Context and location dependence of adaptive Foxp3(+) regulatory T cell formation during immunopathological conditions

Helicobacter pylori infection: How does age influence the inflammatory pattern?

The inflammatory pattern during Helicobacter pylori (H. pylori) infection is changeable and complex. During childhood, it is possible to observe a predominantly regulatory response, evidenced by high concentrations of key cytokines for the maintenance of Treg responses such as TGF-β1 and IL-10, in addition to high expression of the transcription factor FOXP3. On the other hand, there is a predominance of cytokines associated with the Th1 and Th17 responses among H. pylori-positive adults. In the last few years, the participation of the Th17 response in the gastric inflammation against H. pylori infection has been highlighted due to the high levels of TGF-β1 and IL-17 found in this infectious scenario, and growing evidence has supported a close relationship between this immune response profile and unfavorable outcomes related to the infection. Moreover, this cytokine profile might play a pivotal role in the effectiveness of anti-H. pylori vaccines. It is evident that age is one of the main factors influencing the gastric inflammatory pattern during the infection with H. pylori, and understanding the immune response against the bacterium can assist in the development of alternative prophylactic and therapeutic strategies against the infection as well as in the comprehension of the pathogenesis of the outcomes related to that microorganism.

New Insight into Molecular and Hormonal Connection in Andrology

Hormones and cytokines are known to regulate cellular functions in the testes. These biomolecules induce a broad spectrum of effects on various level of spermatogenesis, and among them is the modulation of cell junction restructuring between Sertoli cells and germ cells in the seminiferous epithelium. Cytokines and androgens are closely related, and both correct testicular development and the maintenance of spermatogenesis depend on their function. Cytokines also play a crucial role in the immune testicular system, activating and directing leucocytes across the endothelial barrier to the inflammatory site, as well as in increasing their adhesion to the vascular wall. The purpose of this review is to revise the most recent findings on molecular mechanisms that play a key role in male sexual function, focusing on three specific molecular patterns, namely, cytokines, miRNAs, and endothelial progenitor cells. Numerous reports on the interactions between the immune and endocrine systems can be found in the literature. However, there is not yet a multi-approach review of the literature underlying the role between molecular patterns and testicular and sexual function.

Immune response to Helicobacter pylori infection and gastric cancer development

Gastric adenocarcinoma is a global health concern, and Helicobacter pylori (H. pylori) infection is the main risk factor for its occurrence. Of note, the immune response against the pathogen seems to be a determining factor for gastric oncogenesis, and increasing evidence have emphasized several host and bacterium factors that probably influence in this setting. The development of an inflammatory process against H. pylori involves a wide range of mechanisms such as the activation of pattern recognition receptors and intracellular pathways resulting in the production of proinflammatory cytokines by gastric epithelial cells. This process culminates in the establishment of distinct immune response profiles that result from the cytokine-induced differentiation of T naïve cells into specific T helper cells. Cytokines released from each type of T helper cell orchestrate the immune system and interfere in the development of gastric cancer in idiosyncratic ways. Moreover, variants in genes such as single nucleotide polymorphisms have been associated with variable predispositions for the occurrence of gastric malignancy because they influence both the intensity of gene expression and the affinity of the resultant molecule with its receptor. In addition, various repercussions related to some H. pylori virulence factors seem to substantially influence the host immune response against the infection, and many of them have been associated with gastric tumorigenesis.

Induction of food tolerance is dependent on intestinal inflammatory state

Food allergies are usually managed by food avoidance. Hidden allergens in food, due to cross-contamination and/or allergenic additives added during production, place an important concern in today's increasing food allergy cases worldwide. Previous studies showed that the introduction of unacquainted food components, in an inflamed intestine, results in sensitization to this food. Thus, our aim was to evaluate the kinetics of multiple food allergy induction. Adult male C57BL/6 mice were divided into five groups, four of which were submitted to an intestinal inflammation induction protocol to peanuts. Egg white (OVA) diluted 1:5 v/v in distilled water was instilled by gavage 6h-before (PRIOR), concomitant (AT) and 6h-after (DURING) the onset of the peanut challenge diet. Positive control (POS CONT) and NEG CONT received saline per gavage. Finally, animals were challenged with subcutaneous injections of OVA. Results showed no changes in diet intake were observed. Anti-OVA polyisotypic IgG antibody titers significantly increased in AT. Flow cytometry revealed significant decrease in CD4⁺CD25⁺Foxp3⁺ and significant increase in TCD8⁺ in AT. Histomorphometrically, AT and DURING were classified as Infiltrative and Partial Destruction stages. PRIOR was classified as Infiltrative, while POS CONT was classified as Partial Destruction. NEG CONT was classified as Normal. Together, our results confirm that the introduction of unfamiliar food only a few hours before the initiation of a gut inflammation process is able to induce oral tolerance, however the introduction of a dietary protein concomitant to the onset or during an ongoing gut inflammation may induce multiple allergies.

Association of preoperative EpCAM Circulating Tumor Cells and peripheral Treg cell levels with early recurrence of hepatocellular carcinoma following radical hepatic resection

Background

This study was carried out to determine the prognostic significance of preoperative peripheral epithelial cell adhesion molecule- positive (EpCAM⁺) circulating tumor cell (CTC) and T regulatory (Treg) cell levels in hepatocellular carcinoma (HCC) patients for the prediction of postoperative recurrence following curative resection.

Methods

A total of 49 patients about to undergo curative resection for HCC were recruited into the study. PCR and FACS were used to detect the preoperative levels of EpCAM^mRNA+ CTCs and CD4⁺CD25⁺Foxp3⁺ Treg cells. The prognostic value of EpCAM^mRNA+ CTCs, CD4⁺CD25⁺Foxp3⁺ Treg cells, and other clinicopathological factors were analyzed by applying the Kaplan–Meier method and the multivariate Cox proportional hazards model.

Results

The number of EpCAM^mRNA+ CTCs and Treg/CD4⁺ cells showed significant correlation as prognostic factors of postoperative HCC recurrence: EpCAM^mRNA+ CTC ≥ 2.22 (P = 0.001) and Treg/CD4⁺ ≥ 5.07 (P = 0.045), with EpCAM^mRNA+ CTC ≥ 2.22 (P = 0.003, HR = 6.668) being the most important indicator. Patients with high CTC/Treg levels showed a significantly higher risk of developing postoperative HCC recurrence than those with low CTC/Treg levels (66.7 % vs. 10.3 %, P < 0.001). The high CTC/low Treg group also presented higher 1-year recurrence rates compared with the low CTC/low Treg level group (50.0 % vs. 10.3 %, P = 0.004).

Conclusions

Elevated EpCAM^mRNA+ CTC and Treg/CD4⁺ levels were associated with early recurrence of HCC, indicative of poor clinical outcome. The combined detection of EpCAM^mRNA+ CTC and Treg/CD4⁺ may therefore provide a novel prognostic predictor for HCC patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s12885-016-2526-4) contains supplementary material, which is available to authorized users.

All-trans retinoic acid favors the development and function of regulatory T cells from liver transplant patients

Graft-versus-host disease (GVHD) is an intractable complication in transplant patients. Regulatory T cells (Tregs) have the ability to prevent GVHD and consist of two subsets: natural Tregs (nTregs) and induced Tregs (iTregs). In comparison to nTregs, iTregs originate in the periphery under certain conditions and show improved proliferative and suppressive abilities in an inflammatory milieu. All-trans retinoic acid (atRA) favors Treg expansion and FoxP3 expression in human Tregs. However, whether atRA can affect the function of iTregs from transplant patients remains inconclusive. Therefore, we sorted naïve T cells from liver transplant patients and cultured them in vitro. Further analyses were performed to assess the suppressive function of iTregs in vitro and in vivo. atRA favored expansion and forkhead box P3 expression in iTregs from transplant patients. In comparison to iTregs from healthy donors, iTregs from transplant patients showed decent suppressive abilities in vitro and in vivo. Our findings suggest that atRA can potentially improve the development and function of iTregs from transplant patients. Furthermore, our results provide novel insights into Treg therapy in GVHD clinical trials.

Comparison of circulating and intratumoral regulatory T cells in patients with renal cell carcinoma

The clear evidence that tumor-infiltrating lymphocytes (TIL) exists in the tumor microenvironment raises the question why renal cell carcinoma (RCC) progresses. Numerous studies support the implication of CD4(+)CD25(high) regulatory T (Treg) cells in RCC development. We aimed in this study to characterize the phenotype and function of circulating and intratumoral Treg cells of RCC patient in order to evaluate their implication in the inhibition of the local antitumor immune response. Our results demonstrate that the proportion of Treg in TIL was, in average, similar to that found in circulating CD4(+) T cells of patients or healthy donors. However, intratumoral Treg exhibit a marked different phenotype when compared with the autologous circulating Treg. A higher CD25 mean level, HLA-DR, Fas, and GITR, and a lower CD45RA expression were observed in intratumoral Treg, suggesting therefore that these cells are effector in the tumor microenvironment. Additionally, intratumoral Treg showed a higher inhibitory function on autologous CD4(+)CD25(-) T cells when compared with circulating Treg that may be explained by an overexpression of FoxP3 transcription factor. These findings suggest that intratumoral Treg could be major actors in the impairment of local antitumor immune response for RCC patients.

Comparative Immune Response in Children and Adults with H. pylori Infection

Helicobacter pylori (H. pylori) infection is generally acquired during early childhood; therefore, the immune response which usually takes place at this age may influence or even determine susceptibility to the infection contributing to the clinical outcomes in adulthood. Several cytokines including IL-6, IL-10, and TGF-β1 as well as Foxp3(+) cell numbers have been shown to be higher; however, some other cytokines consisting of IL-1β, IL-17A, and IL-23 are lower in infected children than in infected adults. Immune response to H. pylori infection in children is predominant Treg instead of Th17 cell response. These results indicate that immune system responses probably play a role in persistent H. pylori infection. Childhood H. pylori infection is also associated with significantly lower levels of inflammation and ulceration compared with adults. This review, therefore, aimed to provide critical findings of the available literature about comparative immune system in children and adults with H. pylori infection.

Dual role of immune cells in the testis: Protective or pathogenic for germ cells?

The purpose of this review is to describe how the immune cells present in the testis interact with the germinal epithelium contributing to survival or apoptosis of germ cells (GCs). Physiologically, the immunosuppressor testicular microenvironment protects GCs from immune attack, whereas in inflammatory conditions, tolerance is disrupted and immune cells and their mediators respond to GC self antigens, inducing damage of the germinal epithelium. Considering that experimental models of autoimmune orchitis have clarified the local immune mechanisms by which protection of the testis is compromised, we described the following topics in the testis of normal and orchitic rats: (1) cell adhesion molecule expression of seminiferous tubule specialized junctions and modulation of blood-testis barrier permeability by cytokines (2) phenotypic and functional characteristics of testicular dendritic cells, macrophages, effector and regulatory T cells and mast cells and (3) effects of pro-inflammatory cytokines (TNF-α, IL-6 and FasL) and the nitric oxide-nitric oxide synthase system on GC apoptosis.

Thorax irradiation triggers a local and systemic accumulation of immunosuppressive CD4+ FoxP3+ regulatory T cells

BACKGROUND

Lymphocyte infiltration is a common feature of radiation-induced pneumonitis and fibrosis, but their contribution to the pathogenic processes is still unclear. Here, we addressed the impact of thorax irradiation on the T cell compartment with a focus on immunosuppressive regulatory T cells (Treg).

METHODS

C57BL/6 wild type mice (WT) received anesthesia only (sham controls, 0 Gy) or were exposed to a single dose of whole thorax irradiation (15 Gy). Immune cells from lung tissue, spleen, and cervical lymph nodes were collected 10 to 84 days post-irradiation and phenotypically characterized by flow cytometry.

RESULTS

Whole thorax irradiation provoked an increased influx of CD3+ T cells at 42 and 84 days post-irradiation. In contrast, local irradiation caused a sustained reduction in CD3+ T cells in peripheral lymphoid tissues. Interestingly, we observed a significant local and systemic increase in the fraction of CD4+ T cells expressing the transcription factor forkhead box P3 (FoxP3), the phenotypic marker for murine Treg, at day 21 post-irradiation. The accumulation of Treg was associated with increased levels of T cells expressing surface proteins characteristic for recruitment and immunosuppressive activity, e.g. CD103, CTLA-4 and CD73. Importantly, Treg isolated at this time point were able to suppress CD4+ effector T cells to a similar extent as Treg isolated from control mice.

CONCLUSIONS

The response of the adaptive immune system to whole thorax irradiation is characterized by local immunoactivation and systemic immunosuppression. The transient accumulation of immunosuppressive CD4+ FoxP3+ Treg may be required to protect the lung against excessive inflammation-induced tissue damage. Further investigations shall define the mechanisms underlying the accumulation of Treg and their role for the pathogenesis of radiation-induced lung disease.

Rapamycin regulates iTreg function through CD39 and Runx1 pathways

It has been shown that rapamycin is able to significantly increase the expression of FoxP3 and suppress activity in induced Treg (iTreg) cells in vivo and in vitro. CD39 is a newly determined Treg marker that relates to cell suppression. Runx1, a regulator of FoxP3, controls the expression of adenosine deaminase (ADA) gene, which is found recently in the downstream of CD39 pathway in trophoblast cells. Whether rapamycin would influence CD39 pathway and regulate the expression of Runx1 remains to be determined. The addition of rapamycin to human CD4⁺ naïve cells in the presence of IL-2, TGF-β promotes the expression of FoxP3. In this paper, we found that CD39 positively correlated with the FoxP3 expression in iTreg cells. Rapamycin induced iTreg cells showed a stronger CD39/Runx1 expression with the enhanced suppressive function. These data suggested that CD39 expression was involved in iTreg generation and the enhanced suppressive ability of rapamycin induced Treg was partly due to Runx1 pathway. We conclude that rapamycin favors CD39/Runx1 expression in human iTreg and provides a novel insight into the mechanisms of iTreg generation enhanced by rapamycin.

CD4+ T effectors specific for the tumor antigen NY-ESO-1 are highly enriched at ovarian cancer sites and coexist with, but are distinct from, tumor-associated Treg

Whereas tumor infiltration by T effectors is generally associated with a more favorable prognosis, the accumulation of CD4(+) regulatory T cells (Treg) within tumors is instead often associated with poor disease outcome. Because approaches to improve antitumor immunity aim, on one hand, at expanding tumor antigen-specific T cells and, on the other, at eliminating or inactivating Treg, an outstanding question is whether, and to what extent, tumor antigen-specific CD4(+) T effectors present at tumor sites overlap with tumor-associated Treg. Here, we used MHC class II/peptide tetramers incorporating an immunodominant peptide from the human tumor-specific antigen NY-ESO-1 to assess antigen-specific CD4(+) T cells among conventional CD4(+) T effectors and Treg at sites of ovarian cancer. We found that, in patients who spontaneously respond to the antigen, the frequency of NY-ESO-1 tetramer(+) cells detected ex vivo was highly enriched in tumors as compared with the periphery. At tumor sites, NY-ESO-1 tetramer(+) cells were detected concomitantly with high proportions of Treg but were distinct from the latter and displayed characteristics of TH1 effectors. Thus, even in the presence of high proportions of Treg, tumor antigen-specific CD4(+) T cells can accumulate in ovarian tumors and maintain an effector phenotype.

Cysticerci drive dendritic cells to promote in vitro and in vivo Tregs differentiation

Regulatory T cells (Tregs) play a crucial role in immune homeostasis. Treg induction is a strategy that parasites have evolved to modulate the host's inflammatory environment, facilitating their establishment and permanence. In human Taenia solium neurocysticercosis (NC), the concurrence of increased peripheral and central Treg levels and their capacity to inhibit T cell activation and proliferation support their role in controlling neuroinflammation. This study is aimed at identifing possible mechanisms of Treg induction in human NC. Monocyte-derived dendritic cells (DC) from healthy human donors, cocultivated with autologous CD4⁺ naïve cells either in the presence or absence of cysticerci, promoted CD25^highFoxp3+ Treg differentiation. An increased Treg induction was observed when cysticerci were present. Moreover, an augmentation of suppressive-related molecules (SLAMF1, B7-H1, and CD205) was found in parasite-induced DC differentiation. Increased Tregs and a higher in vivo DC expression of the regulatory molecules SLAMF1 and CD205 in NC patients were also found. SLAMF1 gene was downregulated in NC patients with extraparenchymal cysticerci, exhibiting higher inflammation levels than patients with parenchymal parasites. Our findings suggest that cysticerci may modulate DC to favor a suppressive environment, which may help parasite establishment, minimizing the excessive inflammation, which may lead to tissue damage.

Type 1 diabetes: translating mechanistic observations into effective clinical outcomes

Type 1 diabetes (T1D) remains an important health problem, particularly in western countries, where the incidence has been increasing in younger children. In 1986, Eisenbarth described T1D as a chronic autoimmune disease. Work over the past three-and-a-half decades has identified many of the genetic, immunological and environmental factors that are involved in the disease and have led to hypotheses concerning its pathogenesis. Clinical trials have been conducted to test these hypotheses but have had mixed results. Here, we discuss the findings that have led to our current concepts of the disease mechanisms involved in T1D and the clinical studies promoted by these studies. The findings from preclinical and clinical studies support the original proposed model for how T1D develops but have also suggested that this disease is more complex than was originally thought and will require broader treatment approaches.