Virus infection is sensed by the innate immune system through germline encoded pattern recognition receptors (PRRs). Toll-like receptors (TLRs), retinoic acid-inducible gene-I-like receptors (RLRs) and nucleotide-binding oligomerization domain-like receptors (NLRs) serve as PRRs that recognize different viral components. Microbial nucleic acids such as Ribonucleic acid (RNA) are important virus-derived pathogen-associated molecular patterns (PAMPs) to be recognized by PRRs. Virus recognition may occur at multiple stages of the viral life cycle. Replication intermediates such as single-stranded RNA (ssRNA) and double-stranded RNA (dsRNA) are detected by the RNA-sensing PRRs that initiate innate and adaptive immune responses. Triggering of the innate immune system is a critical event that can shape the adaptive immune response to virus infection. Better vaccination strategies that lead to improved T-cell and antibody responses are needed for protection against pathogens. We sought to delineate the RNA-sensing PRR pathways that are activated during infection with an RNA virus, the signaling mediators involved and the influence on subsequent virus-specific adaptive immune responses. To analyze the role of RNA-sensing PRRs in T-cell immune responses in vitro, we performed direct co-stimulation experiments on CD4+ T-cells of high purity. We utilized synthetic RNA-like immune response modifiers (IRMs) R-848 (MyD88-dependent) and poly I:C (MyD88-independent) as RNA PAMPs to determine the direct effects of RNA-sensing PRR activation on CD4+ T-cells. RNA PAMPs can act directly on CD4+ T-cells and modulate their function and phenotype. Maximal direct co-stimulatory effects were observed in CD4+ T-cells cultured with poly I:C compared to R-848. The cytoplasmic dsRNA-dependent protein kinase R (PKR) was also involved in poly I:C-mediated signaling in CD4+ T-cells. We found differences in the RNA-sensing PRRs activated by R-848 between mouse and human CD4+ T-cells. We observed minimal direct co-stimulatory effects by R-848 in mouse CD4+ T-cells. In contrast, augmentation of Th1 responses by R-848 was observed in human CD4+ T-cells. TLR8 activation in human CD4+ T-cells may explain the observed differences. We next explored the signaling pathways activated by RNA PAMPs in conventional dendritic cells (cDCs) and CD4+ T-cells that drive Th1 CD4 T-cell responses in isolated cDC/CD4 T-cell interactions. Allogeneic cDCs and CD4+ T-cells of high purity were cultured together with R-848 and poly I:C in MHC congenic mixed leukocyte reactions (MLRs). R-848 and poly I:C stimulation of type I IFN production and signaling was essential but not sufficient for driving CD4+ Th1 responses. The early production of IL-1α and IL-1β was equally critical. To analyze the role of RNA-sensing PRRs in T-cell immune responses in vivo, we utilized a mouse model of heterosubtypic influenza A virus (IAV) infections. Using MyD88-/-, TLR7-/- and IL-1-deficient mice, we explored the role of MyD88-signaling in the generation of heterosubtypic memory CD4+ T-cell, CD8+ T-cell and antibody responses. We found that MyD88 signaling played an important role in anti-IAV spleen and lung CD4+ T-cell, spleen CD8+ T-cell and Th1 antibody immune responses. Anti-IAV lung heterosubtypic CD8+ T-cell responses were not dependent on MyD88 signaling. Our in vitro and in vivo results show the pivotal role of RNA-sensing PRR pathway activation in T-cell immune responses. Understanding the complexity of the PRR pathways involved during viral infections and defining the subsequent immune response would have important implications for the generation of more effective vaccine strategies.

<p>UVOD: Glavni problem u lečenju karcinoma dojke je kako na osnovu kliničke klasifikacije i morfolo&scaron;kih osobina tumora predvideti njegovo dalje pona&scaron;anje. Vrlo često ni kombinacija standardnih prognostičkih faktora ne daje odgovor o potrebi davanja adjuvantne hemioterapije. U cilju sprovođenja adekvatne dalje terapije karcinoma dojke i otkrivanja agresivnih tipova tumora, a nakon hirur&scaron;kog lečenja, postoji stalna potreba za pronalaženjem novih pokazatelja pomoću kojih bi se identifikovale bolesnice koje imaju povećan rizik od razvoja relapsa bolesti. CILJEVI: Ciljevi su bili da se utvrdi prisustvo, lokalizacija i distribucija tumor infiltri&scaron;ućih limfocita, kako ukupnih, tako i CD4+ i CD8+ T limfocita u tumoru dojke, njihova povezanost sa standardnim prognostičkim parametrima, kao i njihov prognostički značaj tj. razlike u nivou infiltracije limfocita u tumoru u odnosu na pojavu relapsa bolesti i dužinu preživljavanja. METOD: Istraživanjem je obuhvaćeno 120 bolesnica sa invazivnim duktalnim karcinomom, sa tumorom lokalizovanim samo u dojci, bez zahvatanja kože i grudnog mi&scaron;ića, sa veličinom tumora do 5 cm, bez udaljenih visceralnih i ko&scaron;tanih metastaza, koje su operisane u Institutu za onkologiju Vojvodine. U istraživanje su uključene bolesnice bez metastaza u limfnim čvorovima pazu&scaron;ne jame i bolesnice sa metastazama u limfnim čvorovima pazu&scaron;ne jame. Istraživanjem nisu obuhvaćene bolesnice koje su primale neoadjuvantnu (preoperativnu) hemioterapiju, kao ni bolesnice sa multifokalnim i multicentričnim tumorima. REZULTATI: Gust limfocitni infiltrat uočen je u 14% tumora dojke, umeren limfocitni infiltrat uočen je u 38%, a oskudan u 43% tumora dojke. Limfocitni infiltrat nije uočen u 5% tumora. Gust infiltrat CD4+ limfocita uočen je u 8% tumora dojke, umeren u 44%, a oskudan u 43% tumora dojke. CD4+ limfociti nisu uočeni u 5% tumora. Gust infiltrat CD8+ limfocita uočen je u 1% tumora dojke, umeren u 23%, a oskudan u 66% tumora dojke. CD8+ limfociti nisu uočeni u 10% tumora. Utvrđena je pozitivna povezanost između nivoa TIL-a i CD4+ limfocita i veličine tumora, histolo&scaron;kog stepena diferentovanosti tumora, prisustva metastaza u limfnim čvorovima pazu&scaron;ne jame, HER-2 statusa, tripl negativnog tumora i relapsa bolesti. Utvrđena je negativna povezanost između nivoa TIL-a i CD4+ limfocita i estrogen i progesteron receptora, kao i godina starosti. Utvrđena je pozitivna povezanost između nivoa CD8+ limfocita i histolo&scaron;kog gradusa tumora, kao i HER-2 statusa. Utvrđena je negativna povezanost između nivoa CD8+ limfocita i estrogen i progesteron receptora, kao i godina starosti. ZAKLJUČAK:Rezultati ovog istraživanja pokazuju povezanost tumor infiltri&scaron;ućih limfocita i CD4+ limfocita sa brojnim negativnim prognostičkim faktorima, te kraćim vremenom slobodnog intervala bez bolesti, &scaron;to sve ukazuje na to da su tumor infiltri&scaron;ući limfociti kao i CD4+ limfociti lo&scaron; prognostički faktor kod bolesnica sa rakom dojke.</p> / <p>INTRODUCTION: The main problem in the treatment of breast cancer that based on clinical classification and morphological characteristics of the tumor to predict its future behavior. Very often, not a combination of standard prognostic factors does not answer the need of giving adjuvant chemotherapy. In order to implement adequate further treatment of breast cancer and detection aggressive types of tumor, after surgical treatment, there is a constant need to find new indicators by which we can identify patients who have an increased risk of relapse. OBJECTIVES: The objectives were to determine the presence, localization and distribution of tumor infiltrating lymphocytes, in total, as well as CD4+ and CD8+ T lymphocytes in breast cancer, their correlation with standard prognostic parameters, as well as their prognostic value i.e. differences in the level of infiltration of lymphocytes in a tumor in relation to the occurrence of disease relapse and survival. METHOD: The study included 120 patients with invasive ductal carcinoma, tumor localized only in the breast without involvement of the skin and pectoral muscle, the size of tumors up to 5 cm without distant visceral and bone metastases, which are operated at the Institute of Oncology. The study included patients without metastases in axillary lymph nodes and patients with metastases in axillary lymph nodes. The research not covered by patients receiving neoadjuvant chemotherapy, or patients with multifocal and multicentric tumors. RESULTS: The high amount of lymphocytic infiltrate was observed in the 14% a breast tumor, a moderate amount of lymphocytic infiltrate was observed in 38%, and the low in 43% breast tumors. Lymphocytic infiltrate was not observed in 5% of the tumor. High CD4+ lymphocyte infiltration was observed in 8% of breast, moderate in 44%, and the low in 43% of breast tumors. CD4+ lymphocytes were not observed in 5% tumors. High infiltration of CD8+ lymphocytes was observed in 1% of breast, moderate in 23%, and the low 66% breast tumors. CD8+ lymphocytes have not been observed in 10% tumors. There is a positive correlation between the level of TIL and CD4+ lymphocytes and tumor size, histological grade of tumor differentiation, presence of metastases in axillary lymph nodes, HER-2 status, triple negative tumors and relapses of disease. There was a negative correlation between the level of TIL and CD4+ cell counts and estrogen and progesterone receptors, as well as age. There is a positive correlation between the level of CD8+ cells and histological grade of the tumor, and HER-2 status. There was a negative correlation between the level of CD8+ lymphocytes and estrogen and progesterone receptors, as well as age. CONCLUSION: The results of this study demonstrate the association between tumor infiltrating lymphocytes and CD4+ lymphocytes with a number of negative prognostic factors, and shorter free interval without the disease, all of which indicates that the tumor infiltrating lymphocytes and CD4+ lymphocytes bad prognostic factor in patients with breast cancer.</p>

OBJECTIVES: The integrin α4β7 is the gut-homing receptor for lymphocytes. It also is an important co-receptor for human immunodeficiency virus (HIV) via glycoprotein (gp)120 binding. Depletion of gut cluster of differentiation (CD)4 T cells is linked to chronic inflammation in patients with HIV; however, measuring CD4 cells in the gut is invasive and not routine. As such, establishing a peripheral marker for CD4 depletion of the gut is needed. We hypothesized that α4β7 CD4 T cells are depleted in the peripheral blood of treatment-naïve patients with HIV compared with healthy controls. METHODS: The study groups were treatment-naïve patients with HIV and uninfected controls. Subjects were included if they were 18 years or older with no history of opportunistic infections, active tuberculosis, or cancer. We collected peripheral blood and examined on whole blood using flow cytometry for the following cell surface markers: CD4, CD45RO, chemokine receptor type 5, C-X-C chemokine receptor type 4 (CXCR4), and the integrin β7. We collected demographic information, including age, sex, and ethnicity, as well as viral load (VL) and CD4 count. Two-samplettests and Fisher exact tests were used to compare the differences between the two groups. Spearman correlation coefficients were calculated between CD4 count and log10-VL and percentage of CD4+/CD45RO+/β7+and log10-VL in patients. RESULTS: Twenty-two subjects were enrolled in the study (12 patients with HIV and 10 controls). There were no differences in age or sex between the two groups. There were more Hispanics and fewer Asians in the group comprising patients with HIV compared with the control group (7 vs 2 and 0 vs 4,P= 0.05, respectively). Patients infected with HIV had significantly lower frequencies of CD4+/CD45RO+/β7+cells (median 12%, range 5-18 compared with uninfected controls: median 20%, range 11-26,P= 0.0007). There was a statistically significant difference in the percentage of CD4+/CD45RO+/C-X-C chemokine receptor type 4+cells between patients (72%, range 60%-91%) compared with controls (79%, range 72%-94%,P= 0.04). The percentage of CD4+/CD45RO+/chemokine receptor type 5+did not differ between the group of patients with HIV and the control groups (22%, range 11%-57% vs 27%, range 14%-31%;P= 0.8, respectively). There was no correlation between percentage of CD4+/CD45RO+/β+cells and log10-VL as measured by the Spearman correlation coefficient (r= 0.05,P= 0.88) in patients infected with HIV. CONCLUSIONS: Memory CD4 β7+cells are reduced significantly in the peripheral blood of untreated patients infected with HIV, which could be used as a noninvasive indicator of intestinal CD4 T cell loss and recovery. Further studies are needed to examine whether depletion of these CD4+/CD45RO+/β7+cells in the peripheral blood parallels depletion in the gut of treatment-naïve patients with HIV and whether levels return to control levels after treatment.

Abordagens atuais no desenho de vacinas contra o HIV-1 estão focadas em imunógenos que codificam proteínas inteiras do HIV-1 e visam induzir respostas citotóxicas específicas. É concebível que vacinas bem-sucedidas devem induzir respostas contra múltiplos epitopos do HIV-1, coincidindo com seqüências das cepas circulantes do vírus, conhecido por sua grande variabilidade genética. Sabe-se que células T CD4+ são necessárias para indução de respostas efetivas de linfócitos T CD8+ citotóxicos. Neste trabalho, nós avaliamos a imunogenicidade de uma vacina de DNA codificando 18 epitopos para linfócitos T CD4+, conservados e ligadores de múltiplas moléculas HLA-DR em camundongos BALB/c e em quatro linhagens de camundongos transgênicos para moléculas de HLA classe II. Os camundongos imunizados apresentaram respostas de amplitude e magnitude significativas com proliferação e secreção de citocinas por linfócitos T CD4+ e T CD8+. Onze dos 18 epitopos para linfócitos T CD4+ presentes na vacina foram reconhecidos pelas linhagens de camundongos transgênicos para moléculas de HLA classe II. Em suma, 17 dos 18 epitopos codificados pela vacina foram reconhecidos. As células induzidas pela vacina apresentaram um perfil polifuncional com tipo 1 de citocinas, incluindo produção de IFN- , TNF- e IL-2. A vacina também induziu células T CD4+ de memória central de longa duração, capazes de fornecer auxílio contínuo para células T CD8 +. Pela capacidade da vacina HIVBr18 de induzir respostas contra múltiplos epitopos de linfócitos T CD4+ conservados que podem ser reconhecidos no contexto de múltiplas moléculas de HLA classe II, esse conceito vacinal pode solucionar o problema da variabilidade genética viral assim como aumentar a cobertura populacional. Portanto, essa vacina, pode ser útil se utilizada isoladamente ou como fonte de auxílio cognato para células T CD8+ HIV-específicas induzidas por outros imunógenos gerando resposta em uma grande proporção dos vacinados / Current HIV vaccine approaches are focused on immunogens encoding whole HIV antigenic proteins that elicit cytotoxic CD8+ responses. It is conceivable that successful vaccines have to elicit responses to multiple epitopes, to match circulating strains of HIV, a virus known for its high genetic variability. It is known that CD4+ T cell responses are necessary for effective CD8+ antiviral responses. Here we assessed the immunogenicity of a DNA vaccine encoding 18 conserved, multiple HLA-DR-binding HIV CD4 epitopes in BALB/c and four strains of HLA class II-transgenic mice. Immunized mice displayed CD4+ and CD8+ proliferative and cytokine T cell responses of significant breadth and magnitude. Eleven out of the 18 encoded epitopes were recognized by CD4+ T cells from HLA class IItransgenic strain. Overall, 17 out of the 18 encoded peptides were recognized. The induced T cell response had a polyfunctional type 1 cytokine profile, including IFN- , TNF- and IL-2. The vaccine also induced long-lived central memory CD4+ T cells, which might provide sustained help for CD8+ T cells. By virtue of inducing broad responses against conserved CD4+ T cell epitopes that can be recognized in the context of widely diverse, common HLA class II alleles, this vaccine concept may cope both with HIV genetic variability and increased population coverage. The vaccine may thus be usefull either as a standalone approach or as a source of cognate help for HIV-specific CD8+ T cells elicited by conventional immunogens, eliciting responses in a wide proportion of vaccinees

The prevalence of diabetes is approaching epidemic proportions worldwide. There is currently no cure for type 1 diabetes, and successful treatment requires constant monitoring of blood sugars and use of exogenous insulin to prevent hyperglycemia. Diabetes will be curable when pancreatic β-islet cells can be transplanted into diabetes patients without requiring long-term immunosuppression. This will require learning more about the induction of functional tolerance, a state that maintains the competence of the immune system to most antigens but protects graft-specific antigens from immune rejection, permitting transplantation. One known mechanism of peripheral tolerance is T cell anergy, a phenotype of hypo-reponsiveness in CD4+ T cells. The focus of this thesis is a description of factors shown to be specific to the induction and maintenance of T cell anergy, whose loss reverses the anergic phenotype, restoring the ability of the cells to proliferate in response to antigen. The first of these is Egr-2, a zinc-finger transcription factor, whose presence is required for the induction of anergy induced in T cell clones by TCR stimulation in the absence of costimulation. Egr-2 is shown to be important to anergy induction but not anergy maintenance. In contrast, a negative costimulation receptor, PD-1, is shown to be necessary for the maintenance of anergy. It is possible that learning more about the genetic factors that orchestrate T cell anergy will prove useful in the development of tolerance-based protocols for organ and tissue transplantation without the use of long-term immunosuppression.

Abordagens atuais no desenho de vacinas contra o HIV-1 estão focadas em imunógenos que codificam proteínas inteiras do HIV-1 e visam induzir respostas citotóxicas específicas. É concebível que vacinas bem-sucedidas devem induzir respostas contra múltiplos epitopos do HIV-1, coincidindo com seqüências das cepas circulantes do vírus, conhecido por sua grande variabilidade genética. Sabe-se que células T CD4+ são necessárias para indução de respostas efetivas de linfócitos T CD8+ citotóxicos. Neste trabalho, nós avaliamos a imunogenicidade de uma vacina de DNA codificando 18 epitopos para linfócitos T CD4+, conservados e ligadores de múltiplas moléculas HLA-DR em camundongos BALB/c e em quatro linhagens de camundongos transgênicos para moléculas de HLA classe II. Os camundongos imunizados apresentaram respostas de amplitude e magnitude significativas com proliferação e secreção de citocinas por linfócitos T CD4+ e T CD8+. Onze dos 18 epitopos para linfócitos T CD4+ presentes na vacina foram reconhecidos pelas linhagens de camundongos transgênicos para moléculas de HLA classe II. Em suma, 17 dos 18 epitopos codificados pela vacina foram reconhecidos. As células induzidas pela vacina apresentaram um perfil polifuncional com tipo 1 de citocinas, incluindo produção de IFN- , TNF- e IL-2. A vacina também induziu células T CD4+ de memória central de longa duração, capazes de fornecer auxílio contínuo para células T CD8 +. Pela capacidade da vacina HIVBr18 de induzir respostas contra múltiplos epitopos de linfócitos T CD4+ conservados que podem ser reconhecidos no contexto de múltiplas moléculas de HLA classe II, esse conceito vacinal pode solucionar o problema da variabilidade genética viral assim como aumentar a cobertura populacional. Portanto, essa vacina, pode ser útil se utilizada isoladamente ou como fonte de auxílio cognato para células T CD8+ HIV-específicas induzidas por outros imunógenos gerando resposta em uma grande proporção dos vacinados / Current HIV vaccine approaches are focused on immunogens encoding whole HIV antigenic proteins that elicit cytotoxic CD8+ responses. It is conceivable that successful vaccines have to elicit responses to multiple epitopes, to match circulating strains of HIV, a virus known for its high genetic variability. It is known that CD4+ T cell responses are necessary for effective CD8+ antiviral responses. Here we assessed the immunogenicity of a DNA vaccine encoding 18 conserved, multiple HLA-DR-binding HIV CD4 epitopes in BALB/c and four strains of HLA class II-transgenic mice. Immunized mice displayed CD4+ and CD8+ proliferative and cytokine T cell responses of significant breadth and magnitude. Eleven out of the 18 encoded epitopes were recognized by CD4+ T cells from HLA class IItransgenic strain. Overall, 17 out of the 18 encoded peptides were recognized. The induced T cell response had a polyfunctional type 1 cytokine profile, including IFN- , TNF- and IL-2. The vaccine also induced long-lived central memory CD4+ T cells, which might provide sustained help for CD8+ T cells. By virtue of inducing broad responses against conserved CD4+ T cell epitopes that can be recognized in the context of widely diverse, common HLA class II alleles, this vaccine concept may cope both with HIV genetic variability and increased population coverage. The vaccine may thus be usefull either as a standalone approach or as a source of cognate help for HIV-specific CD8+ T cells elicited by conventional immunogens, eliciting responses in a wide proportion of vaccinees

We have previously shown that chronic Hepatitis C virus (HCV) infection can induce DNA damage and immune dysfunctions with excessive oxidative stress in T cells. Furthermore, evidence suggests that HCV contributes to increased susceptibility to metabolic disorders. However, the underlying mechanisms by which HCV infection impairs cellular metabolism in CD4 T cells remain unclear. In this study, we evaluated mitochondrial mass and intracellular and mitochondrial reactive oxygen species (ROS) production by flow cytometry, mitochondrial DNA (mtDNA) content by real-time qPCR, cellular respiration by seahorse analyzer, and dysregulated mitochondrial-localized proteins by Liquid Chromatography-Mass Spectrometry (LC-MS) in CD4 T cells from chronic HCV-infected individuals and health subjects. Mitochondrial mass was decreased while intracellular and mitochondrial ROS were increased, expressions of master mitochondrial regulators peroxisome proliferator-activated receptor 1 alpha (PGC-1α) and mitochondrial transcription factor A (mtTFA) were down-regulated, and oxidative stress was increased while mitochondrial DNA copy numbers were reduced. Importantly, CRISPR/Cas9-mediated knockdown of mtTFA impaired cellular respiration and reduced mtDNA copy number. Furthermore, proteins responsible for mediating oxidative stress, apoptosis, and mtDNA maintenance were significantly altered in HCV-CD4 T cells. These results indicate that mitochondrial functions are compromised in HCV-CD4 T cells, likely the deregulation of several mitochondrial regulatory proteins.

We studied the effects of 30 minutes of exercise on T lymphocyte counts and proliferative responses of peripheral blood mononuclear cells (PBMC) in 25 runners. Exercise resulted in a T lymphocytosis in the immediate post-exercise period in all subjects (p < 0.001), and reduced CD4+/CD8+ ratios in 22/25 subjects (p = 0.001). The change was due primarily to a 2.2-fold increase in CD8+ cells (p < 0.001). Exercise also reduced PBMC mitogenic responses to phytohemagglutinin (PHA) in 13/14 subjects (p = 0.049), and to pokeweed mitogen (PWM) in 11/14 subjects (p = 0.022), but not to concanavalin A. Postrun sera from 5 of 6 subjects inhibited PHA but not PWM responses of resting autologous PBMC with normal CD4+/CD8+ ratios (p < or = 0.05): indomethacin and monocyte depletion blocked the serum inhibition (p = 0.003, p = 0.0006, respectively). We conclude that post-exercise suppression of mitogenic responses to PHA is due to the release of a serum factor(s) capable of inducing prostaglandin synthesis by circulating monocytes, whereas exercise-induced suppression of PWM responses depends primarily on the reversal of CD4+/CD8+ ratios.