Distinct CD4-CD8- (Double-Negative) Memory T-Cell Subpopulations Are Associated With Indeterminate and Cardiac Clinical Forms of Chagas Disease.

CD4-CD8- (double-negative, DN) T cells are critical orchestrators of the cytokine network associated with the pathogenic inflammatory response in one of the deadliest cardiomyopathies known, Chagas heart disease, which is caused by Trypanosoma cruzi infection. Here, studying the distribution, activation status, and cytokine expression of memory DN T-cell subpopulations in Chagas disease patients without cardiac involvement (indeterminate form-IND) or with Chagas cardiomyopathy (CARD), we report that while IND patients displayed a higher frequency of central memory, CARD had a high frequency of effector memory DN T cells. In addition, central memory DN T cells from IND displayed a balanced cytokine profile, characterized by the concomitant expression of IFN-γ and IL-10, which was not observed in effector memory DN T cells from CARD. Supporting potential clinical relevance, we found that the frequency of central memory DN T cells was associated with indicators of better ventricular function, while the frequency of effector memory DN T cells was not. Importantly, decreasing CD1d-mediated activation of DN T cells led to an increase in IL-10 expression by effector memory DN T cells from CARD, restoring a balanced profile similar to that observed in the protective central memory DN T cells. Targeting the activation of effector memory DN T cells may emerge as a strategy to control inflammation in Chagas cardiomyopathy and potentially in other inflammatory diseases where these cells play a key role.

A high CD8 to FOXP3 ratio in the tumor stroma and expression of PTEN in tumor cells are associated with improved survival in non-metastatic triple-negative breast carcinoma.

BACKGROUND: Triple-negative mammary carcinoma (TNBC) is an aggressive breast cancer subtype associated with dismal prognosis. The interaction between the immune system and the cancer cells plays a crucial role in tumor development and progression. However, it is still unclear how each diverse cell of the immune system contributes to the prognosis of patients with breast cancer. In this study, we investigated how the cell composition of the immune cell infiltrated modifies the survival of patients with resected TNBC. METHODS: Retrospectively, we collected data from 76 patients diagnosed with non-metastatic TNBC with available tissue blocks for tissue micro-array (TMA) construction. The TMA was constructed using two cores from each tumor block. The expression of CD4, CD8, FOXP3, CD20, CD68, CD163, PD-1, PD-L1, PTEN and phospho-STAT1 was determined by immunohistochemistry. RESULTS: We observed that the inflammatory infiltrate in TNBC is enriched for M2 macrophages and T lymphocytes (CD4+, CD8+). PD-L1 expression in the stroma was associated with the percentage of TILs (p = 0.018) as, PD-L1 expression in the tumor was associated with the percentage of TILs (p = 0.049). We found a correlation between TILs and PD-L1 expression in stroma cells (p = 0.020) and in tumor cells (p = 0.027). In our cohort, we observed a trend for improved survival associated with higher CD8+ (p = 0.054) and CD4 + (p = 0.082) cell counts, but the results were not statistically significant. Conversely, the expression of PTEN in tumor cells and a low number of FOXP3+ cells in tumor stroma were both associated with improved OS. The CD8 to FOXP3 ratio and the CD4 to FOXP3 ratio were associated with better OS as well, however, only the CD8 to FOXP3 ratio had its prognostic impact confirmed in the METABRIC TNBC cohort. There was no association between PD-L1 expression and OS. CONCLUSION: TNBC tumor microenvironment is enriched for lymphocytes and macrophages. FOXP3 expression and the CD8 to FOXP3 ratio in the tumor stroma as well as the loss of PTEN expression in tumor cells are prognostic factors in non-metastatic TNBC.

Fas/FasL Signaling Regulates CD8 Expression During Exposure to Self-Antigens.

Activation of self-reactive CD8+ T cells induces a peripheral tolerance mechanism that involves loss of CD8 expression. Because genetic deficiency of Fas and Fasl causes the accumulation of double-negative (DN; CD3+ TCR-αß+ CD4- CD8-) T cells that have been proposed to derive from CD8+ cells, we decided to explore the role of Fas and FasL in self-antigen-induced CD8 downregulation. To this end, we quantified Fas and FasL induction by different stimuli and analyzed the effects of Fas/FasL deficiency during a protective immune response and after exposure to self-antigens. Our data describes how Fas and FasL upregulation differs depending on the setting of CD8 T cell activation and demonstrates that Fas/FasL signaling maintains CD8 expression during repetitive antigen stimulation and following self-antigen encounter. Together, our results reveal an unexpected role of Fas/FasL signaling and offer a new insight into the role of these molecules in the regulation of immune tolerance.

Hypoxia-mediated down-regulation of miRNAs' biogenesis promotes tumor immune escape in bladder cancer.

BACKGROUND: The study examines the function of hypoxia-mediated down-regulation of microRNAs (miRNAs) (mir-30c, mir-135a, and mir-27a) in the process of bladder cancer immune escape. METHODS: Quantitative Real-time PCR (qRT-PCR) was carried out to determine gene expression levels of Drosha and Dicer under hypoxia treatment, while western blotting and flow cytometry were used to determine protein expression. Seven reported miRNAs were identified via qRT-PCR assay. Flow cytometry detection of CD3/CD4/CD8-positive expression and statistics. Enzyme-linked immunosorbent assay (ELISA) detected cellular immune factors content. Cell apoptosis was checked via flow cytometry assay. Luciferase report assay and western blot assays were both used to verify the relationship between miRNAs and Casitas B-lineage lymphoma proto-oncogene b (Cbl-b). The animal model was established and Hematoxylin-eosin (HE) staining, TdT-mediated dUTP Nick-End Labeling (TUNEL) staining, and immunohistochemistry (IHC) assays were separately used to verify the conclusions. RESULTS: The CD3 + /CD4 + expression was increased in the hypoxia group, while CD3 + /CD8 + expression, the cellular immune factors content Interleukin-2 (IL-2) and Tumor Necrosis Factor-α (TNFα) along with the cell apoptosis were suppressed. The protein expression of Cbl-b was found to be up-regulated in the hypoxia group. After constructing the overexpression/ knockdown of Cbl-b in peripheral blood mononuclear cell (PBMC), Cbl-b has been found to promote tumor immune escape in bladder cancer. Furthermore, Cbl-b had been identified as the co-targets of mir-30c, mir-135a, and mir-27a and down-regulation of miRNA biogenesis promotes Cbl-b expression and deactivating T cells in vitro/in vivo. CONCLUSION: Hypoxia-mediated down-regulation of miRNAs' biogenesis promotes tumor immune escape in bladder cancer, which could bring much more advance to the medical research on tumors.

Percentages of CD4+CD8+ Double-positive T Lymphocytes in the Peripheral Blood of Adults from a Blood Bank in Bogotá, Colombia

Objective: CD4+CD8+ double-positive T-cells (DPTs) have been classified as a separate T-cell subpopulation, with two main phenotypes: CD4high CD8low and CD4low CD8high. In recent years, the relevance of DPTs in the pathogenesis of infections, tumors, and autoimmune diseases has been recognized. Reference values among healthy individuals remain unknown. Therefore, the aim of this study is to provide a reference value for DPTs in peripheral blood from healthy donors in a blood bank in Bogotá, Colombia, and to determine the activation status using a surface marker. Materials and Methods: One hundred healthy donors were enrolled in the study. Peripheral blood cells were stained for CD3, CD4, CD8, and CD154 (CD40L), and cellular viability was assessed with 7-aminoactinomycin D and analyzed by flow cytometry. Results: The median value for DPTs was 2.6% (interquartile range=1.70%-3.67%). Women had higher percentages of DPTs than men (3.3% vs. 2.1%). The subpopulation of CD4low CD8high showed higher expression of CD154 than the other T-cell subpopulations. Conclusion: DPT reference values were obtained from blood bank donors. A sex difference was found, and the CD4low CD8high subpopulation had the highest activation marker expression.

The Vacuolar Pathway in Macrophages Plays a Major Role in Antigen Cross-Presentation Induced by the Pore-Forming Protein Sticholysin II Encapsulated Into Liposomes.

Cross-presentation is an important mechanism for the differentiation of effector cytotoxic T lymphocytes (CTL) from naïve CD8+ T-cells, a key response for the clearance of intracellular pathogens and tumors. The liposomal co-encapsulation of the pore-forming protein sticholysin II (StII) with ovalbumin (OVA) (Lp/OVA/StII) induces a powerful OVA-specific CTL activation and an anti-tumor response in vivo. However, the pathway through which the StII contained in this preparation is able to induce antigen cross-presentation and the type of professional antigen presenting cells (APCs) involved have not been elucidated. Here, the ability of mouse bone marrow-derived dendritic cells (BM-DCs) and macrophages (BM-MΦs) stimulated with Lp/OVA/StII to activate SIINFEKL-specific B3Z CD8+ T cells was evaluated in the presence of selected inhibitors. BM-MΦs, but not BM-DCs were able to induce SIINFEKL-specific B3Z CD8+ T cell activation upon stimulation with Lp/OVA/StII. The cross-presentation of OVA was markedly decreased by the lysosome protease inhibitors, leupeptin and cathepsin general inhibitor, while it was unaffected by the proteasome inhibitor epoxomicin. This process was also significantly reduced by phagocytosis and Golgi apparatus function inhibitors, cytochalasin D and brefeldin A, respectively. These results are consistent with the concept that BM-MΦs internalize these liposomes through a phagocytic mechanism resulting in the cross-presentation of the encapsulated OVA by the vacuolar pathway. The contribution of macrophages to the CTL response induced by Lp/OVA/StII in vivo was determined by depleting macrophages with clodronate-containing liposomes. CTL induction was almost completely abrogated in mice depleted of macrophages, demonstrating the relevance of these APCs in the antigen cross-presentation induced by this formulation.

Skewed Invariant Natural Killer T (iNKT) Cells, Impaired iNKT:B Cell Help and Decreased SAP Expression in Blood Lymphocytes from Patients with Common Variable Immunodeficiency.

Common variable immunodeficiency (CVID) is a syndrome with predominantly defective B cell function. However, abnormalities in the number and function of other lymphocyte subpopulations in peripheral blood (PB) have been described in most patients. We have analysed the distribution of iNKT cell subpopulations in the PB of CVID patients and the ability of these cells to provide in vitro cognate B cell help. The total of iNKT cells was reduced in the PB of CVID patients, especially CD4+, CD4-/CD8- and CCR5+/CXCR3+. These findings were associated with an enrichment of memory-like and a tendency towards a reduction in TNF-α-expressing effector iNKT cells in the peripheral blood mononuclear cells (PBMC) of CVID patients. Moreover, an accumulation of follicular helper iNKT cells in the PB of CVID patients was demonstrated. CVID αGalCer-pulsed iNKT cells are not able to induce autologous B cell proliferation although they do induce proliferation to healthy donor B cells. Interestingly, autologous and heterologous co-cultures did not differ in the amount of immunoglobulin secreted by B cells in vitro. Finally, reduced intracellular SAP expression in iNKT cells and other lymphocytes in the blood from CVID patients was observed. These results provide further insights into the immunological mechanisms underlying the iNKT cell defects and the potential targets to improve B cell help in CVID.

Specific activation of CD4- CD8- double-negative T cells by Trypanosoma cruzi-derived glycolipids induces a proinflammatory profile associated with cardiomyopathy in Chagas patients.

Cardiomyopathy is the most severe outcome of Chagas disease, causing more than 12 000 deaths/year. Immune cells participate in cardiomyopathy development either by direct tissue destruction, or by driving inflammation. We have shown that CD4- CD8- [double-negative (DN)] T cells are major sources of inflammatory and anti-inflammatory cytokines, associated with the cardiac (CARD) and indeterminate (IND) forms of Chagas disease, respectively. Here, we sought to identify Trypanosoma cruzi-derived components that lead to activation of DN T cells in Chagas patients. Glycolipid (GCL), lipid (LIP) and protein-enriched (PRO) fractions derived from trypomastigote forms of T. cruzi were utilized to stimulate cells from IND and CARD patients to determine DN T cell activation by evaluating CD69 and cytokine expression. We observed that GCL, but not LIP or PRO fractions, induced higher activation of DN T cells, especially T cell receptor (TCR)-γδ DN T, from IND and CARD. GCL led to an increase in tumour necrosis factor (TNF) and interleukin (IL)-10 expression by TCR-γδ DN T cells from IND, while inducing IFN-γ expression by TCR-γδ DN T cells from CARD. This led to an increase in the ratio IFN-γ/IL-10 in TCR-γδ DN T cells from CARD, favouring an inflammatory profile. These results identify GCL as the major T. cruzi component responsible for activation of DN T cells in chronic Chagas disease, associated predominantly with an inflammatory profile in CARD, but not IND. These findings may have implications for designing new strategies of control or prevention of Chagas disease cardiomyopathy by modulating the response to GCL.

Focal myositis presenting as pseudothrombophlebitis of the arm.

We described a 21-year-old woman with a diagnosis of Sjögren syndrome that came for consultation with a localized mass over her left arm of fast growth. Lab results were normal; a Doppler ultrasound showed the presence of partial thrombosis in the left axillary vein; a magnetic resonance imaging showed edema on the biceps muscle and the biopsy of the mass disclosed the presence of severe lymphocyte infiltrate within the connective tissue and scarce muscle fibers. Immunostaining showed positive results for antígeno comun leucocitario in spanish (leukocyte common antigen) (ACL) and CD3. Those results are consistent with the diagnosis of focal myositis. The patient was treated with low doses of prednisone and methotrexate, with good response.

Increased NY-ESO-1 expression and reduced infiltrating CD3+ T cells in cutaneous melanoma.

NY-ESO-1 is a cancer-testis antigen aberrantly expressed in melanomas, which may serve as a robust and specific target in immunotherapy. NY-ESO-1 antigen expression, tumor features, and the immune profile of tumor infiltrating lymphocytes were assessed in primary cutaneous melanoma. NY-ESO-1 protein was detected in 20% of invasive melanomas (16/79), rarely in in situ melanoma (1/10) and not in benign nevi (0/20). Marked intratumoral heterogeneity of NY-ESO-1 protein expression was observed. NY-ESO-1 expression was associated with increased primary tumor thickness (P = 0.007) and inversely correlated with superficial spreading melanoma (P < 0.02). NY-ESO-1 expression was also associated with reduced numbers and density of CD3+ tumor infiltrating lymphocytes (P = 0.017). When NY-ESO-1 protein was expressed, CD3+ T cells were less diffusely infiltrating the tumor and were more often arranged in small clusters (P = 0.010) or as isolated cells (P = 0.002) than in large clusters of more than five lymphocytes. No correlation of NY-ESO-1 expression with gender, age, tumor site, ulceration, lymph node sentinel status, or survival was observed. NY-ESO-1 expression in melanoma was associated with tumor progression, including increased tumor thickness, and with reduced tumor infiltrating lymphocytes.

CD8+ TIL recruitment may revert the association of MAGE A3 with aggressive features in thyroid tumors.

BACKGROUND: We aimed to investigate a possible role of MAGE A3 and its associations with infiltrated immune cells in thyroid malignancy, analyzing their utility as a diagnostic and prognostic marker. MATERIALS AND METHODS: We studied 195 malignant tissues: 154 PTCs and 41 FTCs; 102 benign tissues: 51 follicular adenomas and 51 goiter and 17 normal thyroid tissues. MAGE A3 and immune cell markers (CD4 and CD8) were evaluated using immunohistochemistry and compared with clinical pathological features. RESULTS: The semiquantitative analysis and ACIS III analysis showed similar results. MAGE A3 was expressed in more malignant than in benign lesions (P < 0.0001), also helping to discriminate follicular-patterned lesions. It was also higher in tumors in which there was extrathyroidal invasion (P = 0.0206) and in patients with stage II disease (P = 0.0107). MAGE A3+ tumors were more likely to present CD8+ TIL (P = 0.0346), and these tumors were associated with less aggressive features, that is, extrathyroidal invasion and small size. There was a trend of MAGE A3+ CD8+ tumors to evolve free of disease. CONCLUSION: We demonstrated that MAGE A3 and CD8+ TIL infiltration may play an important role in malignant thyroid nodules, presenting an interesting perspective for new researches on DTC immunotherapy.

Role of angiotensin II in the brain inflammatory events during experimental diabetes in rats.

Hyperglycemia during diabetes is one of the causes of encephalopathy. However, diabetes causes chronic inflammatory complications and among them is peripheral neuropathy. Since, diabetes is one of the major risk factors for cerebrovascular disease, inflammatory process could take place in central nervous system (CNS). To test that hypothesis, experiments to determine inflammatory events in CNS during streptozotocin-induced diabetes were performed. Diabetes was induced by intravenous injection of streptozotocin (STZ). Brain angiotensin II (Ang II), monocyte/macrophage (ED-1 positive cells), CD8, the intercellular adhesion molecule-1 (ICAM-1), the lymphocyte function-associated antigen-1 (LFA-1) and superoxide anion were determined by hystochemical and immunohistochemical methods. Nitric oxide (NO), malondialdehyde (MDA) and catalase activity were measured in brain homogenates by enzymatic and biochemical methods. This research showed increased expressions of Ang II, ICAM-1, LFA-1 and CD8 positive cells in diverse zones of cerebrum and cerebellum of diabetic rats (week 8). Treatment of diabetic animals with losartan or enalapril reduced the expression of those molecules. Values of lipid peroxidation, nitrite content and superoxide anion expression remained similar to control rats. Only decreased activity of catalase was observed in diabetic animals, but losartan or enalapril failed to modify catalase activity. This study suggests the presence of Ang II-mediated brain inflammatory events in diabetes probably mediated by AT1 receptors.

Purified herpes simplex type 1 glycoprotein D (gD) genetically fused with the type 16 human papillomavirus E7 oncoprotein enhances antigen-specific CD8+ T cell responses and confers protective antitumor immunity.

Type 1 herpes virus (HSV-1) glycoprotein D (gD) enhances antigen-specific immune responses, particularly CD8(+) T cell responses, in mice immunized with DNA vaccines encoding hybrid proteins genetically fused with the target antigen at a site near the C-terminal end. These effects are attributed to the interaction of gD with the herpes virus entry mediator (HVEM) and the concomitant blockade of a coinhibitory mechanism mediated by the B- and T-lymphocyte attenuator (BTLA). However, questions concerning the requirement for endogenous synthesis of the antigen or the adjuvant/antigen fusion itself have not been addressed so far. In the present study, we investigated these points using purified recombinant gDs, genetically fused or not with type 16 papilloma virus (HPV-16) E7 oncoprotein. Soluble recombinant gDs, but not denatured forms, retained the ability to bind surface-exposed cellular receptors of HVEM-expressing U937 cells. In addition, in vivo administration of the recombinant proteins, particularly gD genetically fused with E7 (gDE7), promoted the activation of dendritic cells (DC) and antigen-specific cytotoxic CD8(+) T cells. More relevantly, mice immunized with the gDE7 protein developed complete preventive and partial therapeutic antitumor protection, as measured in mice following the implantation of TC-1 cells expressing HPV-16 oncoproteins. Collectively, these results demonstrate that the T cell adjuvant effects of the HSV-1 gD protein did not require endogenous synthesis and could be demonstrated in mice immunized with purified recombinant proteins.

Altered phenotype and functionality of circulating immune cells characterize adult patients with nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is a chronic inflammatory liver disease associated with insulin resistance and its metabolic consequences. Leukocyte mobilization, intrahepatic activation, and an exacerbated production of reactive oxygen species (ROS) and cytokines contribute to the development of NASH. Though alterations in peripheral blood (PB) T cell proportions and functionality remain unidentified, they might play a main role in NASH progression. We have compared the phenotype and Th1/Th2 commitment of peripheral immune cell reservoirs in adult patients and controls as well as the ability of neutrophils and monocytes to handle an ex vivo challenge. Also, we correlated those parameters with the main histological characteristics in NASH. Compared with controls, patients showed increased numbers of CD4(+) cells and both CD4(+) and CD8(+) CD45RO subsets together with a higher frequency of IFN-γ-producing CD4(+) and CD8(+) T cells. We also found a decreased number of CD4(+) and CD8(+) CD45RA subsets. The distinctive production of IFN-γ highlights the significance of the observed skewed frequencies of PB T cells. Whereas ROS production by monocytes from NASH patients did not differ from controls, circulating neutrophils displayed a particularly higher phorbol myristate acetate-induced production of ROS. A negative correlation between oxidative burst and fibrosis grade was observed. This study reveals the presence of a characteristic profile of peripheral immune cells in NASH. We also discuss the probable influence of obesity on some of our present findings.

Reduction of skin-homing cytotoxic T cells (CD8+ -CLA+) in patients with vitiligo.

BACKGROUND: Vitiligo is a frequently acquired, hereditary disease, characterized by achromic macules due to the absence of melanocytes. In contrast with earlier studies, in which the main pathogenic role was attributed to anti-melanocyte antibodies, recent papers have emphasized a role for CD8(+) cytotoxic T lymphocytes in melanocyte destruction. Fifteen percent of peripheral T cell express cutaneous lymphocyte-associated antigen (CLA), responsible for skin-homing T cell. Phototherapy is used to treat patients with generalized vitiligo and it has been shown to interfere with CLA(+) T cells in other skin diseases. OBJECTIVE: To describe peripheral blood T cell subpopulations' frequency and ability to express the skin-homing molecule (CLA) in patients with non-segmental vitiligo, before and after photochemotherapy (PUVA). PATIENTS AND METHODS: Twenty-two patients with generalized and active spreading vitiligo were submitted to 30 PUVA-8MOP sessions. Lymphocyte immunophenotyping was performed by flow cytometry using anti-CD3, anti-CD8 and anti-CLA monoclonal antibodies. Fifteen healthy volunteers, sex- and age-matched, were included as a control group. RESULTS: CD8(+) -CLA(+) T cells were significantly reduced in number in untreated vitiligo patients (P=0.008) when compared with control individuals, albeit with a more intense CLA expression (P=0.028). These findings were not altered after PUVA. No significant difference was noticed in CD4/CD8 ratios nor in CD4-CLA(+) T cell numbers between vitiligo patients and controls, both before and after PUVA. CONCLUSIONS: CD8-CLA(+) T cells are reduced in peripheral blood of patients with non-segmental vitiligo. This finding may be related to the previously reported increase of CD8(+) cells in both lesions and perilesional skin of these patients.

Role of CD8+ CD25+ Foxp3+ regulatory T cells in multiple sclerosis.

OBJECTIVE: The objective of this study was to investigate the role of CD8+ CD25+ FoxP3+ cells during the course of multiple sclerosis (MS). METHODS: Peripheral blood and cerebrospinal fluid (CSF) CD8+ T-cell clones (TCCs) recognizing autoreactive CD4+ T cells were isolated from 20 MS patients during exacerbations, 15 patients in remission, 15 healthy subjects, and 10 patients with other inflammatory neurological diseases. Characteristics of noncytotoxic CD8+ CD25+ regulatory T cells were studied. Cell phenotype was evaluated using flow cytometry. Cytokine production and phospho-signal transducer and activator of transcription 3 (STAT3) concentration were determined using enzyme-linked immunosorbent assay. To assess 2,3-dioxygenase (IDO) activity on dendritic cells (DCs), kynurenine concentration was measured by high-performance liquid chromatography. RESULTS: Inhibition of CD4+ self-reactive T-cell proliferation, and of interferon-gamma and interleukin (IL)-17 secretion, was observed after adding CD8+ CD25+ FoxP3+ cells to cultures. Suppression was abrogated by silencing FoxP3 using small interfering RNA. Cells were CD122+, CTLA-4+, GITR+, CCR7+, and CD62L+, producing IL-10 and transforming growth factor-beta. CD8+ CD25+ FoxP3+ cells downregulated costimulatory molecule expression on dendritic cells through a STAT3-mediated pathway, resulting in less efficient antigen presentation, and induced IDO expression on DCs through STAT3 and cytotoxic T-lymphocyte antigen 4-dependent mechanisms. CD8+ regulatory TCC cloning frequency studied in blood and CSF was suppressed to a greater degree during exacerbations than during remission or in controls. Likewise, in CSF of MS patients during acute exacerbations, lower levels of CD8+ CD25+ FoxP3+ T cells were detected using flow cytometry. INTERPRETATION: CD8+ CD25+ FoxP3+ cells are novel regulatory cells exerting significant influence over self-reactive CD4+ T-cell regulation during the course of MS. Induction of these cells may provide new therapeutic alternatives for MS by eliminating or inhibiting self-reactive T cells.

Flow cytometric analysis of T-lymphocytes from nasopharynx-associated lymphoid tissue (NALT) in a model of secondary immunodeficiency in Wistar rats.

Nasopharynx-associated lymphoid tissue (NALT) is responsible for immune responses in the upper respiratory tract of rodents. In our model of protein malnutrition (R21 group), bronchus-associated lymphoid tissue (BALT), situated in the lower respiratory tract, showed a decrease of CD4(+), CD8alpha(+), and TCRalphabeta(+) lymphocytes but TCRgammadelta(+) cells were increased. Besides, there is no information regarding the frequencies of T-cell populations in 60-day-old Wistar rats (C60 group). So, the aim of the present study was to analyze by flow cytometry NALT T-cells from both groups. NALT lymphocytes were isolated from R21 and C60 groups and stained with different antibodies. Samples were run on a FACScalibur flow cytometer. Background staining was evaluated using isotype controls. Data analysis was performed using BD Cell Quest and WinMDI 2.9. In C60, the predominant population was CD4(+)TCRalphabeta(+), which was significantly diminished in the R21 group. However, CD8alpha(+), the majority expressing CD8alphabeta, and TCRgammadelta(+) cells were not affected. In our model of secondary immunodeficiency, there is a compartmentalization between NALT and BALT because they differ in the populations affected even though they are inductive sites of the respiratory tract in the common mucosal immune system.

Trypanosoma cruzi-triggered meningoencephalitis is a CCR1/CCR5-independent inflammatory process.

Encephalitis rarely occurs during acute Trypanosoma cruzi infection. However, the central nervous system (CNS) is the major site of infection reactivation in immunocompromised patients. We show that the acute T. cruzi-triggered CD8-enriched meningoencephalitis paralleled the in situ expression of CCL3/MIP-1alpha and CCL5/RANTES mRNA. The frequency of CCR5-bearing cells was increased among peripheral blood mononuclear cells (PBMC) of infected mice. Further, CCL5/RANTES-driven in vitro PBMC migration was partially abrogated by the CCR1/CCR5 antagonist Met-RANTES. However, Met-RANTES treatment of infected mice altered neither parasitism nor intensity and nature of the CNS inflammation, indicating that T. cruzi-elicited meningoencephalitis is a CCR1/CCR5 independent process.

Altered expression of galectin-3 induces cortical thymocyte depletion and premature exit of immature thymocytes during Trypanosoma cruzi infection.

During acute infection with Trypanosoma cruzi, the causative agent of Chagas' disease, the thymus undergoes intense atrophy followed by a premature escape of CD4+CD8+ immature cortical thymocytes. Here we report a pivotal role for the endogenous lectin galectin-3 in accelerating death of thymocytes and migration of these cells away from the thymus after T. cruzi infection. We observed a pronounced increase in galectin-3 expression that paralleled the extensive depletion of CD4+CD8+ immature thymocytes after infection. In vitro, recombinant galectin-3 induced increased levels of death in cortical immature thymocytes. Consistent with the role of galectin-3 in promoting cell death, thymuses from gal-3-/- mice did not show cortical thymocyte depletion after parasite infection in vivo. In addition, galectin-3 accelerated laminin-driven CD4+CD8+ thymocyte migration in vitro and in vivo induced exportation of CD4+CD8+ cells from the thymus to the peripheral compartment. Our findings provide evidence of a novel role for galectin-3 in the regulation of thymus physiology and identify a potential mechanism based on protein-glycan interactions in thymic atrophy associated with acute T. cruzi infection.

Dendritic cells therapy confers a protective microenvironment in murine pregnancy.

The fetal-placental unit is a semi-allograft and immunological recognition of pregnancy, together with the subsequent response of the maternal immune system, is necessary for a successful pregnancy. Dendritic cells (DC) show a biological plasticity that confers them special characteristics regulating both immunity and tolerance. Therapy employing DC proved to diminish the abortion in the DBA/2J-mated CBA/J females; however, the underlying mechanisms remain unknown. Here, we evaluated whether DC therapy influences the presence of immunoregulatory populations of cells at the fetal-maternal interface. To address this hypothesis, we analysed the pregnancy-protective CD8, gammadelta cell populations as well as transforming growth factor (TGF)-beta1 and progesterone-induced blocking factor (PIBF) expression at the fetal-maternal interface from abortion-prone female mice that had previously received adoptive transfer of syngeneic DC. Syngeneic DC therapy induced an increase in the number of CD8 and gammadelta cells. Additionally, an upregulation of TGF-beta1 and PIBF expression could be detected after DC transfer. We suggest that DC therapy differentially upregulates a regulatory/protective population of cells at the fetal-maternal interface. It is reasonable to assure that this mechanism would be responsible for the lower abortion rate.