. Immunocompetent models, in particular the 5T series and Vk^⁎MYC models, are increasingly being utilized in preclinical studies and are adding to our knowledge of not only the adaptive immune system but also how the innate system might be enhanced in anti-MM activity. Finally we discuss the concept of immune profiling to target patients who might benefit the most from immunotherapeutics, and the use of humanized mice and 3D culture systems for personalized medicine.

Optimized protocols for γδ T cell expansion and lentiviral transduction

γδ T cells are a subset of unconventional T cells that serve a critical role in infectious diseases and various types of cancer. Cell therapy with genetically‑modified γδ T cells is regarded as a promising tool for tumor treatment. However, since γδ T cells constitute a minority of T cells, their large‑scale expansion is difficult to realize in an efficient and cost‑effective manner. In the present study, based on previous studies, culture protocols for γδ T cells were tested using different combinations of isopentenyl pyrophosphate and interleukin 2 in order to satisfy different experimental purposes. One protocol was demonstrated to be the most suitable for lentiviral transduction. These results greatly reinforce the promising prospects of using γδ T cells in basic research and for clinical applications.

γδ T lymphocytes in the pathogenesis of multiple sclerosis and experimental autoimmune encephalomyelitis

The aim of the current review is to summarize the results of studies on the role of γδ T cells in the pathogenesis of multiple sclerosis and its animal model - the experimental autoimmune encephalomyelitis. Despite the fact that numerous studies have been performed, the role of γδ T is still not fully understood. It seems that there are two distinct subpopulations - one exacerbating the disease (IL-17-producing) and the other playing a protective role (IFN-γ-secreting). Nevertheless, future studies are required for an understanding of γδ T cells role in multiple sclerosis.

Styk1 is specifically expressed in NK1.1+ lymphocytes including NK, γδ T, and iNKT cells in mice, but is dispensable for their ontogeny and function

Innate T cells, NK cells, and innate-like lymphocytes (ILCs) share transcriptional signatures that translate into overlapping developmental and functional programs. A prominent example for genes that are highly expressed in NK cells but not in ILCs is serine-threonine-tyrosine kinase 1 (Styk1 encoded by Styk1). We found Styk1 to be specifically expressed in lymphocytes positive for Killer cell lectin-like receptor subfamily B, member 1, also known as CD161 or NK1.1, i.e. in NK cell, αβ iNKT, and γδ NKT cell lineages. To investigate the role of Styk1 in the development and function of NK1.1⁺ innate T-cell subsets, we generated and analyzed a novel Styk1^null mutant mouse line. Furthermore, we validated Styk1 expression in γδ NKT cells and in thymic, but not in peripheral invariant αβ iNKT cells through ex vivo analysis of a concomitantly generated transgenic Styk1 reporter mouse line. Despite the very specific expression of Styk1 in NK cells, γδ NKT cells, and thymic αβ iNKT, its absence did not alter homeostasis and function of these lineages. Thus, Styk1 expression is specific for NK cells and selected NK-like innate T-cell subsets, but dispensable for their development and function.

Human Vδ1+ T Cells in the Immune Response to Plasmodium falciparum Infection

Naturally acquired protective immunity to Plasmodium falciparum malaria is mainly antibody-mediated. However, other cells of the innate and adaptive immune system also play important roles. These include so-called unconventional T cells, which express a γδ T-cell receptor (TCR) rather than the αβ TCR expressed by the majority of T cells—the conventional T cells. The γδ T-cell compartment can be divided into distinct subsets. One expresses a TCR involving Vγ9 and Vδ2, while another major subset uses instead a TCR composed of Vδ1 paired with one of several types of γ chains. The former of these subsets uses a largely semi-invariant TCR repertoire and responds in an innate-like fashion to pyrophosphate antigens generated by various stressed host cells and infectious pathogens, including P. falciparum. In this short review, we focus instead on the Vδ1 subset, which appears to have a more adaptive immunobiology, but which has been much less studied in general and in malaria in particular. We discuss the evidence that Vδ1⁺ cells do indeed play a role in malaria and speculate on the function and specificity of this cell type, which is increasingly attracting the attention of immunologists.

Evidence for Innate and Adaptive Immune Responses in a Cohort of Intractable Pediatric Epilepsy Surgery Patients

Brain-infiltrating lymphocytes (BILs) were isolated from resected brain tissue from 10 pediatric epilepsy patients who had undergone surgery for Hemimegalencephaly (HME) (n = 1), Tuberous sclerosis complex (TSC) (n = 2), Focal cortical dysplasia (FCD) (n = 4), and Rasmussen encephalitis (RE) (n = 3). Peripheral blood mononuclear cells (PBMCs) were also isolated from blood collected at the time of the surgery. Cells were immunostained with a panel of 20 antibody markers, and analyzed by mass cytometry. To identify and quantify the immune cell types in the samples, an unbiased clustering method was applied to the entire data set. More than 85 percent of the CD45+ cells isolated from resected RE brain tissue comprised T cells; by contrast NK cells and myeloid cells constituted 80-95 percent of the CD45+ cells isolated from the TSC and the FCD brain specimens. Three populations of myeloid cells made up >50 percent of all of the myeloid cells in all of the samples of which a population of HLA-DR+ CD11b+ CD4- cells comprised the vast majority of myeloid cells in the BIL fractions from the FCD and TSC cases. CD45RA+ HLA-DR- CD11b+ CD16+ NK cells constituted the major population of NK cells in the blood from all of the cases. This subset also comprised the majority of NK cells in BILs from the resected RE and HME brain tissue, whereas NK cells defined as CD45RA- HLA-DR+ CD11b- CD16- cells comprised 86-96 percent of the NK cells isolated from the FCD and TSC brain tissue. Thirteen different subsets of CD4 and CD8 αβ T cells and γδ T cells accounted for over 80% of the CD3+ T cells in all of the BIL and PBMC samples. At least 90 percent of the T cells in the RE BILs, 80 percent of the T cells in the HME BILs and 40-66 percent in the TSC and FCD BILs comprised activated antigen-experienced (CD45RO+ HLA-DR+ CD69+) T cells. We conclude that even in cases where there is no evidence for an infection or an immune disorder, activated peripheral immune cells may be present in epileptogenic areas of the brain, possibly in response to seizure-driven brain inflammation.

Changes of γδT cell subtypes during pregnancy and their influences in spontaneous abortion

A successful pregnancy is a complicated process that involves the precisely timed regulation of endocrine as well as immune system. Despite increasing knowledge about immunology in gestation, the studies of immune cells in endometrium and decidua are still fragmented. Dynamic data is lacking on the transition of pre-pregnancy endometrial lymphocytes to initial pregnancy states as well as to second/third-trimester status. Here, we determined the composition of Gamma delta (γδ) T cells in endometrium and decidua from women with normal pregnancy and unexplained spontaneous abortion. We found that the frequency of γδT cells is fluctuating over the course of pregnancy, and these changes were regulated by progesterone. Different from peripheral blood, Vδ1⁺ γδT cells accounted for the majority in endometrium and early-pregnancy decidua of healthy women, and endometrial stromal cells (ESCs) may involve in Vδ1/ Vδ2 shift directly. Moreover, an increase in the percentage of γδT cells with Vδ2 subset predominant in early-pregnancy decidua was associated with unexplained spontaneous abortion. Our results unraveled the precise timing of γδT cells occurring during pregnancy and the close relationship among endocrine, immune cells and pregnancy, which can further help understand and solve the problem of infertility and unexplained spontaneous abortion.

In Vivo PET Tracking of 89Zr-Labeled Vγ9Vδ2 T Cells to Mouse Xenograft Breast Tumors Activated with Liposomal Alendronate

Gammadelta T (γδ-T) cells are strong candidates for adoptive immunotherapy in oncology due to their cytotoxicity, ease of expansion, and favorable safety profile. The development of γδ-T cell therapies would benefit from non-invasive cell-tracking methods and increased targeting to tumor sites. Here we report the use of [89Zr]Zr(oxinate)4 to track Vγ9Vδ2 T cells in vivo by positron emission tomography (PET). In vitro, we showed that 89Zr-labeled Vγ9Vδ2 T cells retained their viability, proliferative capacity, and anti-cancer cytotoxicity with minimal DNA damage for amounts of 89Zr ≤20 mBq/cell. Using a mouse xenograft model of human breast cancer, 89Zr-labeled γδ-T cells were tracked by PET imaging over 1 week. To increase tumor antigen expression, the mice were pre-treated with PEGylated liposomal alendronate. Liposomal alendronate, but not placebo liposomes or non-liposomal alendronate, significantly increased the 89Zr signal in the tumors, suggesting increased homing of γδ-T cells to the tumors. γδ-T cell trafficking to tumors occurred within 48 hr of administration. The presence of γδ-T cells in tumors, liver, and spleen was confirmed by histology. Our results demonstrate the suitability of [89Zr]Zr(oxinate)4 as a cell-labeling agent for therapeutic T cells and the potential benefits of liposomal bisphosphonate treatment before γδ-T cell administration.

Gamma/Delta T Cells and Their Role in Protection Against Malaria

Whether and how γδT cells play a protective role in immunity against Plasmodium infection remain open questions. γδT cells expand in patients and mice infected with Plasmodium spp, and cytokine production and cytotoxic responses against blood-stage parasites are observed in vitro. Their expansion is associated with protective immunity induced by irradiated sporozoite immunization, and depletion of γδT cells in some mouse models of malaria excacerbates blood-stage infections. It is now clear that these cells can have many different functions, and data are emerging suggesting that in addition to having direct parasitocidal effects, they can regulate other immune cells during Plasmodium infections. Here we review some of the historic and more recent data on γδT cells, and in light of the new information on their potential protective roles we suggest that it is a good time to re-evaluate their activation requirements, specificity and function during malaria.

Metformin Promotes the Protection of Mice Infected With Plasmodium yoelii Independently of γδ T Cell Expansion

Adaptive immune responses are critical for protection against infection with Plasmodium parasites. The metabolic state dramatically changes in T cells during activation and the memory phase. Recent findings suggest that metformin, a medication for treating type-II diabetes, enhances T-cell immune responses by modulating lymphocyte metabolism. In this study, we investigated whether metformin could enhance anti-malaria immunity. Mice were infected with Plasmodium yoelii and administered metformin. Levels of parasitemia were reduced in treated mice compared with those in untreated mice, starting at ~2 weeks post-infection. The number of γδ T cells dramatically increased in the spleens of treated mice compared with that in untreated mice during the later phase of infection, while that of αβ T cells did not. The proportions of Vγ1⁺ and Vγ2⁺ γδ T cells increased, suggesting that activated cells were selectively expanded. However, these γδ T cells expressed inhibitory receptors and had severe defects in cytokine production, suggesting that they were in a state of exhaustion. Metformin was unable to rescue the cells from exhaustion at this stage. Depletion of γδ T cells with antibody treatment did not affect the reduction of parasitemia in metformin-treated mice, suggesting that the effect of metformin on the reduction of parasitemia was independent of γδ T cells.

Deciphering the Contribution of γδ T Cells to Outcomes in Transplantation

γδ T cells are a subpopulation of lymphocytes expressing heterodimeric T-cell receptors composed of γ and δ chains. They are morphologically and functionally heterogeneous, innate yet also adaptive in behavior, and exhibit diverse activities spanning immunosurveillance, immunomodulation, and direct cytotoxicity. The specific responses of γδ T cells to allografts are yet to be fully elucidated with evidence of both detrimental and tolerogenic roles in different settings. Here we present an overview of γδ T-cell literature, consider ways in which their functional heterogeneity contributes to the outcomes after transplantation, and reflect on methods to harness their beneficial properties.

Increased frequency of systemic pro-inflammatory Vδ1+ γδ T cells in HIV elite controllers correlates with gut viral load

γδ T cells predominate in the intestinal mucosa and help maintain gut homeostasis and mucosal immunity. Although HIV infection significantly alters these cells, what drives these perturbations is unclear. Growing evidence suggests that impaired intestinal immune function in HIV leads to chronic immune activation and disease progression. This occurs even in HIV controllers - individuals with undetectable HIV viremia without antiretroviral therapy (ART). We show that Vδ1⁺ cells, a subset of γδ T cells described as being important in intestinal barrier function, increase in frequency in HIV-infected individuals, including HIV controllers. These cells resemble terminally differentiated effector memory cells, producing the pro-inflammatory cytokines IFNγ, TNFα, and MIP-1β upon stimulation. Importantly, pro-inflammatory Vδ1⁺ cell frequency correlates with levels of HIV RNA in intestinal tissue but not in plasma. This study supports a model in which local viral replication in the gut in HIV controllers disrupts the phenotype and function of Vδ1⁺ cells, a cell type involved in the maintenance of epithelial barrier integrity, and may thereby contribute to systemic immune activation and HIV disease progression.

Improving CLL Vγ9Vδ2-T-cell fitness for cellular therapy by ex vivo activation and ibrutinib

The efficacy of autologous (αβ) T-cell-based treatment strategies in chronic lymphocytic leukemia (CLL) has been modest. The Vγ9Vδ2-T cell subset consists of cytotoxic T lymphocytes with potent antilymphoma activity via a major histocompatibility complex-independent mechanism. We studied whether Vγ9Vδ2-T cells can be exploited as autologous effector lymphocytes in CLL. Healthy control Vγ9Vδ2-T cells were activated by and had potent cytolytic activity against CLL cells. However, CLL-derived Vγ9Vδ2-T cells proved dysfunctional with respect to effector cytokine production and degranulation, despite an increased frequency of the effector-type subset. Consequently, cytotoxicity against malignant B cells was hampered. A comparable dysfunctional phenotype was observed in healthy Vγ9Vδ2-T cells after coculture with CLL cells, indicating a leukemia-induced mechanism. Gene-expression profiling implicated alterations in synapse formation as a conceivable contributor to compromised Vγ9Vδ2-T-cell function in CLL patients. Dysfunction of Vγ9Vδ2-T cells was fully reversible upon activation with autologous monocyte-derived dendritic cells (moDCs). moDC activation resulted in efficient expansion and predominantly yielded Vγ9Vδ2-T cells with a memory phenotype. Furthermore, ibrutinib treatment promoted an antitumor T helper 1 (T_H1) phenotype in Vγ9Vδ2-T cells, and we demonstrated binding of ibrutinib to IL-2-inducible kinase (ITK) in Vγ9Vδ2-T cells. Taken together, CLL-mediated dysfunction of autologous Vγ9Vδ2-T cells is fully reversible, resulting in potent cytotoxicity toward CLL cells. Our data support the potential use of Vγ9Vδ2-T cells as effector T cells in CLL immunotherapy and favor further exploration of combining Vγ9Vδ2-T-cell-based therapy with ibrutinib.

Protective Role of γδ T Cells in Different Pathogen Infections and Its Potential Clinical Application

γδ T cells, a subgroup of T cells based on the γδ TCR, when compared with conventional T cells (αβ T cells), make up a very small proportion of T cells. However, its various subgroups are widely distributed in different parts of the human body and are attractive effectors for infectious disease immunity. γδ T cells are activated and expanded by nonpeptidic antigens (P-Ags), major histocompatibility complex (MHC) molecules, and lipids which are associated with different kinds of pathogen infections. Activation and proliferation of γδ T cells play a significant role in diverse infectious diseases induced by viruses, bacteria, and parasites and exert their potential effector function to effectively eliminate infection. It is well known that many types of infectious diseases are detrimental to human life and health and give rise to high incidence of illnesses and death rate all over the world. To date, there is no comprehensive understanding of the correlation between γδ T cells and infectious diseases. In this review, we will focus on the various subgroups of γδ T cells (mainly Vδ1 T cells and Vδ2 T cells) which can induce multiple immune responses or effective functions to fight against common pathogen infections, such as Mycobacterium tuberculosis, Listeria monocytogenes, influenza viruses, HIV, EBV, and HBV. Hopefully, the gamma-delta T cell study will provide a novel effective way to treat infectious diseases.

Immune Regulation of Skin Wound Healing: Mechanisms and Novel Therapeutic Targets

Significance: The immune system plays a central role in orchestrating the tissue healing process. Hence, controlling the immune system to promote tissue repair and regeneration is an attractive approach when designing regenerative strategies. This review discusses the pathophysiology of both acute and chronic wounds and possible strategies to control the immune system to accelerate chronic wound closure and promote skin regeneration (scar-less healing) of acute wounds. Recent Advances: Recent studies have revealed the key roles of various immune cells and immune mediators in skin repair. Thus, immune components have been targeted to promote chronic wound repair or skin regeneration and several growth factors, cytokines, and biomaterials have shown promising results in animal models. However, these novel strategies are often struggling to meet efficacy standards in clinical trials, partly due to inadequate drug delivery systems and safety concerns. Critical Issues: Excess inflammation is a major culprit in the dysregulation of normal wound healing, and further limiting inflammation effectively reduces scarring. However, current knowledge is insufficient to efficiently control inflammation and specific immune cells. This is further complicated by inadequate drug delivery methods. Future Directions: Improving our understanding of the molecular pathways through which the immune system controls the wound healing process could facilitate the design of novel regenerative therapies. Additionally, better delivery systems may make current and future therapies more effective. To promote the entry of current regenerative strategies into clinical trials, more evidence on their safety, efficacy, and cost-effectiveness is also needed.

Lymph node γδ and αβ CD8+ T cells share migratory properties

During immune responses, T cells differentiate into subsets with different functions and migratory properties. Here we characterize migratory behavior of endogenous αβ CD8+ and γδ T cells in lymph nodes by long-term tracking following in vivo photoconversion. We identified subsets of γδ T cells with distinct circulation kinetics that closely mirrored migratory subsets of αβ CD8+ T cells. Notably, αβ CD8+ and γδ T cells both comprised resident populations which stayed in lymph nodes for 4 weeks without circulation or proliferation. Furthermore, in contrast to the common conception, we observed that central memory αβ CD8+ T cells circulate with slower kinetics than naïve cells. Our results show that, similar to αβ T cells, γδ T cells can acquire distinct migratory properties during their development and differentiation and reveal unexpected intricacies of T cell migratory patterns.

Functions of Vγ4 T Cells and Dendritic Epidermal T Cells on Skin Wound Healing

Wound healing is a complex and dynamic process that progresses through the distinct phases of hemostasis, inflammation, proliferation, and remodeling. Both inflammation and re-epithelialization, in which skin γδ T cells are heavily involved, are required for efficient skin wound healing. Dendritic epidermal T cells (DETCs), which reside in murine epidermis, are activated to secrete epidermal cell growth factors, such as IGF-1 and KGF-1/2, to promote re-epithelialization after skin injury. Epidermal IL-15 is not only required for DETC homeostasis in the intact epidermis but it also facilitates the activation and IGF-1 production of DETC after skin injury. Further, the epidermal expression of IL-15 and IGF-1 constitutes a feedback regulatory loop to promote wound repair. Dermis-resident Vγ4 T cells infiltrate into the epidermis at the wound edges through the CCR6-CCL20 pathway after skin injury and provide a major source of IL-17A, which enhances the production of IL-1β and IL-23 in the epidermis to form a positive feedback loop for the initiation and amplification of local inflammation at the early stages of wound healing. IL-1β and IL-23 suppress the production of IGF-1 by DETCs and, therefore, impede wound healing. A functional loop may exist among Vγ4 T cells, epidermal cells, and DETCs to regulate wound repair.

Origin and Evolution of Dendritic Epidermal T Cells

Dendritic epidermal T cells (DETCs) expressing invariant Vγ5Vδ1 T-cell receptors (TCRs) play a crucial role in maintaining skin homeostasis in mice. When activated, they secrete cytokines, which recruit various immune cells to sites of infection and promote wound healing. Recently, a member of the butyrophilin family, Skint1, expressed specifically in the skin and thymus was identified as a gene required for DETC development in mice. Skint1 is a gene that arose by rodent-specific gene duplication. Consequently, a gene orthologs to mouse Skint1 exists only in rodents, indicating that Skint1-dependent DETCs are unique to rodents. However, dendritic-shaped epidermal γδ T cells with limited antigen receptor diversity appear to occur in other mammals. Even lampreys, a member of the most primitive class of vertebrates that even lacks TCRs, have γδ T-like lymphocytes that resemble DETCs. This indicates that species as divergent as mice and lampreys share the needs to have innate-like T cells at their body surface, and that the origin of DETC-like cells is as ancient as that of lymphocytes.

Histological and immunological characteristics of the junctional epithelium

The continuity of epithelial tissue is collapsed by tooth eruption. The junctional epithelium (JE) is attached to the tooth surface by hemidesmosomes, which constitutes the front-line defense against periodontal bacterial infection. JE constitutively expresses intercellular adhesion molecule-1 (ICAM-1), and neutrophils and lymphocytes penetrate into JE via interaction between ICAM-1 and LFA-1 expressed on the surface of these migrating cells. JE also expresses cytokines and chemokines. These functions of JE are maintained even in germ-free condition. Therefore, the constitutive expression of adhesion molecules, cytokines, and chemokines might be used not only for anti-pathogenic defense but also for maintaining the physiological homeostasis of JE. In this review, we have mainly focused on the structural and functional features of JE, and discussed the function of intraepithelial lymphocytes in JE as a front-line anti-microbial defense barrier and regulator of JE hemostasis.

The NKG2D/NKG2DL Axis in the Crosstalk Between Lymphoid and Myeloid Cells in Health and Disease

Natural killer group 2, member D (NKG2D) receptor is a type II transmembrane protein expressed by both innate and adaptive immune cells, including natural killer (NK) cells, CD8+ T cells, invariant NKT cells, γδ T cells, and some CD4+ T cells under certain pathological conditions. NKG2D is an activating NK receptor that induces cytotoxicity and production of cytokines by effector cells and supports their proliferation and survival upon engagement with its ligands. In both innate and T cell populations, NKG2D can costimulate responses induced by other receptors, such as TCR in T cells or NKp46 in NK cells. NKG2D ligands (NKG2DLs) are remarkably diverse. Initially, NKG2DL expression was typically attributed to stressed, infected, or transformed cells, thus signaling “dysregulated-self.” However, many reports indicated their expression under homeostatic conditions, usually in the context of cell activation and/or proliferation. Myeloid cells, including macrophages and dendritic cells (DCs), are among the first cells sensing and responding to pathogens and tissue damage. By secreting a plethora of soluble mediators, by presenting antigens to T cells and by expressing costimulatory molecules, myeloid cells play vital roles in inducing and supporting responses of other immune cells in lymphoid organs and tissues. When activated, both macrophages and DCs upregulate NKG2DLs, thereby enabling them with additional mechanisms for regulating lymphocyte responses. In this review, we will focus on the expression of NKG2D by innate and adaptive lymphocytes, the regulation of NKG2DL expression on myeloid cells, and the contribution of the NKG2D/NKG2DL axis to the crosstalk of myeloid cells with NKG2D-expressing lymphocytes. In addition, we will highlight pathophysiological conditions associated with NKG2D/NKG2DL dysregulation and discuss the putative involvement of the NKG2D/NKG2DL axis in the lymphocyte/myeloid cell crosstalk in these diseases.

Strong TCRγδ Signaling Prohibits Thymic Development of IL-17A-Secreting γδ T Cells

Despite a growing appreciation of γδ T cell contributions to numerous immune responses, the mechanisms that underpin their thymic development remain poorly understood. Here, using precursor/product relationships, we identify thymic stages in two distinct developmental pathways that generate γδ T cells pre-committed to subsequent secretion of either IL-17A or IFNγ. Importantly, this framework for tracking γδ T cell development has permitted definitive assessment of TCRγδ signal strength in commitment to γδ T cell effector fate; increased TCRγδ signal strength profoundly prohibited the development of all IL-17A-secreting γδ T cells, regardless of Vγ usage, but promoted the development of γδ progenitors along the IFNγ pathway. This clarifies the recently debated role of TCRγδ signal strength in commitment to distinct γδ T cell effector fates and proposes an alternate methodology for the study of γδ T cell development.

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CD44 and CD45RB identify two distinct thymic γδ T cell developmental pathways

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Cytokine-secretion-independent identification of effector fate-committed γδ T cells

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Sizable numbers of IL-17A-committed γδ T cells express Vγ1 and Vγ2/3 chains

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Increased TCRγδ signal strength prohibits development of IL-17A-secreting γδ T cells

Vγ4 T Cells Inhibit the Pro-healing Functions of Dendritic Epidermal T Cells to Delay Skin Wound Closure Through IL-17A

Dendritic epidermal T cells (DETCs) and dermal Vγ4 T cells engage in wound re-epithelialization and skin inflammation. However, it remains unknown whether a functional link between Vγ4 T cell pro-inflammation and DETC pro-healing exists to affect the outcome of skin wound closure. Here, we revealed that Vγ4 T cell-derived IL-17A inhibited IGF-1 production by DETCs to delay skin wound healing. Epidermal IL-1β and IL-23 were required for Vγ4 T cells to suppress IGF-1 production by DETCs after skin injury. Moreover, we clarified that IL-1β rather than IL-23 played a more important role in inhibiting IGF-1 production by DETCs in an NF-κB-dependent manner. Together, these findings suggested a mechanistic link between Vγ4 T cell-derived IL-17A, epidermal IL-1β/IL-23, DETC-derived IGF-1, and wound-healing responses in the skin.

γδ T cell-mediated individualized immunotherapy for hepatocellular carcinoma considering clinicopathological characteristics and immunosuppressive factors

Hepatocellular carcinoma (HCC) is the most common form of primary liver cancer. γδ T cells have been revealed to be promising candidates for immunotherapy in patients with HCC. However, the use of these cells in clinical practice has been demonstrated to be challenging. In the present study, γδ T cells isolated from the peripheral blood of patients with HCC (n=83) and healthy donors (n=15) were characterized. Flow cytometry was used to analyze the proportion, phenotype, tumor-killing capacity and cytokine secretion of regulatory T cells (Tregs) and γδ T17 cells in peripheral blood samples prior to and following amplification. Interleukin (IL)-17A levels in the supernatant was analyzed using an ELISA on days 3, 7, 10 and 14. The in vitro cytotoxicity of γδ T cells was measured using an MTT assay. It was revealed that zoledronate with IL-2 may efficiently expand γδ T cells sourced from the peripheral blood of patients with HCC. The amplification capacity of γδ T cells was associated with the clinicopathological characteristics of patients (clinical stage, levels of AFP and albumin, duration of disease, size and number of tumors, numbers of Tregs and γδ T17 cells, and levels of IL-17A). The proportion of γδ T cells positive for interferon-γ, tumor necrosis factor-α, granzyme B, perforin, and lysosome-associated membrane protein 1 was almost unchanged prior to and following amplification. Following amplification, the in vitro cytotoxicity of γδ T cells also remained unchanged. γδ T17 cells, Tregs and IL-17A levels were not altered during amplification. In summary, following in vitro amplification, circulating γδ T cells were revealed to possess features that may make them suitable for immunotherapy for HCC without increasing immunosuppressive factors. However, immunotherapy should be individualized according to the clinicopathological features of patients.

Leptospirosis: Molecular trial path and immunopathogenesis correlated with dengue, malaria and mimetic hemorrhagic infections

Immuno-pathogenesis of leptospirosis can be recounted well by following its trail path from entry to exit, while inducing disastrous damages in various tissues of the host. Dysregulated, inappropriate and excessive immune responses are unanimously blamed in fatal leptospirosis. The inherent abilities of the pathogen and inabilities of the host were debated targeting the severity of the disease. Hemorrhagic manifestation through various mechanisms leading to a fatal end is observed when this disease is unattended. The similar vascular destructions and hemorrhage manifestations are noted in infections with different microbes in endemic areas. The simultaneous infection in a host with more than one pathogen or parasite is referred as the coinfection. Notably, common endemic infections such as leptospirosis, dengue, chikungunya, and malaria, harbor favorable environments to flourish in similar climates, which is aggregated with stagnated water and aggravated with the poor personal and environmental hygiene of the inhabitants. These factors aid the spread of pathogens and parasites to humans and potential vectors, eventually leading to outbreaks of public health relevance. Malaria, dengue and chikungunya need mosquitoes as vectors, in contrast with leptospirosis, which directly invades human, although the environmental bacterial load is maintained through other mammals, such as rodents. The more complicating issue is that infections by different pathogens exhibiting similar symptoms but require different treatment management. The current review explores different pathogens expressing specific surface proteins and their ability to bind with array of host proteins with or without immune response to enter into the host tissues and their ability to evade the host immune responses to invade and their affinity to certain tissues leading to the common squeal of hemorrhage. Furthermore, at the host level, the increased susceptibility and inability of the host to arrest the pathogens' and parasites' spread in different tissues, various cytokines accumulated to eradicate the microorganisms and their cellular interactions, the antibody dependent defense and the susceptibility of individual organs bringing the manifestation of the diseases were explored. Lastly, we provided a discussion on the immune trail path of pathogenesis from entry to exit to narrate the similarities and dissimilarities among various hemorrhagic fevers mentioned above, in order to outline future possibilities of prevention, diagnosis, and treatment of coinfections, with special reference to endemic areas.

A Retrospective Analysis of γδ T Cell Expression in Chronic Rhinosinusitis and Its Association with Recurrence of Nasal Polyps

BACKGROUND/AIMS

To examine whether γδ T cell is expressed in the nasal mucosa of chronic rhinosinusitis (CRS) patients and its potential association with recurrence of nasal polyps.

METHODS

Thirty-six patients with CRS with nasal polyps (CRSwNP) and 25 patients with CRS without nasal polyps (CRSsNP) were recruited. Twenty-six patients with other nasal diseases served as controls. The CRSwNP group was divided into the eosinophilic CRSwNP and noneosinophilic CRSwNP groups. The expression of γδ T cells was detected by immunohistochemistry. The expression of each subtype of γδ T cells was detected by using qRT-PCR. All patients underwent nasal endoscopy, and postoperative follow-up lasted over 12 months. CRS patients were evaluated by preoperative VAS scores of symptoms and nasal endoscopy Lund-Kennedy scores.

RESULTS

The expression of γδ T cells in the CRSwNP groups was stronger than in the CRSsNP and the control group (p < 0.05, p < 0.05). The expression of Vγ1+γδ T cells in the eosinophilic CRSwNP group was higher than that in the CRSsNP group and the control group (p < 0.05, p < 0.05). The expression of γδ T cells was associated with high rate of recurrence, tissue eosinophil infiltration, worse symptom score of nasal obstruction, and higher Lund-Kennedy score (all p < 0.05).

CONCLUSIONS

Increased expression of γδ T cells in CRSwNP may be associated with recurrence of nasal polyps.

γδ T Cells: Unexpected Regulators of Cancer Development and Progression

Accumulating evidence suggests a role for gamma delta (γδ) T cells as unexpected drivers of tumor development and progression. These protumoral γδ T cells are abundant in the tumor microenvironment in both mouse and human. They promote tumor progression by: (i) inducing an immunosuppressive tumor microenvironment and angiogenesis via cytokine production; (ii) functioning as regulatory T (Treg)/T helper 2 (Th2)-like cells; (iii) interfering with dendritic cell (DC) effector function; and (iv) inhibiting antitumor adaptive T cell immunity via the programmed death-1 (PD-1)-programmed death ligand-1 (PD-L1) pathway. Understanding how these cells are regulated and what their specific role in cancer is will provide insight for the development of approaches that specifically target these cells and can thereby improve the efficacy of cancer immunotherapies.