Accelerated T-Cell Immunosenescence in Cytomegalovirus-Seropositive Individuals After Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

Cytomegalovirus (CMV) infection is a major driver of accelerated immunosenescence related to CD28null T cell expansion. CMV infection and these proatherogenic T cells have been independently associated with cardiovascular disease and coronavirus disease 2019 (COVID-19) severity. We investigated the potential contribution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to immunosenescence and its relationship with CMV. Innate and adaptive immune subpopulations from individuals with mild or asymptomatic SARS-CoV-2 infection (mCOVID-19) and healthy donors were immunophenotyped. A significant increase in CD28nullCD57+CX3CR1+ T cell percentages (CD4+ [P ≤ .01], CD8+ [P ≤ .01], and TcRγδ (CD4-CD8-) [P ≤ .001]) was found in unnvaccinated CMV-seropositive mCOVID-19 individuals stable up to 12 months after infection. This expansion did not occur in CMV-seronegative mCOVID-19 individuals or in CMV-seropositive individuals infected after SARS-CoV-2 vaccination. There were no significant differences between mCOVID-19 and aortic stenosis groups. Thus, individuals coinfected with SARS-CoV-2 and CMV have accelerated T cell senescence, which might lead to an increased risk of cardiovascular disease.

Natural Killer T-like Cells: Immunobiology and Role in Disease.

CD56+ T cells are generally recognized as a distinct population of T cells and are categorized as NKT-like cells. Although our understanding of NKT-like cells is far from satisfactory, it has been shown that aging and a number of disease situations have impacted these cells. To construct an overview of what is currently known, we reviewed the literature on human NKT-like cells. NKT-like cells are highly differentiated T cells with "CD1d-independent" antigen recognition and MHC-unrestricted cell killing. The genesis of NKT-like cells is unclear; however, it is proposed that the acquisition of innate characteristics by T cells could represent a remodeling process leading to successful aging. Additionally, it has been shown that NKT-like cells may play a significant role in several pathological conditions, making it necessary to comprehend whether these cells might function as prognostic markers. The quantification and characterization of these cells might serve as a cutting-edge indicator of individual immune health. Additionally, exploring the mechanisms that can control their killing activity in different contexts may therefore result in innovative therapeutic alternatives in a wide range of disease settings.

Current progress in NK cell biology and NK cell-based cancer immunotherapy.

A better understanding of the complex interactions between the immune system and tumour cells from different origins has opened the possibility to design novel procedures of antitumoral immunotherapy. One of these novel approaches is based on the use of autologous or allogeneic natural killer (NK) cells to treat cancer. In the last decade, different strategies to activate NK cells and their use in adoptive NK cell-based therapy have been established. Although NK cells are often considered as a uniform cell population, several phenotypic and functionally distinct NK cells subsets exist in healthy individuals, that are differentially affected by ageing or by apparently innocuous viruses such as cytomegalovirus (CMV). In addition, further alterations in the expression of activating and inhibitory receptors are found in NK cells from cancer patients, likely because of their interaction with tumour cells. Thus, NK cells represent a promising strategy for adoptive immunotherapy of cancer already tested in phase 1/2 clinical trials. However, the existence of NK cell subpopulations expressing different patterns of activating and inhibitory receptors and different functional capacities, that can be found to be altered not only in cancer patients but also in healthy individuals stratified by age or CMV infection, makes necessary a personalized definition of the procedures used in the selection, expansion, and activation of the relevant NK cell subsets to be successfully used in NK cell-based immunotherapy.

Modulation of NK cells with checkpoint inhibitors in the context of cancer immunotherapy.

The incidence of some types of tumours has increased progressively in recent years and is expected to continue growing in the coming years due in part to the aging of the population. The design of new therapies based on natural killer (NK) cells opens new possibilities especially for the treatment of elderly patients who are particularly susceptible to the toxicity of conventional chemotherapy treatments. In recent years, the potential use of NK cells in cancer immunotherapy has been of great interest thanks to advances in the study of NK cell biology. The identification of key points (checkpoints) in the activation of NK cells that can be regulated by monoclonal antibodies has allowed the design of new therapeutic strategies based on NK cells. However, there are still limitations for its use and the first clinical trials blocking KIR inhibitory receptors have shown little efficacy by inhibiting the maturation of NK cells. Blockade of other inhibitory receptors such as TIGIT, TIM3, LAG3 and PD1 may represent novel strategies to increase NK function in cancer patients. Altogether, the identification of NK cell and tumour cell markers of resistance or susceptibility to the action of NK cells will contribute to identifying those patients that will most likely benefit from NK cell-based immunotherapy.

Immunosenescence: limitations of natural killer cell-based cancer immunotherapy.

Cancer is primarily considered a disease of old age. Immunosenescence refers to the age-associated changes in the immune system, and its contribution to the increased risk of cancer in old individuals has been discussed for many years. Natural killer (NK) cells are cytotoxic innate immune cells specialized in defence against tumour and virus-infected cells. NK cell cytotoxicity is the result of a fine balance between activating and inhibitory receptors. Several activating receptors have been identified that recognize different ligands frequently found over-expressed on tumour cells or virus-infected cells. The most important NK cell inhibitory receptors interact with major histocompatibility complex class I molecules expressed on almost all nucleated cells preventing NK cell-mediated lysis of healthy cells. NK cell immunosenescence is characterized by a redistribution of NK cell subsets, a diminished expression of several activating receptors and lower per-cell cytotoxicity. Altered expression of activating receptors has also been described in young and elderly cancer patients probably due to chronic exposure to ligands on tumour cells. Thus, the effect of both age and cancer may act synergistically to diminish NK cell-mediated tumour immunosurveillance. Different strategies harnessing the power of NK cells to target tumour cells have been designed including adoptive therapy with autologous or allogeneic expanded NK cells. In addition, checkpoint blockade of inhibitory receptors and the use of agonist antibodies to stimulate activating receptors are emerging areas of research. In this context, the effect of immunosenescence should be considered to improve the efficiency of cancer immunotherapy.

Evaluation of antigen-induced synovitis in a porcine model: Immunological, arthroscopic and kinetic studies.

BACKGROUND: Synovitis is an inflammation-related disease linked to rheumatoid arthritis, osteoarthritis, infections and trauma. This inflammation is accompanied by immune cells infiltration which initiates an inflammatory response causing pain, discomfort and affecting the normal joint function. The treatment of synovitis is based on the administration of anti-inflammatory drugs or biological agents such as platelet rich plasma and mesenchymal stem cells. However, the evaluation and validation of more effective therapies of synovitis requires the establishment of clinically relevant animal models. RESULTS: In this study, Large White pigs were pre-immunized to evaluate an antigen-induced synovitis. The immune monitoring of synovial fluids in this model allowed us the identification of IL-12p40 and T cell subsets as immune biomarkers. Moreover, the evolution of synovitis was performed by arthroscopic procedures and kinetic analysis. In summary, this paper describes an animal model of antigen-induced synovitis to be used in the evaluation of anti-inflammatory therapies. CONCLUSIONS: The novelty of this paper lies in the development of a clinically relevant model of synovitis which permits the simultaneous evaluation of synovitis from an immunological, surgical and kinetic point of view.

Effect of Cytomegalovirus (CMV) and Ageing on T-Bet and Eomes Expression on T-Cell Subsets.

The differential impact of ageing and cytomegalovirus (CMV) latent infection on human T-cell subsets remains to some extent controversial. The purpose of this study was to analyse the expression of the transcription factors T-bet and Eomes and CD57 on CD4+, CD4hiCD8lo and CD8+ T-cell subsets in healthy individuals, stratified by age and CMV serostatus. The percentage of CD4+ T-cells expressing T-bet or Eomes was very low, in particular in CD4+ T-cells from young CMV-seronegative individuals, and were higher in CMV-seropositive older individuals, in both CD57- and CD57+ CD4+ T-cells. The study of the minor peripheral blood double-positive CD4hiCD8lo T-cells showed that the percentage of these T-cells expressing both Eomes and T-bet was higher compared to CD4+ T-cells. The percentage of CD4hiCD8lo T-cells expressing T-bet was also associated with CMV seropositivity and the coexpression of Eomes, T-bet and CD57 on CD4hiCD8lo T-cells was only observed in CMV-seropositive donors, supporting the hypothesis that these cells are mature effector memory cells. The percentage of T-cells expressing Eomes and T-bet was higher in CD8+ T-cells than in CD4+ T-cells. The percentages of CD8+ T-cells expressing Eomes and T-bet increased with age in CMV-seronegative and -seropositive individuals and the percentages of CD57- CD8+ and CD57+ CD8+ T-cells coexpressing both transcription factors were similar in the different groups studied. These results support that CMV chronic infection and/or ageing are associated to the expansion of highly differentiated CD4+, CD4hiCD8lo and CD8+ T-cells that differentially express T-bet and Eomes suggesting that the expression of these transcription factors is essential for the generation and development of an effector-memory and effector T lymphocytes involved in conferring protection against chronic CMV infection.

Natural killer cell immunosenescence in acute myeloid leukaemia patients: new targets for immunotherapeutic strategies?

Several age-associated changes in natural killer (NK) cell phenotype have been reported that contribute to the defective NK cell response observed in elderly patients. A remodelling of the NK cell compartment occurs in the elderly with a reduction in the output of immature CD56(bright) cells and an accumulation of highly differentiated CD56(dim) NK cells. Acute myeloid leukaemia (AML) is generally a disease of older adults. NK cells in AML patients show diminished expression of several activating receptors that contribute to impaired NK cell function and, in consequence, to AML blast escape from NK cell immunosurveillance. In AML patients, phenotypic changes in NK cells have been correlated with disease progression and survival. NK cell-based immunotherapy has emerged as a possibility for the treatment of AML patients. The understanding of age-associated alterations in NK cells is therefore necessary to define adequate therapeutic strategies in older AML patients.

Innate immunosenescence: effect of aging on cells and receptors of the innate immune system in humans.

Components of the innate immune response, including neutrophils and macrophages, are the first line of defense against infections. Their role is to initiate an inflammatory response, phagocyte and kill pathogens, recruit natural killer cells (NK), and facilitate the maturation and migration of dendritic cells that will initiate the adaptive immune response. Extraordinary advances have been made in the last decade on the knowledge of the receptors and mechanisms used by cells of the innate immunity not only to sense and eliminate the pathogen but also to communicate each other and collaborate with cells of adaptive immunity to mount an effective immune response. The analysis of innate immunity in elderly humans has evidenced that aging has a profound impact on the phenotype and functions of these cells. Thus altered expression and/or function of innate immunity receptors and signal transduction leading to defective activation and decreased chemotaxis, phagocytosis and intracellular killing of pathogens have been described. The phenotype and function of NK cells from elderly individuals show significant changes that are compatible with remodeling of the different NK subsets, with a decrease in the CD56bright subpopulation and accumulation of the CD56dim cells, in particular those differentiated NK cells that co-express CD57, as well as a decreased expression of activating natural cytotoxicity receptors. These alterations can be responsible of the decreased production of cytokines and the lower per-cell cytotoxicity observed in the elderly. Considering the relevance of these cells in the initiation of the immune response, the possibility to reactivate the function of innate immune cells should be considered in order to improve the response to pathogens and to vaccination in the elderly.

Expression of NKp30, NKp46 and DNAM-1 activating receptors on resting and IL-2 activated NK cells from healthy donors according to CMV-serostatus and age.

Human natural killer (NK) cells are innate lymphoid cells with capacity to kill tumor cells and virus-infected cells. According to the expression of CD56 and CD16 several NK cell subsets have been identified, a major CD56dimCD16+ subpopulation characterized by higher cytotoxic capacity, two CD56bright subsets (CD16-and CD16+) that represent different maturation stages and the fourth CD56-CD16+ subset that correspond to activated dysfunctional NK cells. Previous studies have shown quantitative changes in the frequency, phenotype and distribution of NK cell subsets depending on CMV-serostatus and age. We have analyzed the expression of NKp30, NKp46 and DNAM-1 NK activating receptors on resting and IL-2 activated NK cells from CMV-seronegative and seropositive healthy young donors and from CMV-seropositive elderly individuals. Our results showed that CMV-serostatus of healthy young donors is associated with phenotypic differences on both CD56bright and CD56dim NK cells with an increase of NKp46 and a decrease of NKp30 expression respectively. A reduced expression of DNAM-1 related to ageing and a lower NKp30 expression associated with CMV-seropositivity were observed. The expression of NKp46 and NKp30 was lower in CD57+ NK cells while the expression of DNAM-1 was increased. In vitro NK cell activation by IL-2 increased the expression of NKp46 and NKp30. In summary, both age and CMV-serostatus influence the expression of these cytotoxicity activating receptors that will have functional consequences. In elderly donors is difficult to isolate age from the effect of chronic CMV infection since in our study all elderly donors were CMV-seropositive. The possibility of modulating the expression of these activating receptors by cytokines such as IL-2 may open new opportunities for improving age-associated deterioration of NK cell function.

Melatonin induces calcium mobilization and influences cell proliferation independently of MT1/MT2 receptor activation in rat pancreatic stellate cells.

Melatonin, the product of the pineal gland, possesses antioxidant, anti-inflammatory, and antitumor properties in different tissues, in addition to its role as regulator of biological rhythms. In this study, the effects of pharmacological concentrations of melatonin (1 µM-1 mM) on pancreatic stellate cells (PSCs) have been examined. Cell viability was studied using AlamarBlue® test. Cell-type specific markers and total amylase content were analyzed by immunocytochemistry and colorimetric methods, respectively. Changes in intracellular free Ca(2+) concentration were followed by fluorimetric analysis of fura-2-loaded cells. The cellular red-ox state was monitored following CM-H2DCFDA-derived fluorescence. Determination of the activation of p44/42 mitogen-activated protein kinase (MAPK), SAPK/JNK and p38 was measured by Western blot analysis. Our results show that PSCs viability decreased in the presence of 100 µM or 1 mM melatonin. However, in the presence of 1 or 10 µM melatonin, no changes in cell viability were observed. Melatonin MT1 and MT2 receptors could not be detected. Melatonin induced Ca(2+) mobilization from intracellular pools. In the presence of melatonin, activation of crucial components of MAPKs pathway was noticed. Finally, the indole did not change the oxidative state of PSCs, but exerted a protective effect against H2O2-induced oxidation. We conclude that melatonin, at pharmacological concentrations, might regulate cellular proliferation of PSCs independently of specific plasma membrane receptors.

Cytokine profiles in acute myeloid leukemia patients at diagnosis: survival is inversely correlated with IL-6 and directly correlated with IL-10 levels.

BACKGROUND: Several evidences support the existence of cytokine deregulation in acute myeloid leukemia (AML) patients that may be associated with pathogenesis, disease progression and patient survival. METHODS: In the present study, we analyzed plasma levels of pro- and anti-inflammatory cytokines in AML patients and age-matched healthy donors. TNF-α, IL-6, IL-1ß, IL-2, IFN-γ, IL-17A, IL-12p70, IL-8, IL-10, IL-4 and IL-5 were analyzed using fluorescent bead-based technology and TGF-ß by ELISA technique. Because age-associated differences in cytokine profiles have been described, patients and healthy individuals were divided into two age groups: up to 65 years and over 65 years. RESULTS: Our results showed that plasma TNF-α, IL-6 and IL-10 levels were higher in AML patients from both groups of age. IL-8 was increased in AML patients less than 65 years while the plasma concentrations of IL-4, IL-5 and IL-12p70 were significantly higher only in elderly AML patients compared with aged-matched healthy controls. Moreover, plasma levels of IL-6 and IL-10 were associated with patient survival and event-free survival. CONCLUSIONS: An aberrant production of the pro-inflammatory cytokines IL-6 and TNF-α and the anti-inflammatory cytokine IL-10 is observed in AML patients. Low levels of IL-6 and high levels of IL-10 represent favorable prognostic factors for survival in AML patients. These results support the idea that cytokine deregulation may be useful as a marker for predicting clinical evolution in AML patients.

Enhanced expression of natural cytotoxicity receptors on cytokine-induced memory-like natural killer cells correlates with effector function.

Introduction: Natural killer (NK) cells are a key component of the innate immune system, involved in defending the host against virus-infected cells and tumor immunosurveillance. Under in vitro culture conditions, IL-12/15/18 can induce a memory-like phenotype in NK cells. These cytokine-induced memory-like (CIML) NK cells possess desirable characteristics for immunotherapies, including a longer lifespan and increased cytotoxicity. Methods: In this study, NK cells were isolated from peripheral blood of healthy donors and stimulated with IL-12/15/18 to induce a memory-like phenotype or with IL-15 alone as a control. After seven days of culture, multiparametric flow cytometry analysis was performed to evaluate the phenotypic and functional profiles of CIML and control NK cells. Results: Our results showed a significantly higher expression of CD25, CD69, NKG2D, NKp30, NKp44, NKp46, TACTILE, and Granzyme B in CIML NK cells compared to control NK cells. In contrast, KIR2D expression was significantly lower in CIML NK cells than in control NK cells. Moreover, functional experiments demonstrated that CIML NK cells displayed enhanced degranulation capacity and increased intracellular IFN-γ production against the target cell line K562. Interestingly, the degranulation capacity of CIML NK cells was positively correlated with the expression of the activating receptors NKp46 and NKp30, as well as with the inhibitory receptor TACTILE. Discussion: In conclusion, this study provides a deep phenotypic characterization of in vitro-expanded CIML NK cells. Moreover, the correlations found between NK cell receptors and degranulation capacity of CIML NK cells allowed the identification of several biomarkers that could be useful in clinical settings.

Spanish HCMV Seroprevalence in the 21st Century.

Human cytomegalovirus (HCMV) is linked to age-related diseases like cardiovascular disease, neurodegenerative conditions, and cancer. It can also cause congenital defects and severe illness in immunocompromised individuals. Accurate HCMV seroprevalence assessment is essential for public health planning and identifying at-risk individuals. This is the first HCMV seroprevalence study conducted in the general Spanish adult population in 30 years. We studied HCMV seroprevalence and HCMV IgG antibody titres in healthy adult donors (HDs) and HCMV-related disease patients from 2010 to 2013 and 2020 to 2023, categorized by sex and age. We compared our data with 1993 and 1999 studies in Spain. The current HCMV seroprevalence among HDs in Spain is 73.48%. In women of childbearing age, HCMV seroprevalence has increased 1.4-fold in the last decade. HCMV-seropositive individuals comprise 89.83% of CVD patients, 69% of SMI patients, and 70.37% of COVID-19 patients. No differences in HCMV seroprevalence or HCMV IgG antibody titres were observed between patients and HDs. A significant reduction in Spanish HCMV seroprevalence among HDs was observed in 1993. However, women of childbearing age have shown an upturn in the last decade that may denote a health risk in newborns and a change in HCMV seroprevalence trends.

Decreased expression of DNAM-1 on NK cells from acute myeloid leukemia patients.

This study tested the hypothesis that the expression of CD112 and CD155 (DNAM-1 ligands) on leukemic blasts induces a decreased expression of the activating receptor DNAM-1 on natural killer (NK) cells from acute myeloid leukemia (AML) patients. DNAM-1 is a co-receptor involved in the activation of NK cell cytotoxicity after its interaction with its ligands CD112 and CD155 on target cells. Here we study the expression of DNAM-1 on NK cells and DNAM-1 ligands on blasts from AML patients stratified by age. The results demonstrate that NK cells from AML patients younger than 65 years have a reduced expression of DNAM-1 compared with age-matched controls. The analysis of DNAM-1 ligands showed a high expression of CD112 and CD155 on leukemic blasts. An inverse correlation between CD112 expression on leukemic blasts and DNAM-1 expression on NK cells was found. Furthermore, downregulation of DNAM-1 was induced on healthy donors' NK cells after in vitro culture with leukemic blasts expressing DNAM-1 ligands. In conclusion, these results support the hypothesis that receptor-ligand crosslinking downregulates DNAM-1 expression on NK cells from patients <65 years of age. Considering the relevance of DNAM-1 in NK recognition and killing of leukemic cells, the reduced expression of this receptor on NK cells from AML patients can represent an additional mechanism of tumor escape.

CMV and Immunosenescence: from basics to clinics.

Alone among herpesviruses, persistent Cytomegalovirus (CMV) markedly alters the numbers and proportions of peripheral immune cells in infected-vs-uninfected people. Because the rate of CMV infection increases with age in most countries, it has been suggested that it drives or at least exacerbates "immunosenescence". This contention remains controversial and was the primary subject of the Third International Workshop on CMV & Immunosenescence which was held in Cordoba, Spain, 15-16th March, 2012. Discussions focused on several main themes including the effects of CMV on adaptive immunity and immunosenescence, characterization of CMV-specific T cells, impact of CMV infection and ageing on innate immunity, and finally, most important, the clinical implications of immunosenescence and CMV infection. Here we summarize the major findings of this workshop.

Human NK cells in acute myeloid leukaemia patients: analysis of NK cell-activating receptors and their ligands.

Natural killer (NK) cell activation is strictly regulated to ensure that healthy cells are preserved, but tumour-transformed or virus-infected cells are recognized and eliminated. To carry out this selective killing, NK cells have an ample repertoire of receptors on their surface. Signalling by inhibitory and activating receptors by interaction with their ligands will determine whether the NK cell becomes activated and kills the target cell. Here, we show reduced expression of NKp46, NKp30, DNAM-1, CD244 and CD94/NKG2C activating receptors on NK cells from acute myeloid leukaemia patients. This reduction may be induced by chronic exposure to their ligands on leukaemic blasts. The analysis of ligands for NK cell-activating receptors showed that leukaemic blasts from the majority of patients express ligands for NK cell-activating receptors. DNAM-1 ligands are frequently expressed on blasts, whereas the expression of the NKG2D ligand MICA/B is found in half of the patients and CD48, a ligand for CD244, in only one-fourth of the patients. The decreased expression of NK cell-activating receptors and/or the heterogeneous expression of ligands for major receptors on leukaemic blasts can lead to an inadequate tumour immunosurveillance by NK cells. A better knowledge of the activating receptor repertoire on NK cells and their putative ligands on blasts together with the possibility to modulate their expression will open new possibilities for the use of NK cells in immunotherapy against leukaemia.

Comparison between Histological Features and Strain Elastographic Characteristics in Canine Mammary Carcinomas.

Elastography is a sonographic technique that provides a noninvasive evaluation of the stiffness of a lesion. The objective of this work was to evaluate the accuracy of strain elastography, the most accessible modality in clinical practice, to discriminate between different histological types of malignant mammary neoplasms in the canine species, which can provide complementary information in real time to the diagnosis and thus help in the choice of surgical technique. A total of 34 females with 56 mammary carcinomas were selected and classified into three histological groups according to their aggressiveness. The histological and elastographic characteristics of these malignant tumors were analyzed and compared to evaluate the diagnostic accuracy of strain elastography. Visual score presented a sensitivity of 88.0%, specificity of 58.1%, and accuracy of 71.43% in distinguishing the most aggressive group of carcinomas. The strain ratio had a sensitivity of 84.0%, specificity of 61.1%, and accuracy of 69.64%. On the other hand, intratumoral strain ratio obtained a sensitivity of 71.40% and specificity of 61.90% when intratumoral fibrosis was taken as reference, with an accuracy of 66.07%. Similarly, peritumoral strain ratio was also positively related to fibrosis in the periphery of lesions (p ≤ 0.001), with a sensitivity of 93.80%, specificity of 77.50% and an accuracy of 92.87%. In conclusion, accuracy of this elastographic modality can be a useful method to differentiate more aggressive histological types. Therefore, it represents an additional diagnostic technique useful in the daily clinic thanks to the short time required for the examination, which allows real-time visualization and immediate interpretation of the results.

Impact of Cytomegalovirus and Age on T-Cell Subsets Defined by CD161, CD300a, and/or CD57 Expression in Healthy Andalusians.

Immunosenescence affects innate and adaptive immunity impairing the response to pathogens and vaccines. Chronic infection with cytomegalovirus (CMV) has been shown to drive "early immunosenescence" and can considerably affect both the function and phenotype of immune cells, especially T cells. We have previously shown that the expression of CD57, CD300a, and CD161 was differentially affected by age and chronic CMV infection, indicating that these markers are a hallmark of CMV infection and T-cell aging. The aim of this present study was to clarify whether these 3 markers define distinct T-cell subpopulations with a specific functional and molecular signature. Specifically, we analyzed the effect of age and chronic CMV infection on the functionality of T cells according to CD161, CD300a, and CD57 expression. We found that these markers defined different T-cell subsets, both at the phenotypic and functional levels. CD57 was the best biomarker for CD4+ T-cell cytotoxicity and was a hallmark of CMV infection. CD300a+ T cells were heterogeneous and included different cell subsets. The population of CD161+ T cells dramatically decreased with age, independently of CMV infection, and represented a sign of age-associated immune system alterations. The latter could contribute to an increased risk of autoimmune disease and infection in older adults. Our results underline the importance of better understanding the factors involved in the immunosenescence process to be able to uncover new biomarkers and open new avenues for the investigation and development of novel age-related disease therapies.

Correlation of effector function with phenotype and cell division after in vitro differentiation of naive MART-1-specific CD8+ T cells.

Adoptive transfer of antigen-specific CD8+ T cells may represent an effective strategy for immunotherapy of tumors such as melanoma, but is limited by the number and functionality of in vitro expanded T cells. Here, we document that although ELAGIGILTV-specific CD8+ T cells from different donors initially possessed a naive phenotype, after antigen-induced in vitro expansion two distinct phenotypes correlating with cell proliferation rate emerged in the different donors. Those cultures achieving fewer cumulative population doublings (CPDs) were cytotoxic and displayed a CD45RA+CCR7- phenotype. In contrast, cultures reaching higher CPDs were non-cytotoxic T cells with a CD45RA-CCR7- phenotype. Thus, the generation of larger numbers of ELAGIGILTV-specific CD8+ T cells correlates negatively with the acquisition of a CD45RA+CCR7- phenotype and cytotoxic capacity. A better understanding of the differentiation pathways of cytotoxic T cells to obtain optimally efficient cells for adoptive transfer will allow the development of new immunotherapy protocols.