Membrane HSP70: the molecule triggering gammadelta T cells in the early stage of tumorigenesis

GRP78 Downregulation in Keratinocytes Promotes Skin Inflammation through the Recruitment and Activation of CCR6+ IL-17A-Producing γδ T Cells

The migration of γδ T lymphocytes toward skin lesions and their concomitant pathogenic IL-17A production play a crucial role in the pathogenesis of psoriasis. However, the regulatory mechanisms of IL-17A production by γδ T cells and their migration remain to be fully explored. Intracellular GRP78 is a molecular chaperone that regulates endoplasmic reticulum stress, whereas secretory GRP78, as a member of the resolution-associated molecular patterns, exerts immunoregulatory effects. In this study, we reported that both the intracellular GRP78 in skin lesions and secretory GRP78 in the serum were significantly decreased in patients with psoriasis. A GRP78 knockdown exacerbated imiquimod-induced skin inflammation, whereas the application of recombinant GRP78 protein or BIP inducer X (a GRP78 inducer) attenuated the dermatitis. Mechanistically, the GRP78 knockdown in keratinocytes enhanced the production of chemokines, specifically CCL20, which regulates γδ T-cell migration. Moreover, recombinant GRP78 was found to directly bind to γδ T cells to suppress its migration ability and proinflammatory capacities by downregulating the CCR6 and IL-17A expression. Collectively, our results uncovered a pivotal role of GRP78 in the pathogenesis of psoriasis, which was mainly exerted by regulating the interaction between keratinocytes and γδ T cells, and might provide a promising target for psoriasis therapy.

Clinically relevant immune subtypes based on alternative splicing landscape of immune-related genes for lung cancer advanced PPPM approach

Background

Alternative splicing (AS) occurs in the process of gene post-transcriptional process, which is very important for the correct synthesis and function of protein. The change of AS pattern may lead to the change of expression level or function of lung cancer-related genes, and then affect the occurrence and development of lung cancers. The specific AS pattern might be used as a biomarker for early warning and prognostic assessment of a cancer in the framework of predictive, preventive, and personalized medicine (PPPM; 3PM). AS events of immune-related genes (IRGs) were closely associated with tumor progression and immunotherapy. We hypothesize that IRG-AS events are significantly different in lung adenocarcinomas (LUADs) vs. controls or in lung squamous cell carcinomas (LUSCs) vs. controls. IRG-AS alteration profiling was identified to construct IRG-differentially expressed AS (IRG-DEAS) signature models. Study on the selective AS events of specific IRGs in lung cancer patients might be of great significance for further exploring the pathogenesis of lung cancer, realizing early detection and effective monitoring of lung cancer, finding new therapeutic targets, overcoming drug resistance, and developing more effective therapeutic strategies, and better used for the prediction, diagnosis, prevention, and personalized medicine of lung cancer.

Methods

The transcriptomic, clinical, and AS data of LUADs and LUSCs were downloaded from TCGA and its SpliceSeq databases. IRG-DEAS events were identified in LUAD and LUSC, followed by their functional characteristics, and overall survival (OS) analyses. OS-related IRG-DEAS prognostic models were constructed for LUAD and LUSC with Lasso regression, which were used to classify LUADs and LUSCs into low- and high-risk score groups. Furthermore, the immune cell distribution, immune-related scores, drug sensitivity, mutation status, and GSEA/GSVA status were analyzed between low- and high-risk score groups. Also, low- and high-immunity clusters and AS factor (SF)-OS-related-AS co-expression network and verification of cell function of CELF6 were analyzed in LUAD and LUSC.

Results

Comprehensive analysis of transcriptomic, clinical, and AS data of LUADs and LUSCs identified IRG-AS events in LUAD (n = 1607) and LUSC (n = 1656), including OS-related IRG-AS events in LUAD (n = 127) and LUSC (n = 105). A total of 66 IRG-DEAS events in LUAD and 89 IRG-DEAS events in LUSC were identified compared to controls. The overlapping analysis between IRG-DEASs and OS-related IRG-AS events revealed 14 OS-related IRG-DEAS events for LUAD and 16 OS-related IRG-DEAS events for LUSC, which were used to identify and optimize a 12-OS-related-IRG-DEAS signature prognostic model for LUAD and an 11-OS-related-IRG-DEAS signature prognostic model for LUSC. These two prognostic models effectively divided LUAD or LUSC samples into low- and high-risk score groups that were closely associated with OS, clinical characteristics, and tumor immune microenvironment, with significant gene sets and pathways enriched in the two groups. Moreover, weighted gene co-expression network (WGCNA) and nonnegative matrix factorization method (NMF) analyses identified four OS-relevant subtypes of LUAD and six OS-relevant subtypes of LUSC, and ssGSEA identified five immunity-relevant subtypes of LUAD and five immunity-relevant subtypes of LUSC. Interestingly, splicing factors-OS-related-AS network revealed hub molecule CELF6 was significantly related to the malignant phenotype in lung cancer cells.

Conclusions

This study established two reliable IRG-DEAS signature prognostic models and constructed interesting splicing factor-splicing event networks in LUAD and LUSC, which can be used to construct clinically relevant immune subtypes, patient stratification, prognostic prediction, and personalized medical services in the PPPM practice.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-024-00366-4.

IL-22 Binding Protein Controls IL-22-Driven Bleomycin-Induced Lung Injury

The high mortality rates of acute lung injury and acute respiratory distress syndrome challenge the field to identify biomarkers and factors that can be exploited for therapeutic approaches. IL-22 is a cytokine that has antibacterial and reparative properties in the lung. However, it also can exacerbate inflammation and requires tight control by the extracellular inhibitory protein known as IL-22 binding protein (IL-22BP) (Il22ra2). This study showed the necessity of IL-22BP in controlling and preventing acute lung injury using IL-22BP knockout mice (Il22ra2-/-) in the bleomycin model of acute lung injury/acute respiratory distress syndrome. Il22ra2-/- mice had greater sensitivity (weight loss and death) and pulmonary inflammation in the acute phase (first 7 days) of the injury compared with wild-type C57Bl/6 controls. The inflammation was driven by excess IL-22 production, inducing the influx of pathogenic IL-17A+ γδ T cells to the lung. Interestingly, this inflammation was initiated in part by the noncanonical IL-22 signaling to macrophages, which express the IL-22 receptor (Il22ra1) in vivo after bleomycin challenge. This study further showed that IL-22 receptor alpha-1+ macrophages can be stimulated by IL-22 to produce a number of IL-17-inducing cytokines such as IL-1β, IL-6, and transforming growth factor-β1. Together, the results suggest that IL-22BP prevents IL-22 signaling to macrophages and reduces bleomycin-mediated lung injury.

Enhancing the effectiveness of γδ T cells by mRNA transfection of chimeric antigen receptors or bispecific T cell engagers

Adoptive cell therapy (ACT) utilizing γδ T cells is becoming a promising option for the treatment of cancer, because it offers an off-the-shelf allogeneic product that is safe, potent, and clinically effective. Approaches to engineer or enhance immune-competent cells for ACT, like expression of chimeric antigen receptors (CARs) or combination treatments with bispecific T cell engagers, have improved the specificity and cytotoxic potential of ACTs and have shown great promise in preclinical and clinical settings. Here, we test whether electroporation of γδ T cells with CAR or secreted bispecific T cell engager (sBite) mRNA is an effective approach to improve the cytotoxicity of γδ T cells. Using a CD19-specific CAR, approximately 60% of γδ T cells are modified after mRNA electroporation and these cells show potent anticancer activity in vitro and in vivo against two CD19-positive cancer cell lines. In addition, expression and secretion of a CD19 sBite enhances γδ T cell cytotoxicity, both in vitro and in vivo, and promotes killing of target cells by modified and unmodified γδ T cells. Taken together, we show that transient transfection of γδ T cells with CAR or sBite mRNA by electroporation can be an effective treatment platform as a cancer therapeutic.

Controversial role of γδ T cells in pancreatic cancer

γδ T cells are rare lymphocytes with cogent impact on immune responses. These cells are one of the earliest cells to be recruited in the sites of infection or tumors and play a critical role in coordinating innate and adaptive immune responses. The anti-tumor activity of γδ T cells have been numerously reported; nonetheless, there is controversy among published studies regarding their anti-tumor vs pro-tumor effect- especially in pancreatic cancer. A myriad of studies has confirmed that activated γδ T cells can potently lyse a broad variety of solid tumors and leukemia/lymphoma cells and produce an array of cytokines; however, early γδ T cell-based clinical trials did not lead to optimal efficacy, despite acceptable safety. Depending on the local micromilieu, γδ T cells can differentiate into tumor promoting or suppressing cells such as Th1-, Th2-, or Th17-like cells and produce prototypical cytokines such as interferon-γ (IFNγ) and interleukin (IL)-4/-10, IL-9, or IL-17. In an abstruse tumor such as pancreatic cancer- also known as immunologically cold tumor- γδ T cells are more likely to switch to their immunosuppressive phenotype. In this review we will adduce the accumulated knowledge on these two controversial aspects of γδ T cells in cancers- with a focus on solid tumors and pancreatic cancer. In addition, we propose strategies for enhancing the anti-tumor function of γδ T cells in cancers and discuss the potential future directions.

γδ T cell costimulatory ligands in antitumor immunity

Antitumor immunity relies on the ability of T cells to recognize and kill tumor targets. γδ T cells are a specialized subset of T cells that predominantly localizes to non-lymphoid tissue such as the skin, gut, and lung where they are actively involved in tumor immunosurveillance. γδ T cells respond to self-stress ligands that are increased on many tumor cells, and these interactions provide costimulatory signals that promote their activation and cytotoxicity. This review will cover costimulatory molecules that are known to be critical for the function of γδ T cells with a specific focus on mouse dendritic epidermal T cells (DETC). DETC are a prototypic tissue-resident γδ T cell population with known roles in antitumor immunity and are therefore useful for identifying mechanisms that may control activation of other γδ T cell subsets within non-lymphoid tissues. This review concludes with a brief discussion on how γδ T cell costimulatory molecules can be targeted for improved cancer immunotherapy.

The Role of Extracellular HSP70 in the Function of Tumor-Associated Immune Cells

Simple Summary

The intracellular heat shock protein 70 (HSP70) is essential for cells to respond to stress, for instance, by refolding damaged proteins or inhibiting apoptosis. However, in cancer, HSP70 is overexpressed and can translocate to the extracellular milieu, where it emerged as an important modulator of tumor-associated immune cells. By targeting the tumor microenvironment (TME) through different mechanisms, extracellular HSP70 can trigger pro- or anti-tumorigenic responses. Therefore, understanding the pathways and their consequences is crucial for therapeutically targeting cancer and its surrounding microenvironment. In this review, we summarize current knowledge on the translocation of extracellular HSP70. We further elucidate its functions within the TME and provide an overview of potential therapeutic options.

Abstract

Extracellular vesicles released by tumor cells (T-EVs) are known to contain danger-associated molecular patterns (DAMPs), which are released in response to cellular stress to alert the immune system to the dangerous cell. Part of this defense mechanism is the heat shock protein 70 (HSP70), and HSP70-positive T-EVs are known to trigger anti-tumor immune responses. Moreover, extracellular HSP70 acts as an immunogen that contributes to the cross-presentation of major histocompatibility complex (MHC) class I molecules. However, the release of DAMPs, including HSP70, may also induce chronic inflammation or suppress immune cell activity, promoting tumor growth. Here, we summarize the current knowledge on soluble, membrane-bound, and EV-associated HSP70 regarding their functions in regulating tumor-associated immune cells in the tumor microenvironment. The molecular mechanisms involved in the translocation of HSP70 to the plasma membrane of tumor cells and its release via exosomes or soluble proteins are summarized. Furthermore, perspectives for immunotherapies aimed to target HSP70 and its receptors for cancer treatment are discussed and presented.

Association between Serum Heat Shock Proteins and Gamma-Delta T Cells—An Outdated Clue or a New Direction in Searching for an Anticancer Strategy? A Short Report

HSPs demonstrate a strong association with gamma-delta (γδ) T cells. Most of the studies regarding interactions between the parameters were conducted in the 1990s. Despite promising results, the concept of targeting γδ T cells by HSPs seems to be a forgotten direction due to potent non-peptidic phosphoantigens rather than HSPs have been found to be the essential stimulatory components for human γδ cells. Currently, with greater knowledge of lymphocyte diversity, and more accurate diagnostic methods, we decided to study the correlation once again in the neoplastic condition. Twenty-one children with newly diagnosed acute lymphoblastic leukaemia (ALL) were enrolled on the study. Serum HSP90 concentrations were evaluated by an enzyme-linked immunosorbent assay (ELISA), subsets of γδ T cells (CD3+ γδ, CD3+ γδ HLA/DR+, CD4+ γδ and CD8+ γδ) by flow cytometry. We have shown statistically relevant correlations between serum HSP90 and CD3+ HLA/DR+ γδ T cells in paediatric ALL at diagnosis (R = 0.53, p < 0.05), but not after induction chemotherapy. We also have demonstrated decreased levels of both serum HSP90 and CD3+ HLA/DR+ γδ T cells before treatment, which may indirectly indicate dose-dependent unknown interaction between the parameters. The results of our study may be a good introduction to research on the association between HSPs and CD3+ HLA/DR+ γδ T cells, which could be an interesting direction for the development of anti-cancer strategies, not just for childhood ALL.

The Dual Roles of Human γδ T Cells: Anti-Tumor or Tumor-Promoting

γδ T cells are the unique T cell subgroup with their T cell receptors composed of γ chain and δ chain. Unlike αβ T cells, γδ T cells are non-MHC-restricted in recognizing tumor antigens, and therefore defined as innate immune cells. Activated γδ T cells can promote the anti-tumor function of adaptive immune cells. They are considered as a bridge between adaptive immunity and innate immunity. However, several other studies have shown that γδ T cells can also promote tumor progression by inhibiting anti-tumor response. Therefore, γδ T cells may have both anti-tumor and tumor-promoting effects. In order to clarify this contradiction, in this review, we summarized the functions of the main subsets of human γδ T cells in how they exhibit their respective anti-tumor or pro-tumor effects in cancer. Then, we reviewed recent γδ T cell-based anti-tumor immunotherapy. Finally, we summarized the existing problems and prospect of this immunotherapy.

EBV transformation induces overexpression of hMSH2/3/6 on B lymphocytes and enhances γδT-cell-mediated cytotoxicity via TCR and NKG2D

The engagement of Epstein-Barr virus (EBV)-induced protein ligands in γδ T-cell-mediated anti-EBV immunity, especially in EBV-associated B-cell malignancies, has not been fully elucidated. Previously we reported the overexpression of human MutS homologue 2 (hMSH2), a stress-inducible protein ligand for human γδ T-cells, on EBV-transformed B lymphoblastic cell lines (B-LCLs). In this study, we first generated EBV-transformed B-LCLs from peripheral blood mononuclear cells of healthy volunteers with B95-8 cellular supernatant and cyclosporine A. Secondly, we demonstrated the significantly elevated cell surface protein expression and mRNA transcription of hMSH2 in EBV-transformed B-LCLs, 3D5 and EBV-positive B lymphoma cell line Daudi and Raji. Thirdly, hMSH2-mediated recognition of EBV-transformed B malignant cells by human γδ T-cells was confirmed by specific antibody blocking and siRNA interference. Both TCRγδ and NKG2D participated in hMSH2-mediated recognition of EBV-transformed B malignant cells. Furthermore, hMSH3 and hMSH6, the companion proteins of hMSH2, along with CD98, were found overexpressed on the surface of EBV-transformed malignant B-cells. We concluded that the induced overexpression of hMSH proteins might serve as early alerting biomarkers emerged in EBV-related B-cell malignances or as potential targets for establishing γδ T-cell-based therapeutic immunotherapies towards EBV infection.

Heat Shock Proteins and Cancer

Heat shock proteins (HSPs) constitute a large family of proteins involved in protein folding and maturation whose expression is induced by heat shock or other stressors. The major groups are classified based on their molecular weights and include HSP27, HSP40, HSP60, HSP70, HSP90, and large HSPs. HSPs play a significant role in cellular proliferation, differentiation, and carcinogenesis. In this article we comprehensively review the roles of major HSPs in cancer biology and pharmacology. HSPs are thought to play significant roles in the molecular mechanisms leading to cancer development and metastasis. HSPs may also have potential clinical uses as biomarkers for cancer diagnosis, for assessing disease progression, or as therapeutic targets for cancer therapy.

Chaperonin-containing T-complex Protein 1 Subunit ζ Serves as an Autoantigen Recognized by Human Vδ2 γδ T Cells in Autoimmune Diseases

Human γδ T cells recognize conserved endogenous and stress-induced antigens typically associated with autoimmune diseases. However, the role of γδ T cells in autoimmune diseases is not clear. Few autoimmune disease-related antigens recognized by T cell receptor (TCR) γδ have been defined. In this study, we compared Vδ2 TCR complementarity-determining region 3 (CDR3) between systemic lupus erythematosus (SLE) patients and healthy donors. Results show that CDR3 length distribution differed significantly and displayed oligoclonal characteristics in SLE patients when compared with healthy donors. We found no difference in the frequency of Jδ gene fragment usage between these two groups. According to the dominant CDR3δ sequences in SLE patients, synthesized SL2 peptides specifically bound to human renal proximal tubular epithelial cell line HK-2; SL2-Vm, a mutant V sequence of SL2, did not bind. We identified the putative protein ligand chaperonin-containing T-complex protein 1 subunit ζ (CCT6A) using SL2 as a probe in HK-2 cell protein extracts by affinity chromatography and liquid chromatography-electrospray ionization-tandem mass spectrometry analysis. We found CCT6A expression on the surface of HK-2 cells. Cytotoxicity of only Vδ2 γδ T cells to HK-2 cells was blocked by anti-CCT6A antibody. Finally, we note that CCT6A concentration was significantly increased in plasma of SLE and rheumatoid arthritis patients. These data suggest that CCT6A is a novel autoantigen recognized by Vδ2 γδ T cells, which deepens our understanding of mechanisms in autoimmune diseases.

The limited capacity of malignant glioma-derived exosomes to suppress peripheral immune effectors

Tumor-derived microvesicular exosomes permit intercellular communication both locally and systemically by delivering a snapshot of the tumor cell's constituents. We thus investigated whether exosomes mediate malignant glioma's facility for inducing peripheral immunosuppression. In Western blot and RT-PCR analyses, glioma-derived exosomes displayed exosome-specific markers, but failed to recapitulate the antigen-presentation machinery, surface co-modulatory signals, or immunosuppressive mediator status of their parent tumor cells. Treatment with glioma-derived exosomes promoted immunosuppressive HLA-DR(low) monocytic phenotypes, but failed to induce monocytic PD-L1 expression or alter the activation of cytotoxic T-cells from patients' peripheral blood by FACS and RT-PCR analyses. Our results suggest that malignant glioma-derived exosomes are restricted in their capacity to directly prime peripheral immunosuppression.

Characterization of complementary determinant region 3δ in human MutS homologue 2-specific γδ T cells

γδT cells function as sentinels in early host responses to infections and malignancies. Previously, we found ectopically expressed human MutS homologue 2 (hMSH2), recognized by γδT cells, triggered a γδT cell-mediated cytolysis to tumor cells. However, the characteristics of hMSH2-specific γδ Τ cells are not fully understood. In this study, we investigated the complementary determinant region (CDR) 3δ diversity of hMSH2-specific γδ T cells. We found that the CDR3δ sequences of hMSH2-specific γδ T cells displayed limited diversity, while the length and germline gene usage showed no differences compared with whole CDR3δ immune repertoire. There are more hydrophilic amino acids in P/N insert of hMSH2-specific γδ T cells including the more conserved amino acid at the position 97. Our results offer clues to understanding antigen recognition pattern of γδ T cells to stress-induced hMSH2 of tumor cells and also the mechanism of γδT cell-mediated tumor immune surveillance.

The Jekyll and Hyde story of IL17-Producing γδT Cells

In comparison to conventional αβT cells, γδT cells are considered as specialized T cells based on their contributions in regulating immune response. γδT cells sense early environmental signals and initiate local immune-surveillance. The development of functional subtypes of γδT cells takes place in the thymus but they also exhibit plasticity in response to the activating signals and cytokines encountered in the extrathymic region. Thymic development of Tγδ1 requires strong TCR, CD27, and Skint-1 signals. However, differentiation of IL17-producing γδT cells (Tγδ17) is independent of Skint-1 or CD27 but requires notch signaling along with IL6 and TGFβ cytokines in the presence of weak TCR signal. In response to cytokines like IL23, IL6, and IL1β, Tγδ17 outshine Th17 cells for early activation and IL17 secretion. Despite expressing similar repertoire of lineage transcriptional factors, cytokines, and chemokine receptors, Tγδ17 cells differ from Th17 in spatial and temporal fashion. There are compelling reasons to consider significant role of Tγδ17 cells in regulating inflammation and thereby disease outcome. Tγδ17 cells regulate mobilization of innate immune cells and induce keratinocytes to secrete anti-microbial peptides thus exhibiting protective functions in anti-microbial immunity. In contrast, dysregulated Tγδ17 cells inhibit Treg cells, exacerbate autoimmunity, and are also known to support carcinogenesis by enhancing angiogenesis. The mechanism associated with this dual behavior of Tγδ17 is not clear. To exploit, Tγδ17 cells for beneficial use requires comprehensive analysis of their biology. Here, we summarize the current understanding on the characteristics, development, and functions of Tγδ17 cells in various pathological scenarios.

Endoplasmic reticulum chaperones and their roles in the immunogenicity of cancer vaccines

The endoplasmic reticulum (ER) is a major site of passage for proteins en route to other organelles, to the cell surface, and to the extracellular space. It is also the transport route for peptides generated in the cytosol by the proteasome into the ER for loading onto major histocompatibility complex class I (MHC I) molecules for eventual antigen presentation at the cell surface. Chaperones within the ER are critical for many of these processes; however, outside the ER certain of those chaperones may play important and direct roles in immune responses. In some cases, particular ER chaperones have been utilized as vaccines against tumors or infectious disease pathogens when purified from tumor tissue or recombinantly generated and loaded with antigen. In other cases, the cell surface location of ER chaperones has implications for immune responses as well as possible tumor resistance. We have produced heat-shock protein/chaperone protein-based cancer vaccines called “chaperone-rich cell lysate” (CRCL) that are conglomerates of chaperones enriched from solid tumors by an isoelectric focusing technique. These preparations have been effective against numerous murine tumors, as well as in a canine with an advanced lung carcinoma treated with autologous CRCL. We also published extensive proteomic analyses of CRCL prepared from human surgically resected tumor samples. Of note, these preparations contained at least 10 ER chaperones and a number of other residents, along with many other chaperones/heat-shock proteins. Gene ontology and network analyses utilizing these proteins essentially recapitulate the antigen presentation pathways and interconnections. In conjunction with our current knowledge of cell surface/extracellular ER chaperones, these data collectively suggest that a systems-level view may provide insight into the potent immune stimulatory activities of CRCL with an emphasis on the roles of ER components in those processes.

Insights into the Relationship between Toll Like Receptors and Gamma Delta T Cell Responses

The tumor microenvironment is an important aspect of cancer biology that contributes to tumor initiation, tumor progression and responses to therapy. The composition and characteristics of the tumor microenvironment vary widely and are important in determining the anti-tumor immune response. Successful immunization requires activation of both innate and adaptive immunity. Generally, immune system is compromised in patients with cancer due to immune suppression, loss of tumor antigen expression and dysfunction of antigen presenting cells (APC). Thus, therapeutic immunization leading to cancer regression remains a significant challenge. Certain cells of the immune system, including dendritic cells (DCs) and gamma delta (γδ) T cells are capable of driving potent anti-tumor responses. The property of MHC-unrestricted cytotoxicity, high potential of cytokine release, tissue tropism and early activation in infections and malignant disease makes γδ T cells as an emerging candidate for immunotherapy. Various strategies are being developed to enhance anti-tumor immune responses of γδ T cells and DCs one of them is the use of novel adjuvants like toll like receptors (TLR) agonists, which enhance γδ T cell function directly or through DC activation, which has ability to prime γδ T cells. TLR agonists are being used clinically either alone or in combination with tumor antigens and has shown initial success in both enhancing immune responses and eliciting anti-tumor activity. TLR activated γδ T cells and DCs nurture each other's activation. This provides a potent base for first line of defense and manipulation of the adaptive response against pathogens and cancer. The available data provides a strong rationale for initiating combinatorial therapy for the treatment of diseases and this review will summarize the application of adjuvants (TLRs) for boosting immune response of γδ T cells to treat cancer and infectious diseases and their use in combinatorial therapy.

Identification of a new tuberculosis antigen recognized by γδ T cell receptor

The immune protection initiated by γδ T cells plays an important role in mycobacterial infection. The γδ T cells activated by Mycobacterium tuberculosis-derived nonpeptidic, phosphorylated biometabolites (phosphoantigens) provide only partial immune protection against mycobacterium, while evidence has suggested that protein antigen-activated γδ T cells elicit effective protective immune responses. To date, only a few distinct mycobacterial protein antigens have been identified. In the present study, we screened protein antigens recognized by γδ T cells using cells transfected with the predominant pulmonary tuberculosis γδ T cell receptor (TCR) CDR3 fragment. We identified two peptides, TP1 and TP2, which not only bind to the pulmonary tuberculosis predominant γδ TCR but also effectively activate γδ T cells isolated from pulmonary tuberculosis patients. Moreover, 1-deoxy-d-xylulose 5-phosphate synthase 2 (DXS2), the TP1-matched mycobacterial protein, was confirmed as a ligand for the γδ TCR and was found to activate γδ T cells from pulmonary tuberculosis patients. The extracellular region (extracellular peptide [EP]) of Rv2272, a TP2-matched mycobacterial transmembrane protein, was also shown to activate γδ T cells from pulmonary tuberculosis patients. Both DXS2- and EP-expanded γδ T cells from pulmonary tuberculosis patients could secrete gamma interferon (IFN-γ) and monocyte chemoattractant protein 1 (MCP-1), which play important roles in mediating cytotoxicity against mycobacterium and stimulating monocyte chemotaxis toward the site of infection. In conclusion, our study identified novel mycobacterial protein antigens recognized by γδ TCR cells that could be candidates for the development of vaccines or adjuvants against mycobacterium infection.

HSP72 and gp96 in gastroenterological cancers

Heat shock protein 72 (HSP72) and glycoprotein 96 (gp96) are highly expressed in cancer tissues. Recent studies indicate the possible roles of HSP72 and gp96 in the development and progression of gastrointestinal carcinomas but detailed mechanisms are still ambiguous. Human esophageal cancer, gastric cancer, colon cancer and liver cancer are common gastrointestinal malignant carcinomas in the world. The studies indicated that there existed a significant correlation between the expression of HSP72, gp96 and the development and progression of digestive carcinomas. HSP72 and gp96 expression were significantly associated with the presence of tumor infiltration, lymph node and remote metastasis. Interestingly, studies have found that HSP72 chaperoned alpha-fetoprotein (AFP), HBx in hepatocellular carcinoma, and CD44 in colonic carcinomas. The further researches demonstrated that HSP72-AFP or gp96-AFP recombined vaccine could elicit specific anti-tumor immunity. The high-level expression of HSP72 and gp96 may be not only used as diagnostic or prognostic markers for gastrointestinal carcinomas but also as better immunotherapeutic vaccines in the cancers.

γδ T cells attenuate bleomycin-induced fibrosis through the production of CXCL10

γδ T cells are a subset of T cells associated with epithelial mucosal tissues and play a prominent role in both promoting and dampening inflammatory responses to pathogens; in addition, they strongly mediate epithelial repair. By using a bleomycin model of pulmonary fibrosis, we found that γδ T-cell populations dramatically increased after bleomycin administration. To determine the importance of these cells, we exposed mice lacking the δ chain of the γδ T-cell receptor (γδ knockout [KO]) to bleomycin. Pulmonary fibrosis was more severe in γδ KO mice, as measured by collagen deposition (hydroxyproline) and histopathological features. Furthermore, there was no evidence of resolution of the fibrotic response up to 45 days after bleomycin therapy. In contrast to control mice, γδ KO mice had decreased concentrations of IL-6, granulocyte colony stimulating factor, chemokine CXC ligand (CXCL) 1, and interferon inducible protein 10/CXCL10. In vitro culture of γδ T cells purified from lungs 17 days after bleomycin exposure (a time of peak influx of these cells) demonstrated that γδ T cells produced substantial quantities of all four of these cytokines, suggesting that γδ T cells are a predominant source of these proteins. To demonstrate that γδ T cells are effector cells in the fibrotic response, we performed adoptive transfer experiments with γδ T cells sorted from bleomycin-treated lungs; these cells were sufficient to resolve fibrosis in γδ KO mice and restore CXCL10 levels comparable to wild-type mice. Furthermore, overexpression of CXCL10 in the lung decreased the severity of fibrosis seen in the γδ KO mice. Finally, adoptive transfer of γδ T cells from CXCL10(-/-) mice failed to reverse the severe fibrosis in γδ KO mice. These results indicate that γδ T cells promote the resolution of fibrosis through the production of CXCL10.

γδ T cell receptor ligands and modes of antigen recognition

T lymphocytes expressing the γδ-type of T cell receptors (TCRs) for antigens contribute to all aspects of immune responses, including defenses against viruses, bacteria, parasites and tumors, allergy and autoimmunity. Multiple subsets have been individualized in humans as well as in mice and they appear to recognize in a TCR-dependent manner antigens as diverse as small non-peptidic molecules, soluble or membrane-anchored polypeptides and molecules related to MHC antigens on cell surfaces, implying diverse modes of antigen recognition. We review here the γδ TCR ligands which have been identified along the years and their characteristics, with emphasis on a few systems which have been extensively studied such as human γδ T cells responding to phosphoantigens or murine γδ T cells activated by allogeneic MHC antigens. We discuss a speculative model of antigen recognition involving simultaneous TCR recognition of MHC-like and non-MHC ligands which could fit with most available data and shares many similarities with the classical model of MHC-restricted antigen recognition for peptides or lipids by T cells subsets with αβ-type TCRs.

Correlation between clinicopathology and expression of heat shock protein 72 and glycoprotein 96 in human esophageal squamous cell carcinoma

Heat shock protein 72 (HSP72) and glycoprotein 96 (gp96) are highly expressed in cancer tissues. Recent studies indicate the possible roles of HSP72 and gp96 in the development and progression of gastrointestinal carcinomas but detailed information is still ambiguous. We investigated the correlation between clinicopathology and expression of HSP72 and gp96 in human esophageal squamous cell carcinoma. The expression of HSP72 and gp96 was studied in 120 human esophageal squamous cell carcinomas with or without metastasis as well as in mucous membrane adjacent to cancers by way of immunohistochemistry. HSP72 immunoreactivities were detected in 112 of 120 primary tumors (93.3%) and in 30 of 120 mucous membranes adjacent to cancers (25.0%). Gp96 detected in esophageal squamous cell carcinoma and inmucous membrane adjacent to cancer was 85.0% and 20.0%, respectively. Both HSP72 and gp96 stained in cytoplasm. HSP72 and gp96 expression in esophageal squamous cell carcinomas withmetastasis was significantly higher than those with nonmetastasis (P < .05). The results indicate that there exists a significant correlation between the expression of HSP72 and gp96 and the progression of esophageal squamous cell carcinomas. HSP72 and gp96 expression were significantly associated with the presence of tumor infiltration, lymph node, and remote metastasis.

Heat shock protein 70 on Neuro2a cells is a putative receptor for Japanese encephalitis virus

Japanese encephalitis virus (JEV) envelope (E) protein has been shown to play a critical role in attachment to cells. However, the receptor interacting with envelope protein has not been conclusively identified. Using mouse neuroblastoma (Neuro2a) cells and purified JEV-E protein in 'Virus Overlay Protein Binding Assay' followed by MALDI-TOF analysis, we identified 'heat shock protein 70' (Hsp70) as a possible receptor for JEV. Indirect immunofluorescence and flow-cytometry analysis demonstrated localization of Hsp70 on Neuro2a cell surface. Co-immunoprecipitation followed by Western blot analysis reconfirmed the interaction between Hsp70 and JEV-E protein. Further, anti-Hsp70 polyclonal-antibodies were able to block JEV entry into Neuro2a cells. Additionally, using the bioinformatic tool - FTDOCK, docking between the proteins was performed. Amongst six interacting structural poses studied one pose involving RGD motif on JEV-E and leucine(539) on Hsp70 displayed stable interaction. These observations indicate that Hsp70 serves as putative receptor for JEV in Neuro2A cells.

Targeting solid tumors via T cell receptor complementarity-determining region 3delta in an engineered antibody

Human Vdelta2 gammadelta T lymphocytes killed multiple solid tumors, even displaying comparable therapeutic efficacy with anti-tumor chemical-cis-platinum in an adoptive experiment in both nude and SCID murine model shown in present study. We previously found that T cell receptor (TCR) gammadelta recognize tumors via complementarity-determining region 3 (CDR3), briefly named as CDR3delta. Based on characteristics of specific binding of CDR3delta to tumor targets, we developed a novel tumor-targeting antibody, whose CDR3 in heavy chain is replaced by CDR3delta sequence derived from human ovarian carcinoma (OEC) infiltrating gammadelta T cells (gammadeltaTILs). This CDR3delta-grafted antibody OT3 exhibited specific binding activities to OEC line SKOV3 both in vitro and in vivo, which included specific binding to several tumor cell lines, interacting with heat shock protein (HSP) 60 and triggering ADCC against tumors in vitro, as well as displaying tumor imaging by radioisotope 99mTc-labeled antibody OT3 in vivo. Moreover, immunotoxin OT3-DT, CDR3delta-grafted antibody OT3 chemically conjugated with diphtheria toxin (DT) showed the anti-tumor effect on the growth of several solid tumors including OEC, cervix adenocarcinoma, hepatocellular carcinoma, and rectum adenocarcinoma to various extents in nude mice. Therefore, we have found and confirmed a novel therapeutic strategy for targeting solid tumors, making use of immune recognition characteristics of gammadelta T cells.

Bioactive food components that enhance gammadelta T cell function may play a role in cancer prevention

Gammadelta T cells are found largely within the epithelium and recognize antigens differently than their alphabeta T cell counterparts. TCR delta-/- knock out mice exhibit a rapid tumor onset, along with increased tumor incidence. Although limited, research demonstrates that nutrients and bioactive food components can influence gammadelta T cell cytotoxicity, cytokine secretion, and proliferative capacity, and the results are nonetheless intriguing. Among other functions, gammadelta T cells play a role in immunosurveillance against malignant cells, as shown by the T cell receptor (TCR)delta-/- knock out mice that exhibit a rapid tumor onset and increased tumor incidence. Some common dietary modifiers of gammadelta T cell numbers or activity are apple condensed tannins, dietary nucleotides, fatty acids, and dietary alkylamines. A recent clinical study demonstrated that ingesting a fruit and vegetable juice concentrate increased the number of circulating gammadelta T cells. Clinical studies also document that the oral consumption of a tea component, L-theanine, enhances gammadelta T cell proliferation and interferon-gamma secretion. The significance of these studies awaits additional examination of the influence of exposures and duration on these and other food components. Adoptive transfer and TCRdelta-/- knock out mice models should be used more extensively to determine the physiological impact of the number and activity of these cells as a function of dietary component exposures. While clarifying the diet and gammadelta T interrelationship may not be simple, the societal implications are enormous.

Immunolocalisation of heat shock protein 72 and glycoprotein 96 in colonic adenocarcinoma

Heat shock protein 72 (HSP72) and glycoprotein 96 (gp96) are highly expressed in cancer tissues. Recent studies indicate the possible roles of HSP72 and gp96 in the development and progression of colonic carcinomas, but detailed information is still ambiguous. In this study, we investigated the correlation between clinical pathology and immunolocalisation of HSP72 and gp96 in human colonic carcinoma. The distribution of HSP72 and gp96 was studied in 160 human colonic carcinomas, with or without metastasis, as well as in mucous membranes adjacent to cancers by means of immunohistochemistry. HSP72 immunoreactivity was detected in 145 of 160 primary tumours (90.6%) and in 44 of 160 mucous membranes adjacent to cancers (27.5%). Gp96 was detected in 81.3% colonic carcinomas and in 13.8% mucous membranes adjacent to cancer. Immunolocalisation of HSP72 and gp96 was mainly cytoplasmic. HSP72 and gp96 immunolabelling was significantly higher in colonic carcinomas with metastasis than in those without metastasis (P<0.05). The results indicate a significant correlation between the immunopositivity of HSP72 and gp96 and the progression of colonic carcinomas. Immunolabelling of HSP72 and gp96 may be useful as diagnostic or prognostic markers in colonic carcinoma.

The heat shock response and chaperones/heat shock proteins in brain tumors: surface expression, release, and possible immune consequences

The heat shock response is a highly conserved "stress response" mechanism used by cells to protect themselves from potentially damaging insults. It often involves the upregulated expression of chaperone and heat shock proteins (HSPs) to prevent damage and aggregation at the proteome level. Like most cancers, brain tumor cells often overexpress chaperones/HSPs, probably because of the stressful atmosphere in which tumors reside, but also because of the benefits of HSP cytoprotection. However, the cellular dynamics and localization of HSPs in either stressed or unstressed conditions has not been studied extensively in brain tumor cells. We have examined the changes in HSP expression and in cell surface/extracellular localization of selected brain tumor cell lines under heat shock or normal environments. We herein report that brain tumor cell lines have considerable heat shock responses or already high constitutive HSP levels; that those cells express various HSPs, chaperones, and at least one cochaperone on their cell surfaces; and that HSPs may be released into the extracellular environment, possibly as exosome vesicular content. In studies with a murine astrocytoma cell line, heat shock dramatically reduces tumorigenicity, possibly by an immune mechanism. Additional evidence indicative of an HSP-driven immune response comes from immunization studies using tumor-derived chaperone protein vaccines, which lead to antigen-specific immune responses and reduced tumor burden in treated mice. The heat shock response and HSPs in brain tumor cells may represent an area of vulnerability in our attempts to treat these recalcitrant and deadly tumors.

Correlation between clinicopathology and expression of heat shock protein 72 and glycoprotein 96 in human gastric adenocarcinoma

Heat shock protein 72 (HSP72) and glycoprotein 96 (gp96) are highly expressed in cancer tissues. Recent studies indicate the possible roles of HSP72 and gp96 in the development and progression of gastric carcinomas but detailed information is still ambiguous. In this study, we investigated the correlation between clinicopathology and expression of HSP72 and gp96 in human gastric carcinoma. The expression of HSP72 and gp96 was studied in 60 human gastric carcinomas with or without metastasis as well as in mucous membrane adjacent to cancers by way of immunohistochemistry. HSP72 immunoreactivities were detected in 54 of 60 primary tumors (90.0%) and in 22 of 60 mucous membranes adjacent to cancers (36.7%). Likewise, gp96 immunoreactivities were detected in 49 cases of gastric carcinoma (81.7%) and in 15 samples of mucous membrane adjacent to cancer (25.0%). Both HSP72 and gp96 were stained in cytoplasm. HSP72 and gp96 expression in colonic carcinomas with metastasis was significantly higher than those with non-metastasis (p < 0.05). The results indicate that there exists a significant correlation between the expression of HSP72 and gp96 and the progression of gastric carcinomas. The high-level expression of HSP72 and gp96 may be used as diagnostic or prognostic markers for gastric carcinoma.

Interaction between heat shock protein 72 and alpha-fetoprotein in human hepatocellular carcinomas

BACKGROUND

AFP in adult serum often signals pathological conditions, particularly the presence of hepatocellular carcinoma (HCC) and germ cell tumors containing yolk sac cell elements. Heat shock protein 72 (HSP72) as a molecular chaperone has been confirmed to overexpress in epithelial carcinoma cells. There may be a possible correlation between the expression of HSP72 and AFP during the growth and differentiation of hepatocellular carcinoma cells. We investigated the interaction between heat shock protein 72 (HSP72) and alpha-fetoprotein (AFP) in human hepatocellular carcinomas.

METHODS

The expression and localization of HSP72 and AFP in human hepatocellular carcinomas were determined by immunohistochemistry and confocal laser microscopy. The interaction between HSP72 and AFP in hepatocellular carcinoma cells was analyzed by immunoprecipitation and Western immunoblots.

RESULTS

Hepatocellular carcinoma synchronously co-expressed higher level of HSP72 and AFP than in adjacent normal liver tissues. HSP72 were stained in cell nuclei and cytoplasm respectively, while AFP stained in cell plasma. Based on Western blotting methods, AFP was detected in the immunoprecipitate of anti-HSP72 monoclonal antibody (mAb), while HSP72 existed in the immunoprecipitate of anti-AFP mAb.

CONCLUSIONS

HSP72 and AFP expression are higher in hepatocellular carcinoma tissues. HSP72 was associated with alpha-fetoprotein in human hepatocellular carcinoma cells. The interaction between HSP72 and AFP in human hepatocellular carcinoma cells can be a new route for studying the pathogenesis and immunotherapy of hepatocellular carcinoma.