Common variable immunodeficiency, cross currents, and prevailing winds.

Common variable immunodeficiency (CVID) is a heterogenous disease category created to distinguish late-onset antibody deficiencies from early-onset diseases like agammaglobulinemia or more expansively dysfunctional combined immunodeficiencies. Opinions vary on which affected patients should receive a CVID diagnosis which confuses clinicians and erects reproducibility barriers for researchers. Most experts agree that CVID's most indeliable feature is defective germinal center (GC) production of isotype-switched, affinity-maturated antibodies. Here, we review the biological factors contributing to CVID-associated GC dysfunction including genetic, epigenetic, tolerogenic, microbiome, and regulatory abnormalities. We also discuss the consequences of these biological phenomena to the development of non-infectious disease complications. Finally, we opine on topics and lines of investigation we think hold promise for expanding our mechanistic understanding of this protean condition and for improving the lives of affected patients.

Lack of p38 activation in T cells increases IL-35 and protects against obesity by promoting thermogenesis.

Obesity is characterized by low-grade inflammation, energy imbalance and impaired thermogenesis. The role of regulatory T cells (Treg) in inflammation-mediated maladaptive thermogenesis is not well established. Here, we find that the p38 pathway is a key regulator of T cell-mediated adipose tissue (AT) inflammation and browning. Mice with T cells specifically lacking the p38 activators MKK3/6 are protected against diet-induced obesity, leading to an improved metabolic profile, increased browning, and enhanced thermogenesis. We identify IL-35 as a driver of adipocyte thermogenic program through the ATF2/UCP1/FGF21 pathway. IL-35 limits CD8+ T cell infiltration and inflammation in AT. Interestingly, we find that IL-35 levels are reduced in visceral fat from obese patients. Mechanistically, we demonstrate that p38 controls the expression of IL-35 in human and mouse Treg cells through mTOR pathway activation. Our findings highlight p38 signaling as a molecular orchestrator of AT T cell accumulation and function.

Treg cells require Izumo1R to regulate γδT cell-driven inflammation in the skin.

Izumo1R is a pseudo-folate receptor with an essential role in mediating tight oocyte/spermatozoa contacts during fertilization. Intriguingly, it is also expressed in CD4+ T lymphocytes, in particular Treg cells under the control of Foxp3. To understand Izumo1R function in Treg cells, we analyzed mice with Treg-specific Izumo1r deficiency (Iz1rTrKO). Treg differentiation and homeostasis were largely normal, with no overt autoimmunity and only marginal increases in PD1+ and CD44hi Treg phenotypes. pTreg differentiation was also unaffected. Iz1rTrKO mice proved uniquely susceptible to imiquimod-induced, γδT cell-dependent, skin disease, contrasting with normal responses to several inflammatory or tumor challenges, including other models of skin inflammation. Analysis of Iz1rTrKO skin revealed a subclinical inflammation that presaged IMQ-induced changes, with an imbalance of Rorγ+ γδT cells. Immunostaining of normal mouse skin revealed the expression of Izumo1, the ligand for Izumo1R, electively in dermal γδT cells. We propose that Izumo1R on Tregs enables tight contacts with γδT cells, thereby controlling a particular path of skin inflammation.

Immunomodulatory and immunoregulatory nanomedicines for autoimmunity.

Autoimmune diseases, caused by cellularly and molecularly complex immune responses against self-antigens, are largely treated with broad-acting, non-disease-specific anti-inflammatory drugs. These compounds can attenuate autoimmune inflammation, but tend to impair normal immunity against infection and cancer, cannot restore normal immune homeostasis and are not curative. Nanoparticle (NP)- and microparticle (MP)-based delivery of immunotherapeutic agents affords a unique opportunity to not only increase the specificity and potency of broad-acting immunomodulators, but also to elicit the formation of organ-specific immunoregulatory cell networks capable of inducing bystander immunoregulation. Here, we review the various NP/MP-based strategies that have so far been tested in models of experimental and/or spontaneous autoimmunity, with a focus on mechanisms of action.

Antibody-mediated blockade of the IL23 receptor destabilizes intratumoral regulatory T cells and enhances immunotherapy.

Regulatory T cells (Treg) can impede antitumor immunity and currently represent a major obstacle to effective cancer immunotherapy. Targeting tumor-infiltrating regulatory Treg while sparing systemic Treg represents an optimal approach to this problem. Here, we provide evidence that the interleukin 23 receptor (IL23R) expressed by tumor-infiltrating Treg promotes suppressive activity. Disruption of the IL23R results in increased responsiveness of destabilized Treg to the IL12 cytokine, the production of γ-interferon, and the recruitment of CD8 T cells that inhibit tumor growth. Since the Treg destabilization pathway that is initiated by IL23R blockade is distinct and independent from the destabilization pathway coupled to glucocorticoid-induced TNFR-related protein (GITR) activation, we examined the impact of the coordinate induction of the two destabilization pathways on antitumor immune responses. Combined GITR and IL23R antibody treatment of mice inoculated with MC38 tumors resulted in robust and synergistic antitumor responses. These findings indicate that the delineation of independent Treg destabilization pathways may allow improved approaches to the development of combination immunotherapy for cancers.

Regulatory T-cell dysfunction and cutaneous exposure to Staphylococcus aureus underlie eczema in DOCK8 deficiency.

BACKGROUND: Dedicator of cytokinesis 8 (DOCK8)-deficient patients have severe eczema, elevated IgE, and eosinophilia, features of atopic dermatitis (AD). OBJECTIVE: We sought to understand the mechanisms of eczema in DOCK8 deficiency. METHODS: Skin biopsy samples were characterized by histology, immunofluorescence microscopy, and gene expression. Skin barrier function was measured by transepidermal water loss. Allergic skin inflammation was elicited in mice by epicutaneous sensitization with ovalbumin (OVA) or cutaneous application of Staphylococcus aureus. RESULTS: Skin lesions of DOCK8-deficient patients exhibited type 2 inflammation, and the patients' skin was colonized by Saureus, as in AD. Unlike in AD, DOCK8-deficient patients had a reduced FOXP3:CD4 ratio in their skin lesions, and their skin barrier function was intrinsically intact. Dock8-/- mice exhibited reduced numbers of cutaneous T regulatory (Treg) cells and a normal skin barrier. Dock8-/- and mice with an inducible Dock8 deletion in Treg cells exhibited increased allergic skin inflammation after epicutaneous sensitization with OVA. DOCK8 was shown to be important for Treg cell stability at sites of allergic inflammation and for the generation, survival, and suppressive activity of inducible Treg cells. Adoptive transfer of wild-type, but not DOCK8-deficient, OVA-specific, inducible Treg cells suppressed allergic inflammation in OVA-sensitized skin of Dock8-/- mice. These mice developed severe allergic skin inflammation and elevated serum IgE levels after topical exposure to Saureus. Both were attenuated after adoptive transfer of WT but not DOCK8-deficient Treg cells. CONCLUSION: Treg cell dysfunction increases susceptibility to allergic skin inflammation in DOCK8 deficiency and synergizes with cutaneous exposure to Saureus to drive eczema in DOCK8 deficiency.

Exosomal-miRNas expression and growth factors released by mononuclear cells of CLAD patients in response to extracorporeal photopheresis.

BACKGROUND: CLAD (Chronic Lung Allograft Dysfunction) remains a serious complication following lung transplantation. Some evidence shows that portions of Extracorporeal Photopheresis (ECP)-treated patients improve/stabilize their graft function. In spite of that, data concerning molecular mechanisms are still lacking. Aims of our study were to assess whether ECP effects are mediated by Mononuclear Cells (MNCs) modulation in term of microRNAs (miRNAs) expression and growth factors release. METHODS: Cells from leukapheresis of 16 CLAD patients, at time 0 and 6-months (10 cycles), were cultured for 48h ± PHA (10 ug/ml) or LPS (2 ug/ml). Expression levels of miR-146a-5p, miR-155-5p, miR-31-5p, miR181a-5p, miR-142-3p, miR-16-5p and miR-23b-5p in MNCs-exosomes were evaluated by qRT-PCR, while ELISA assessed different growth factors levels on culture supernatants. RESULTS: Our result showed miR-142-3p down-regulation (p = 0.02) in MNCs of ECP-patients after the 10 cycles and after LPS stimulation (p = 0.005). We also find miR-146a-5p up-regulation in cells after the 10 cycles stimulated with LPS (p = 0.03). Connective tissue growth factor (CTGF) levels significantly decreased in MNCs supernatant (p = 0.04). The effect of ECP is translated into frequency changes of Dendritic Cell (DC) subpopulations and a slight increase in T regulatory cells (Treg) number and a significant decrease in CTGF release. CONCLUSIONS: ECP might affect regulatory T cell functions, since both miR-142 and miR-146a have been shown to be involved in the regulation of suppressor regulatory T cell functions and DCs. On the other side ECP, possibly by regulating macrophage activation, is able to significantly down modulate CTGF release.

MALT1 inhibition suppresses antigen-specific T cell responses.

The aim of this study was to assess the potential use of a selective small molecule MALT1 inhibitor in solid tumor treatment as an immunotherapy targeting regulatory T-cells (Tregs). In vitro, MALT1 inhibition suppressed the proteolytic cleavage of the MALT1-substrate HOIL1 and blocked IL-2 secretion in Jurkat cells. It selectively suppressed the proliferation of PBMC-derived Tregs, with no effect on conventional CD4+T-cells. In vivo, however, no evident anti-tumor effect was achieved by MALT1 inhibition monotherapy or in combination with anti-CTLA4 in the MB49 cancer model. Despite decreased Treg-frequencies in lymph nodes of tumor-bearing animals, intratumoral Treg depletion was not observed. We also showed that MALT1-inhibition caused a reduction of antigen-specific CD8+T-cells in an adoptive T-cell transfer model. Thus, selective targeting of Tregs would be required to improve the immunotherapeutic effect of MALT1-inhibition. Also, various dosing schedules and combination therapy strategies should be carefully designed and evaluated further.

Egg-sensitised infants have elevated CD4+ effector memory T regulatory cells from birth.

BACKGROUND: IgE-mediated sensitisation to egg is common in infants. In some cases, the processes leading to egg sensitisation are established in early life, even before introduction to solid foods. The underlying mechanisms remain poorly understood. METHODS: We performed detailed immune cell phenotyping of peripheral blood mononuclear cells and determined in vitro cytokine responses following allergen specific and non-specific immune stimulation. To determine if unique immune profiles were linked to early-life egg sensitisation, we compared 92 infants at 4-6 months of age, with (EggCAP+, n = 41) and without (EggCAP-, n = 51) early egg sensitisation. Additionally, 47 cord blood samples were analysed. For a subset of participants (n = 39), matching cord blood mononuclear cells were assessed by flow cytometry to establish the impact of IgE sensitisation on immune developmental trajectories. RESULTS: EggCAP+ infants were found to exhibit a unique immune phenotype characterised by increased levels of circulating CD4+ T regulatory cells (Treg), CD4+ effector memory (EM) Treg and increased expression of the IgE receptor, FcεR1, on basophils. The increased CD4+ EM Treg profiles were already present in cord blood samples from EggCAP+ infants. A general Th2-skewing of the immune system was observed based on increased IL-13 production following phytohemagglutinin stimulation and by comparing immune developmental trajectories, EggCAP+ infants displayed an expansion of basophils and reduced levels of CD4- T cells compared to EggCAP- infants. CONCLUSIONS: Immunological profiles associated with egg sensitisation are detectable in infant circulation at 4-6 months of age and at birth. Understanding the immune mechanisms underlying early-life sensitisation could provide important insights for future food allergy prevention strategies.

Exercise, autoimmune diseases and T-regulatory cells.

Diverse forms of physical activities contribute to improvement of autoimmune diseases and may prevent disease burst. T regulatory cells (Tregs) maintain tolerance in autoimmune condition. Physical activity is one of the key factors causing enhancement of Tregs number and functions, keeping homeostatic state by its secrotome. Muscles secrete myokines like IL-6, PGC1α (PPARγ coactivator-1 α), myostatin, transforming growth factor ß (TGF-ß) superfamily), IL-15, brain derived neurotrophic factor (BDNF) and others. The current concept points to the role of exercise in induction of highly functional and stable muscle Treg phenotype. The residing-Tregs require IL6Rα signaling to control muscle function and regeneration. Skeletal muscle Tregs IL-6Rα is a key target for muscle-Tregs cross-talk. Thus, interplay between the Tregs-skeletal muscle, following exercise, contribute to the balance of immune tolerance and autoimmunity. The cargo delivery, in the local environment and periphery, is performed by extracellular vesicles (EVs) secreted by muscle and Tregs, which deliver proteins, lipids and miRNA during persistent exercise protocols. It has been suggested that this ensemble induce protection against autoimmune diseases.

Engineered Treg cells: The heir to the throne of immunotherapy.

Recently, increased interest in the use of Tregs as adoptive cell therapy for the treatment of autoimmune diseases and transplant rejection had led to several advances in the field. However, Treg cell therapies, while constantly advancing, indiscriminately suppress the immune system without the permanent stabilization of certain diseases. Genetically modified Tregs hold great promise towards solving these problems, but, challenges in identifying the most potent Treg subtype, accompanied by the ambiguity involved in identifying the optimal Treg source, along with its expansion and engineering in a clinical-grade setting remain paramount. This review highlights the recent advances in methodologies for the development of genetically engineered Treg cell-based treatments for autoimmune, inflammatory diseases, and organ rejection. Additionally, it provides a systematized guide to all the recent progress in the field and informs the readers of the feasibility and safety of engineered adoptive Treg cell therapy, with the aim to provide a framework for researchers involved in the development of engineered Tregs.

Cigarette Smoking Is Associated With Lower Chance of Hepatitis B Surface Antigen Seroclearance and Altered Host Immunity.

Cigarette smoking is associated with worse clinical outcomes in patients with chronic hepatitis B (CHB) infection, but the effects on hepatitis B surface antigen (HBsAg) seroclearance are unclear. This study aimed to investigate the effect of active smoking on HBsAg seroclearance (SC) and its impact on peripheral blood lymphocytes in patients with CHB infection. Longitudinal follow-up data was retrieved in 7833 antiviral-treated CHB subjects identified from a centralised electronic patient record database (Part 1). Phenotypic analysis of peripheral blood mononuclear cells (PBMCs) from 27 CHB-infected patients (6 active smokers; 13 with SC) was performed by flow cytometry to assess programmed death-1 (PD-1) expression and proportion of regulatory T cells (CD4+CD25+CD127lo). Effector function of HBV-specific T cells was examined by comparing granzyme B (GZMB) and transforming growth factor beta (TGFß) production in undepleted PBMCs and Treg-depleted PBMCs after 7 days in vitro stimulation with HBV envelope protein overlapping peptides (Part 2). Over a median follow-up of 5 years, smoking was associated with lower probability of SC (aHR 0.70, 95% CI 0.57-0.87). PD-1 expression was increased in CD4+T cells, CD8+T cells and CD20+B cells among smokers compared to non-smokers and positively correlated with pack years (all p < 0.05). Treg depletion led to partial functional recovery of HBV-specific T cells, with significantly bigger magnitude in smokers (p = 0.0451, mean difference = 4.68%) than non-smokers (p = 0.012, mean difference = 4.2%). Cigarette smoking is associated with lower chance of HBsAg seroclearance, higher PD-1 expression on lymphocytes, and impairment of effector functions of HBV-specific T cells in CHB.

The role of regulatory T-cells in the development of endometriosis.

Endometriosis is a benign disease of the female reproductive tract, characterized by the process of chronic inflammation and alterations in immune response. It is estimated to affect 2-19% of women in the general population and is commonly associated with symptoms of chronic pelvic pain and infertility. Regulatory T cells (Treg) are a subpopulation of T lymphocytes that are potent suppressors of inflammatory immune response, essential in preventing destructive immunity in all tissues. In endometriosis, several studies have investigated the possible role of Treg cells in the development of the disease. Most studies to date are heterogeneous in methodology and are based on a small number of cases, which means that it is impossible to define their exact role at present. Based on current knowledge, it seems that disturbed Treg homeostasis, leading to increased systemic and local inflammation within ectopic and eutopic endometrium, is present in women who eventually develop endometriosis. It is also evident that different subsets of human Treg cells have different roles in suppressing the immune response. Recent studies in patients with endometriosis have investigated naive/resting FOXP3lowCD45RA+ Treg cells, which upon T cell receptor stimulation, differentiate into activated/effector FOXP3highCD45RA- Treg cells, characterized by a strong immunosuppressive activity. In addition, critical factors controlling expression of Treg/effector genes, including reactive oxygen species and heme-responsive master transcription factor BACH2, were found to be upregulated in endometriotic lesions. As shown recently for cancer microenvironments, microbial inflammation may also contribute to the local composition of FOXP3+ subpopulations in endometriotic lesions. Furthermore, cytokines, such as IL-7, which control the homeostasis of Treg subsets through the tyrosine phosphorylation STAT5 signalling pathway, have also been shown to be dysregulated. To better understand the role of Treg in the development of endometriosis, future studies should use clear definitions of Tregs along with specific characterization of the non-Treg (FOXP3lowCD45RA-) fraction, which itself is a mixture of follicular Tregs and cells producing inflammatory cytokines.

The T-Cell Growth Factor Interleukin-2, Which Is Occasionally Targeted by Autoantibodies, Qualifies as Drug for the Treatment of Allergy, Autoimmunity, and Cancer: Collegium Internationale Allergologicum (CIA) Update 2024.

Interleukin(IL)-2 was originally characterized as an important T-cellular growth factor but later on, turned out to be a pivotal homeostatic factor for the establishment and maintenance of both natural(n)Treg and peripheral(p)Treg. In this review, it was aimed to connect the peculiar structural and functional aspects of IL-2 to the innovative advancements in tailoring its multifaceted functional behavior for targeting various IL-2 receptor types. The article includes detailed descriptions of modified versions of IL-2, obtained by either mutating or fusing IL-2 to heterologous molecules or by forming IL-2/(monoclonal) antibody complexes (IL-2C), and discusses their functional implications for addressing such heterologous pathological conditions in cancer, autoimmunity, and allergy. Additionally, this review sheds light on the underexplored contribution of autoantibodies to the endogenous regulation of IL-2 within the realms of both health and disease. The ongoing efforts to fine-tune IL-2 responses through antibody-dependent targeting or molecular engineering offer considerable translational potential for the future utility of this important cytokine.

Hypothyroidism-associated immunosuppression involves induction of galectin-1-producing regulatory T cells.

Hypothyroidism exerts deleterious effects on immunity, but the precise role of the hypothalamic-pituitary-thyroid (HPT) axis in immunoregulatory and tolerogenic programs is barely understood. Here, we investigated the mechanisms underlying hypothyroid-related immunosuppression by examining the regulatory role of components of the HPT axis. We first analyzed lymphocyte activity in mice overexpressing the TRH gene (Tg-Trh). T cells from Tg-Trh showed increased proliferation than wild-type (WT) euthyroid mice in response to polyclonal activation. The release of Th1 pro-inflammatory cytokines was also increased in Tg-Trh and TSH levels correlated with T-cell proliferation. To gain further mechanistic insights into hypothyroidism-related immunosuppression, we evaluated T-cell subpopulations in lymphoid tissues of hypothyroid and control mice. No differences were observed in CD3/CD19 or CD4/CD8 ratios between these strains. However, the frequency of regulatory T cells (Tregs) was significantly increased in hypothyroid mice, and not in Tg-Trh mice. Accordingly, in vitro Tregs differentiation was more pronounced in naïve T cells isolated from hypothyroid mice. Since Tregs overexpress galectin-1 (Gal-1) and mice lacking this lectin (Lgals1-/- ) show reduced Treg function, we investigated the involvement of this immunoregulatory lectin in the control of Tregs in settings of hypothyroidism. Increased T lymphocyte reactivity and reduced frequency of Tregs were found in hypothyroid Lgals1-/- mice when compared to hypothyroid WT animals. This effect was rescued by the addition of recombinant Gal-1. Finally, increased expression of Gal-1 was found in Tregs purified from hypothyroid WT mice compared with their euthyroid counterpart. Thus, a substantial increase in the frequency and activity of Gal-1-expressing Tregs underlies immunosuppression associated with hypothyroid conditions, with critical implications in immunopathology, metabolic disorders, and cancer.

Interleukin-1 receptor 1 deficiency worsens hepatocellular carcinoma, while gemcitabine treatment alleviates the hepatocellular carcinoma-induced increase in intra-hepatic immune cells.

BACKGROUND AND AIM: Primary liver cancer, particularly hepatocellular carcinoma (HCC), represents a substantial global health challenge. Although immune checkpoint inhibitors are effective in HCC treatment, several patients still experience disease progression. Interleukin-1 (IL-1) regulates immunity and inflammation. We investigate the role of IL-1 in HCC development and progression and determine the potential therapeutic impact of gemcitabine in treating HCC. METHODS: Hydrodynamics-based transfection, employing the sleeping beauty transposase system, delivered surrogate tumor antigens, NRAS (NRAS proto-oncogene, GTPase), ShP53, and SB100 to C57BL/6 mice. A basic HCC mouse model was established. Pathogen-free animals were tested for serum and hepatotoxicity. The HCC prognosis was monitored using alanine aminotransferase and aspartate aminotransferase levels. Liver histology immunohistochemistry and mouse splenocyte/intra-hepatic immune cell flow cytometry were conducted. IL-1ß levels in human and mouse serum were assessed. RESULTS: Interleukin-1ß levels were elevated in patients with HCC compared with those in non-HCC controls. Hepatic IL-1ß levels were higher in HCC mouse models than those in non-HCC mice, suggesting localized hepatic inflammation. IL-1 receptor type 1 (IL-1R1) knockout (IL-1R1-/-) mice exhibited less severe HCC progression than that in wild-type mice, despite the high intra-hepatic IL-1ß concentration. IL-1R1-/- mice exhibited increased hepatic levels of myeloid-derived suppressor cells and regulatory T cells, which may exacerbate HCC. Gemcitabine significantly reduced the HCC tumor burden, improved liver conditions, and increased survival rates in HCC mouse models. Gemcitabine reduced the hepatic levels of myeloid-derived suppressor cells and regulatory T cells, potentially alleviating immune suppression in the liver. CONCLUSIONS: Targeting IL-1 or combining gemcitabine with immunotherapy is a promising approach for treating advanced-stage HCC.

Quantitative analysis of Tr1 lymphocytes in patients with type 2 diabetes mellitus.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is usually accompanied by a low-grade inflammatory phenomenon, which participates in the pathogenesis of different complications of this condition. The inflammatory response is under the regulation of different mechanisms, including T regulatory (Treg) lymphocytes. However, the possible role of type 1 T regulatory (Tr1) cells in T2DM has not been explored so far. AIM: To carry out a quantitative analysis of Tr1 lymphocytes and other immune cell subsets in patients with T2DM and correlate these results with clinical findings and treatments. MATERIALS AND METHODS: Sixty patients with T2DM and twenty-three healthy controls were included in the study. Biochemical and anthropometric variables were evaluated, and Tr1 lymphocytes (CD4+CD49+LAG-3+IL-10+) and other cell subsets (Th17, Th22 and Foxp3 + Treg cells) were analyzed in peripheral blood samples by multiparametric flow cytometry. RESULTS: Significant increased levels of Tr1 cells were detected in patients with severe and mild disease, compared to healthy controls. In addition, CD4+IL-10+ lymphocytes were also increased in patients with T2DM. In contrast, similar levels of Foxp3+ Treg cells, Th17 and Th22 lymphocytes were observed in patients and controls. Likewise, no significant associations were detected between Tr1 cell levels and different clinical and laboratory parameters. However, those patients receiving glucagon-like peptide-1 receptor agonists (GLP-1-RA) showed similar levels of Tr1 cells than healthy controls, and significant lower numbers than untreated patients. CONCLUSION: We observed an increase in Tr1 and CD4+IL10+ lymphocyte levels in T2DM. Moreover, GLP1-RA treatment was significantly associated with normalization of the Tr1 levels. This highlights another potential immune dysfunction in patients with T2DM, which could participate in the pathogenesis of this condition.

PIP4Ks impact on PI3K, FOXP3, and UHRF1 signaling and modulate human regulatory T cell proliferation and immunosuppressive activity.

Regulatory T cells (Tregs) play fundamental roles in maintaining peripheral tolerance to prevent autoimmunity and limit legitimate immune responses, a feature hijacked in tumor microenvironments in which the recruitment of Tregs often extinguishes immune surveillance through suppression of T-effector cell signaling and tumor cell killing. The pharmacological tuning of Treg activity without impacting on T conventional (Tconv) cell activity would likely be beneficial in the treatment of various human pathologies. PIP4K2A, 2B, and 2C constitute a family of lipid kinases that phosphorylate PtdIns5P to PtdIns(4,5)P2 They are involved in stress signaling, act as synthetic lethal targets in p53-null tumors, and in mice, the loss of PIP4K2C leads to late onset hyperinflammation. Accordingly, a human single nucleotide polymorphism (SNP) near the PIP4K2C gene is linked with susceptibility to autoimmune diseases. How PIP4Ks impact on human T cell signaling is not known. Using ex vivo human primary T cells, we found that PIP4K activity is required for Treg cell signaling and immunosuppressive activity. Genetic and pharmacological inhibition of PIP4K in Tregs reduces signaling through the PI3K, mTORC1/S6, and MAPK pathways, impairs cell proliferation, and increases activation-induced cell death while sparing Tconv. PIP4K and PI3K signaling regulate the expression of the Treg master transcriptional activator FOXP3 and the epigenetic signaling protein Ubiquitin-like containing PHD and RING finger domains 1 (UHRF1). Our studies suggest that the pharmacological inhibition of PIP4K can reprogram human Treg identity while leaving Tconv cell signaling and T-helper differentiation to largely intact potentially enhancing overall immunological activity.

Effect of Short Peptides of Pregnancy-Specific ß1-Glycoprotein on Differentiation of Human Regulatory T Cells In Vitro and on Their Cytokine Profile.

Pregnancy-specific ß1-glycoprotein (PSG), one of the most important proteins of pregnancy, has a pronounced immunosuppressive effect. Short peptides of PSG, the so-called SLiMs (short linear motifs), are promising molecules for mild immunosuppression. We studied in vitro effect of short PSG peptides (YACS, YQCE, YVCS, and YECE) on differentiation and cytokine profile of human T-regulatory lymphocytes (Treg). T helpers isolated from the peripheral blood and polarized into the Treg phenotype with a T-cell activator (anti-CD2/3/28) and the cytokines IL-2 and transforming grown factor ß (TGFß) were used. PSG peptides were shown to have no direct modulatory effect on Treg differentiation in a culture of CD4+ cells polarized to the Treg phenotype. At the same time, PSG peptides had no effect on the viability and number of CD4+ cells in the in vitro culture. PSG peptides also had no effect on the levels of TNFα, IL-8, IL-2, macrophage inflammatory protein 1ß, IL-17, IL-10, IL-6, granulocyte-macrophage CSF, monocyte chemoattractant protein 1, IL-13, IL-5, IL-7, IL-12(p70), IL-1ß, granulocyte CSF, IL-4, but decreased IFNγ levels. The observed ability of the YQCE peptide to reduce the production of this proinflammatory Th1 cytokine by T helper cells can be interpreted as a positive effect. Our findings can be used for further development of safe peptide drugs based on SLiMs sequences.

Immunomodulatory action of synbiotic comprising of newly isolated lactic acid producing bacterial strains against allergic asthma in mice.

Given the reported role of gut-microbiota in asthma pathogenesis, the present work was carried to evaluate immunomodulatory action of newly isolated lactic acid producing bacterial strains Bifidobacterium breve Bif11 and Lactiplantibacillus plantarum LAB31 against asthma using ovalbumin (OVA) based mouse model. Our results show that both strains modulate Th2 immune response potentially through production of short chain fatty acids (SCFAs), resulting in suppression of OVA-induced airway inflammation. Furthermore, synbiotic comprising of both strains and prebiotic, Isomaltooligosaccharide exhibited superior potential in amelioration of OVA-induced airway inflammation through improved modulation of Th2 immune response. Further, synbiotic protects against OVA-induced mucus hyper-production and airway-hyperresponsiveness. Such protection was associated with normalization of gut microbiome and enhanced production of SCFAs in cecum which correlates closely with population of T-regulatory cells in spleen. Overall, our novel synbiotic possesses the ability to fine-tune the immune response for providing protection against allergic asthma.