γδ T Cells Cross-Link Innate and Adaptive Immunity in Mycobacterium tuberculosis Infection

Protective immunity against mycobacterial infections such as Mycobacterium tuberculosis is mediated by interactions between specific T cells and activated antigen presenting cells. To date, many aspects of mycobacterial immunity have shown that innate cells could be the key elements that substantially may influence the subsequent adaptive host response. During the early phases of infection, innate lymphocyte subsets play a pivotal role in this context. Here we summarize the findings of recent investigations on γδ T lymphocytes and their role in tuberculosis immunity

Distribution, function and predictive value of tumor-infiltrating γδ T lymphocytes

Although γδ T cells are known to exert both tumor-preventing and tumor-promoting activity, there is still little information on the functional characteristics and clinical significance of γδ T cells isolated from the tumor site. In a recent study, we have investigated the distribution of different γδ T-cell populations in melanoma and their impact on disease outcom

Current Advances in γδ T Cell-Based Tumor Immunotherapy

γδ T cells are a minor population (~5%) of CD3 T cells in the peripheral blood, but abound in other anatomic sites such as the intestine or the skin. There are two major subsets of γδ T cells: those that express Vd1 gene, paired with different Vγ elements, abound in the intestine and the skin, and recognize the major histocompatibility complex (MHC) class I-related molecules such as MHC class I-related molecule A, MHC class I-related molecule B, and UL16-binding protein expressed on many stressed and tumor cells. Conversely, γδ T cells expressing the Vδ2 gene paired with the Vγ9 chain are the predominant (50-90%) γδ T cell population in the peripheral blood and recognize phosphoantigens (PAgs) derived from the mevalonate pathway of mammalian cells, which is highly active upon infection or tumor transformation. Aminobisphosphonates (n-BPs), which inhibit farnesyl pyrophosphate synthase, a downstream enzyme of the mevalonate pathway, cause accumulation of upstream PAgs and therefore promote γδ T cell activation. γδ T cells have distinctive features that justify their utilization in antitumor immunotherapy: they do not require MHC restriction and are less dependent that aà T cells on co-stimulatory signals, produce cytokines with known antitumor effects as interferon-? and tumor necrosis factor-a and display cytotoxic and antitumor activities in vitro and in mouse models in vivo. Thus, there is interest in the potential application of γδ T cells in tumor immunotherapy, and several small-sized clinical trials have been conducted of γδ T cell-based immunotherapy in different types of cancer after the application of PAgs or n-BPs plus interleukin-2 in vivo or after adoptive transfer of ex vivo-expanded γδ T cells, particularly the Vγ9Vδ2 subset. Results from clinical trials testing the efficacy of any of these two strategies have shown that γδ T cell-based therapy is safe, but long-term clinical results to date are inconsistent. In this review, we will discuss the major achievements and pitfalls of the γδ T cell-based immunotherapy of cancer

Combining conventional chemotherapy and γδ T cell-based immunotherapy to target cancer-initiating cells.

Colon cancer comprises a small population of cancer initiating stem cells (CIC) that is responsible for tumor maintenance and resistance to anti-cancer therapies, possibly allowing for tumor recapitulation once treatment stops. Combinations of immune-based therapies with chemotherapy and other anti-tumor agents may be of significant clinical benefit in the treatment of colon cancer. However, cellular immune-based therapies have not been experimented yet in the population of colon CICs. Here, we demonstrate that treatment with low concentrations of commonly used chemotherapeutic agents, 5-fluorouracyl and doxorubicin, sensitize colon CICs to Vγ9Vδ2 T cell cytotoxicity. Vγ9Vδ2 T cell cytotoxicity was largely mediated by TRAIL interaction with DR5, following NKG2D-dependent recognition of colon CIC targets. We conclude that in vivo activation of Vγ9Vδ2 T cells or adoptive administration of ex-vivo expanded Vγ9Vδ2 T cells at suitable intervals after chemotherapy may substantially increase anti-tumor activities and represent a novel strategy for colon cancer immunotherapy

Chemotherapy Sensitizes Colon Cancer Initiating Cells to Vc9Vd2 T Cell-Mediated Cytotoxicity

Colon cancer comprises a small population of cancer initiating stem cells (CIC) that is responsible for tumor maintenance and resistance to anti-cancer therapies, possibly allowing for tumor recapitulation once treatment stops. Combinations of immune-based therapies with chemotherapy and other anti-tumor agents may be of significant clinical benefit in the treatment of colon cancer. However, cellular immune-based therapies have not been experimented yet in the population of colon CICs. Here, we demonstrate that treatment with low concentrations of commonly used chemotherapeutic agents, 5- fluorouracyl and doxorubicin, sensitize colon CICs to Vc9Vd2 T cell cytotoxicity. Vc9Vd2 T cell cytotoxicity was largely mediated by TRAIL interaction with DR5, following NKG2D-dependent recognition of colon CIC targets. We conclude that in vivo activation of Vc9Vd2 T cells or adoptive administration of ex-vivo expanded Vc9Vd2 T cells at suitable intervals after chemotherapy may substantially increase anti-tumor activities and represent a novel strategy for colon cancer immunotherapy

Role of exosomes released by chronic myelogenous leukemia cells in angiogenesis

The present study is designed to assess if exosomes released from Chronic Myelogenous Leukemia (CML) cells may modulate angiogenesis. We have isolated and characterized the exosomes generated from LAMA84 CML cells and demonstrated that addition of exosomes to human vascular endothelial cells (HUVEC) induces an increase of both ICAM-1 and VCAM-1 cell adhesion molecules and interleukin-8 expression. The stimulation of cell-cell adhesion molecules was paralleled by a dose-dependent increase of adhesion of CML cells to a HUVEC monolayer. We further showed that the treatment with exosomes from CML cells caused an increase in endothelial cell motility accompanied by a loss of VE-cadherin and β-catenin from the endothelial cell surface. Functional characterization of exosomes isolated from CML patients confirmed the data obtained with exosomes derived from CML cell line. CML exosomes caused reorganization into tubes of HUVEC cells cultured on Matrigel. When added to Matrigel plugs in vivo, exosomes induced ingrowth of murine endothelial cells and vascularization of the Matrigel plugs. Our results suggest for the first time that exosomes released from CML cells directly affect endothelial cells modulating the process of neovascularization

Humoral and Cell-Mediated Responses to SARS-CoV-2 Vaccination in a Cohort of Immunodeficient Patients

This study delves into the intricate landscape of SARS-CoV-2 vaccine response in immunodeficient patients, focusing on the dynamics of both humoral and cell-mediated immunity. The cohort includes patients with common variable immunodeficiency (CVI), agammaglobulinemia (XLA), and combined immunodeficiency (CI). The findings reveal varying degrees of antibody production, with XLA patients exhibiting no measurable response but displaying a robust T-cell-mediated response. The study emphasizes the importance of considering both arms of the immune system in assessing vaccine immunogenicity, particularly in the context of immunodeficiency. The results challenge conventional measures of vaccine efficacy only based on antibody titers, highlighting the need for a more comprehensive understanding of the immune response in this vulnerable population. This research contributes valuable insights to guide clinical decisions regarding vaccination strategies, booster doses, and overall protection in immunodeficient individuals

The Phenotypic Characterization of the Oldest Italian Man from December 28, 2020, to September 23, 2021, A.T., Strengthens the Idea That the Immune System can Play a Key Role in the Attainment of Extreme Longevity

: In this paper, we present demographic, clinical, anamnestic, cognitive, and functional data, as well as haematological, haematochemical, immunological, and genetic parameters of an exceptional individual: A.T., a semi-supercentenarian who held the title of the oldest living Italian male centenarian from 28 December 2020, to 23 September 2021. The purpose of this study is to provide fresh insights into extreme phenotypes, with a particular focus on immune-inflammatory parameters. To the best of our knowledge, this study represents the first phenotypic investigation of a semi-supercentenarian, illustrating both INFLA-score, a metric designed to assess the cumulative impact of inflammatory markers and indicators of age-related immune phenotype (ARIP), recognized as significant gauges of biological ageing. The aim of this study was, indeed, to advance our understanding of the role of immune-inflammatory responses in achieving extreme longevity. The results of laboratory tests, as well as clinical history and interview data, when compared to the results of our recent study on Sicilian centenarians, demonstrate an excellent state of health considering his age. Consistent with previous studies, we observed increased IL-6 inflammatory markers and INFLA score in A.T. More interestingly, the semi-supercentenarian showed values of ARIP indicators such as naïve CD4+ cells, CD4+/CD8+ ratio, and CD4+TN/TM ratio in the range of young adult individuals, suggesting that his immune system's biological age was younger than the chronological one. The results support the notion that the immune system can play a role in promoting extreme longevity. However, this does not rule out the involvement of other body systems or organs in achieving extreme longevity

Sicilian Semi- and Supercentenarians: Age-related NK Cell Immunophenotype and Longevity Trait Definition

: The immune system of semi- and supercentenarians (i.e., the oldest centenarians) is believed to have peculiar characteristics that enable them to reach extreme longevity in a relatively healthy state. Therefore, in previous papers, we investigated, through flow cytometry, variations in the percentages of the main subsets of Tαβ and Tγδ cells in a Sicilian cohort of 28 women and 26 men (age range 19-110 years), including 11 long-living individuals (>90 years old) and 8 oldest centenarians. These investigations suggested that some observed immunophenotypic changes may contribute to the extreme longevity of the oldest centenarians. In the present study, to further characterize the immunophenotype of the oldest centenarians, we examined the percentages of Natural Killer (NK) cells identified as CD3-CD56 + CD16+ in the previously described Sicilian cohort. We found a highly significant increase in NK cell percentages with age. When stratified by gender, this significant increase with age was maintained in both sexes, with higher significance observed in males. Our findings on NK cells, together with the previously obtained results, discussed in the context of the literature, suggest that these changes are not unfavourable for centenarians, including the oldest ones, supporting the hypothesis that immune aging should be considered as a differential adaptation rather than a general immune alteration. These adapted immune mechanisms allow the oldest centenarians to successfully adapt to a history of insults and achieve remarkable longevity

Role of the chemokine decoy receptor D6 in balancing inflammation, immune activation, and antimicrobial resistance in Mycobacterium tuberculosis infection

D6 is a decoy and scavenger receptor for inflammatory CC chemokines. D6-deficient mice were rapidly killed by intranasal administration of low doses of Mycobacterium tuberculosis. The death of D6−/− mice was associated with a dramatic local and systemic inflammatory response with levels of M. tuberculosis colony-forming units similar to control D6-proficient mice. D6-deficient mice showed an increased numbers of mononuclear cells (macrophages, dendritic cells, and CD4 and CD8 T lymphocytes) infiltrating inflamed tissues and lymph nodes, as well as abnormal increased concentrations of CC chemokines (CCL2, CCL3, CCL4, and CCL5) and proinflammatory cytokines (tumor necrosis factor α, interleukin 1β, and interferon γ) in bronchoalveolar lavage and serum. High levels of inflammatory cytokines in D6−/− infected mice were associated with liver and kidney damage, resulting in both liver and renal failure. Blocking inflammatory CC chemokines with a cocktail of antibodies reversed the inflammatory phenotype of D6−/− mice but led to less controlled growth of M. tuberculosis. Thus, the D6 decoy receptor plays a key role in setting the balance between antimicrobial resistance, immune activation, and inflammation in M. tuberculosis infection