Th1 Induction Research Articles

Itaconate Ameliorates Experimental Autoimmune Uveitis by Modulating Teff/Treg Cell Imbalance Via the DNAJA1/CDC45 Axis.

The aim of this study was to elucidate the effect of itaconate (ITA) on experimental autoimmune uveitis (EAU), to explore its potential mechanism, and to identify potential therapeutic targets. We established an animal model of EAU by constructing an immune map of mice treated with ITA and exploring the therapeutic mechanism of ITA by single-cell RNA sequencing and flow cytometry. ITA mitigated ocular inflammation associated with EAU and reversed the pathogenic differentiation linked to Th17 induction by EAU, along with the reactive oxygen species (ROS) and oxidative stress pathways. Subsequent to ITA intervention, the downregulated differentially expressed genes in the T-cell subset primarily centered around the heat shock protein (HSP) family. Activation of HSPs reversed the anti-inflammatory effects of ITA in EAU mice. ITA decreased ROS levels and HSP expression in CD4+ T cells, with DnaJ heat shock protein family (HSP40) member A1 (DNAJA1) exhibiting the most notable alterations among the HSPs. ITA suppressed the expression of DNAJA1/cell division cycle protein 45 (CDC45), thereby disrupting the pathogenic division cycle of CD4+ T cells and reducing their proliferation. Inhibiting DNAJA1 also held promise for modulating the Th17/Treg imbalance. Notably, ITA curtailed the expansion of CD4+ T cells in uveitis patients. Our research delved into the potential therapeutic mechanisms underlying ITA therapy in EAU, offering fresh perspectives on its utility in the treatment of autoimmune conditions. DNAJA1 emerges as a promising candidate for targeted therapeutic interventions in uveitis.

Dihydroberberine alleviates Th17/Treg imbalance in premature ovarian insufficiency mice via inhibiting Rheb/mTOR signaling

BackgroundPremature ovarian insufficiency (POI) is an immune-related condition. Dihydroberberine (dhBBR) plays a regulatory role in maintaining the T-helper 17 (Th17)/regulatory T (Treg) cell balance. This study aimed to explore the action mechanisms of dhBBR on POI.MethodsIn vivo, female BALB/c mice were used as POI models, treated with dhBBR, or injected with recombinant interleukin (rIL)-17 and anti-CD25 monoclonal antibody. Hematoxylin and eosin staining was used to validate the model and assess the therapeutic effects of dhBBR. mRNA expression levels of cytochrome P450 (Cyp)-17a1, Cyp19a1, Cyp11a1, steroidogenic acute regulatory protein, and luteinizing hormone receptor in mouse ovaries were quantified via quantitative polymerase chain reaction (qPCR). Enzyme-linked immunosorbent assay was used to determine the cytokine and sex hormone levels. Immunohistochemical staining for cleaved-caspase 3 and Ki-67 were performed to assess ovarian cell apoptosis and proliferation. Flow cytometry was used to analyze the Th17/Treg cell balance in the ovary and spleen. In vitro cytotoxicity of dhBBR was measured using the cell counting kit-8 assay. GTP-Ras homolog enriched in brain (Rheb) activity was determined via immunofluorescence assay. Co-immunoprecipitation was performed to assess Rheb activity, Th17 or Treg induction, and binding between Rheb and mammalian target of rapamycin (mTOR) after dhBBR treatment. Flow cytometry and qPCR assays were used to verify the effect of dhBBR on CD4 + cell differentiation. Finally, Rheb/mTOR pathway activation was confirmed via western blotting of proteins, including mTOR, p-mTOR, p70S6K, p-p70S6K, 4E-BP1, and p-4E-BP1.ResultsdhBBR improved the ovarian function in a dose-dependent manner. It also decreased ovarian cell apoptosis and increased cell proliferation. It decreased Th1 and Th17 cell proportions but increased Treg cell proportions in the ovaries and spleens of POI model mice. Cell experiments revealed that dhBBR promoted CD4 + cell differentiation into Treg cells. Co-immunoprecipitation revealed Rheb as the dhBBR target that bound to mTOR. However, MHY1485 restored dhBBR-induced changes in forkhead box P3, IL-10, transforming growth factor-β1, IL-17, IL-22, retinoic acid-related orphan receptor-γt and p-mTOR levels in Th17- and Treg-induced CD4 + cells.ConclusionOverall, dhBBR targeted the Rheb/mTOR pathway to promote CD4 + cell differentiation into Treg cells and alleviate POI.

Silencing TRIM8 alleviates allergic asthma and suppressing Th2 differentiation through inhibiting NF-κB/NLRP3 signaling pathway

Background and aimAllergic asthma is a primary type of asthma and characterized by T helper 2 (Th2) cells -mediated inflammation. Tripartite motif containing 8 (TRIM8) protein is involved in immunoreaction and inflammatory response in many diseases. However, its role in allergic asthma remains unclear. Medical databank showed that TRIM8 was increased in lung of ovalbumin (OVA)-challenged mice. This study aimed to elucidate the effects of TRIM8 on allergic asthma and Th2 development. MethodsAsthma were induced by OVA challenge in mice, and the adenovirus vector loaded with TRIM8 knockdown sequence was delivered into asthma mice by nasal inhalation. The percentage of Th2 cells in lung was assessed by flow cytometric analysis, and the contents of Th2 cytokines (interleukin (IL)-4, IL-5 and IL-13) in bronchoalveolar lavage fluid (BALF) were assessed with ELISA. In vitro Th2 induction was performed in CD4+ cells from mouse spleen, the expression of Th2 molecules (IL-4, IL-5 and GATA binding protein 3 (GATA3)) were measured by real-time PCR. In addition, the nuclear factor-kappa B (NF-κB)/nucleotide-binding oligomerization domain, leucine rich repeat and pyrin domain containing 3 (NLRP3) signaling was determined. ResultsTRIM8 was highly expressed in the lung tissues of asthmatic mice and Th2-induced CD4+ cells. OVA challenge-induced Th2 development and Th2 cytokine secretion were restrained by silencing of TRIM8 in vivo. Similarly, the Th2 differentiation in vitro was also suppressed by TRIM8 knockdown. TRIM8 inhibited the NF-κB/NLRP3 activity by blocking transforming growth factor-beta-activated kinase 1 (TAK1), and the effects of TRIM8 were abrogated by overexpression of NLRP3. ConclusionsSilencing TRIM8 relieved the asthmatic injury in mice and excessive Th2 development via inhibiting the NF-κB/NLRP3 pathway. It is indicated that TRIM8 may contribute to the airway inflammation in allergic asthma via activating the NF-κB/NLRP3 signaling pathway. The current study provided a novel potential target for allergic asthma treatment.

Lactococcus lactis subsp. cremoris YRC3780 modifies function of mesenteric lymph node dendritic cells to modulate the balance of T cell differentiation inducing regulatory T cells.

The intestinal immune system plays a pivotal role in the induction of immune responses against food. In the case of T cell response, dendritic cells (DCs) are especially important. However, the regulation of immune responses to food by intestinal DCs has been poorly described. In this study, we analyzed the effect of Lactococcus lactis subsp. cremoris YRC3780, a lactic acid bacterial strain isolated from kefir, a traditional fermented milk product, on the immune responses induced by antigen presentation by intestinal DCs to T cells as well as the mechanism of action of these immunomodulatory effects. It has been shown that L. cremoris YRC3780 ameliorates the symptoms of pollinosis in both animal and human studies. CD11c+ cells from mesenteric lymph nodes (MLNs) of BALB/c mice were cultured as MLN DCs with L. cremoris YRC3780 and expression of genes inducing regulatory T cells (Tregs) was examined by qPCR. In addition, MLN DCs were cocultured with CD4+ T cells from DO11.10 transgenic mice expressing an ovalbumin (OVA)-specific TCR and the OVA antigen peptide and L. cremoris YRC3780. Induction of Tregs was examined by flow cytometry, gene expression was analyzed by DNA microarray and qPCR, and the production of cytokines was measured by ELISA. MLN DCs from TLR2-deficient mice and components of L. cremoris YRC3780 were used to examine the recognition of YRC3780 by MLN DCs. L. cremoris YRC3780 enhanced the expression of genes involved in Treg induction in MLN DCs and induced Foxp3+CD4+T cells in an MLN DC and CD4+ T-cell co-culture system. The effect on MLN DCs was likely mediated by receptors other than TLR2. Together with microarray analyses of CD4+ T cell gene expression and cytokine ELISA, it was demonstrated that L. cremoris YRC3780 promoted the induction of Th1 and Tregs, and regulated the balance of Th1/Th2 and Treg/Th17 cells involving multiple genes via the antigen-presentation of MLN DCs. Our findings provide insights into the modulation of intestinal immune responses mediated by DCs and the antiallergic effects of lactic acid bacteria.

Impaired autophagy in myeloid cells aggravates psoriasis-like skin inflammation through the IL-1β/CXCL2/neutrophil axis

BackgroundPsoriasis is an inflammatory skin disease characterized by the hyperproliferative epidermal keratinocytes and significant immune cells infiltration, leading to cytokines production such as IL-1β, TNF-α, IL-23, and IL-17. Recent study highlights the critical role of IL-1β in the induction and activation of pathogenic Th17 and IL-17-producing γδ T cells, contributing to psoriasis. However, the mechanism underlying IL-1β dysregulation in psoriasis pathogenesis is unclear. Autophagy regulates IL-1β production and has a pleiotropic effect on inflammatory disorders. Previous studies showed controversial role of autophagy in psoriasis pathogenesis, either pro-inflammatory in autophagy-deficient keratinocyte or anti-inflammatory in pharmacologically autophagy-promoting macrophages. Thus, the direct role of autophagy and its therapeutic potential in psoriasis remains unclear.MethodsWe used myeloid cell-specific autophagy-related gene 7 (Atg7)-deficient mice and determined the effect of autophagy deficiency in myeloid cells on neutrophilia and disease pathogenesis in an imiquimod-induced psoriasis mouse model. We then assessed the pathogenic mechanism focusing on immune cells producing IL-1β and IL-17 along with gene expression profiles associated with psoriasis in mouse model and public database on patients. Moreover, therapeutic potential of IL-1β blocking in such context was assessed.ResultsWe found that autophagy deficiency in myeloid cells exacerbated neutrophilic inflammation and disease pathogenesis in mice with psoriasis. This autophagy-dependent effect was associated with a significant increase in IL-1β production from myeloid cells, particularly macrophages, Cxcl2 expression, and IL-17 A producing T cells including γδ T cells. Supporting this, treatment with systemic IL-1 receptor blocking antibody or topical saccharin, a disaccharide suppressing pro-IL-1β expression, led to the alleviation of neutrophilia and psoriatic skin inflammation linked to autophagy deficiency. The pathophysiological relevance of this finding was supported by dysregulation of autophagy-related genes and their correlation with Th17 cytokines in psoriatic skin lesion from patients with psoriasis.ConclusionsOur results suggest that autophagy dysfunction in myeloid cells, especially macrophages, along with IL-1β dysregulation has a causal role in neutrophilic inflammation and psoriasis pathogenesis.

High-mannose glycans from Schistosoma mansoni eggs are important for priming of Th2 responses via Dectin-2 and prostaglandin E2.

The parasitic helminth Schistosoma mansoni is a potent inducer of type 2 immune responses by stimulating dendritic cells (DCs) to prime T helper 2 (Th2) responses. We previously found that S. mansoni soluble egg antigens (SEA) promote the synthesis of Prostaglandin E2 (PGE2) by DCs through ERK-dependent signaling via Dectin-1 and Dectin-2 that subsequently induces OX40L expression, licensing them for Th2 priming, yet the ligands present in SEA involved in driving this response and whether specific targeting of PGE2 synthesis by DCs could affect Th2 polarization are unknown. We here show that the ability of SEA to bind Dectin-2 and drive ERK phosphorylation, PGE2 synthesis, OX40L expression, and Th2 polarization is impaired upon cleavage of high-mannose glycans by Endoglycosidase H treatment. This identifies high-mannose glycans present on glycoproteins in SEA as important drivers of this signaling axis. Moreover, we find that OX40L expression and Th2 induction are abrogated when microsomal prostaglandin E synthase-1 (mPGES) is selectively inhibited, but not when a general COX-1/2 inhibitor is used. This shows that the de novo synthesis of PGE2 is vital for the Th2 priming function of SEA-stimulated DCs as well as points to the potential existence of other COX-dependent lipid mediators that antagonize PGE2-driven Th2 polarization. Lastly, specific PGE2 inhibition following immunization with S. mansoni eggs dampened the egg-specific Th cell response. In summary, our findings provide new insights in the molecular mechanisms underpinning Th2 induction by S. mansoni and identify druggable targets for potential control of helminth driven-Th2 responses.

Sirtuin2 suppresses the polarization of regulatory T cells toward T helper 17 cells through repressing the expression of signal transducer and activator of transcription 3 in a mouse colitis model.

Regulatory T cells (Tregs) play an important role in inflammatory bowel diseases (IBDs) through modulating intestinal inflammation. However, the factors affecting Treg function and plasticity during IBD progression are not thoroughly disclosed. The current study aims to reveal new molecular mechanisms affecting Treg plasticity. A mouse strain, in which tdTomato and enhanced green fluorescent protein were under the control of the Foxp3 promoter and Il17a promoter, was established and subjected to colitis induction with dextran sulfate sodium. The existence of Tregs and IL-17-expressing Tregs (i.e., Treg/T helper 17 [Th17] cells) were observed and sorted from the spleen, mesenteric lymph nodes, and lamina propria by flow cytometry, followed by measuring Sirtuin2 (Sirt2) expression using quantitative reverse transcription polymerase chain reaction and Immunoblotting. Lentivirus-induced Sirt2 silencing was applied to determine the impact of Sirt2 on Treg polarization to Treg/Th17 cells and even Th17 cells. The effect of Sirt2 on Stat3 was analyzed by flow cytometry and immunoblotting. Sirt2 was highly expressed in lamina propria Tregs and it moderately suppressed Foxp3 expression as well as the immunosuppressive function of Tregs. Surprisingly, lentivirus-mediated Sirt2 silencing promoted the generation of Treg/Th17 cells out of Tregs. Sirt2 silencing also enhanced the generation of Th17 cells out of Tregs under the Th17 induction condition. Furthermore, Sirt2 inhibited Th17 induction by suppressing the protein level of the signal transducer and activator of transcription 3. Sirt2 suppresses Treg function but also inhibits Treg polarization toward Treg/Th17 cells and Th17 cells. The ultimate effect of Sirt2 on colitis might depend on the balance among Tregs, Treg/Th17 cells, and Th17 cells.

T helper cell responses to Opisthorchis viverrini infection associate with host susceptibility.

Opisthorchis viverrini infection is endemic in the lower Mekong subregion. The liver is an organ that worms are drawn to and cause damage. However, the immune-related susceptibility in the liver is poorly understood. In this study, we investigated T helper (Th) cell responses in the liver of BALB/c mice and golden Syrian hamsters during 2-28days post-infection (DPI). We found that Th cell responses were distinct between mice and hamsters in terms of dynamics and polarization. Mice exhibited the early induction of Th1, Th2, Th17, and regulatory T (Treg) cells responses after the presence of O. viverrini worms at 2 DPI. In hamsters, the late induction of Th1/Th17, downregulation of Th2/Treg responses and early elevation of suppressive cytokine interleukin (IL)-10 were found together with swift reduction of Th cell numbers. Interestingly, expressions of IL-4 (Th2 functional cytokine) and Foxp3 (Treg lineage) were completely different between mice and hamsters which elevated in mice but suppressed in hamsters. These results suggest that early induction and well-regulation are related to host resistance. In contrast, late induction of Th cell response might allow immature worms to develop in the host. Our findings provide a greater understanding in Th cell response-related susceptibility in O. viverrini infection which would be targeting immunity for the development of immune-based intervention such as vaccine.

P470 Crohn’s disease patients with Ustekinumab-induced remission are characterized by high baseline p35 cytokines subunits in LPMC and high IL-23 receptor expression in the lamina propria Th1 cells

Abstract Background Crohn’s disease (CD) is a chronic relapsing disorder of the gastrointestinal tract characterized by excessive inflammation sustained by the induction and expansion of Th1 and Th17 cells. Ustekinumab (UST), a fully humanized monoclonal antibody, is currently used for the therapy of CD patients. It acts by neutralizing both IL12 and IL23, essential for the maturation and expansion of Th1 and Th17 cells, by binding the common subunit p40. To be effective UST needs, in addition to the expression of target cytokines, the presence of cells responsive to IL12 and IL23, thus cells with IL12 and IL23 receptors. Methods This is a prospective, observational, single-center open-label study. All CD patients with clinical indications to receive UST for active luminal disease were enrolled. Patients had baseline endoscopy to confirm disease activity by SES-CD and to collect biopsies to isolate LPMC. Real-time pcr was performed to evaluate IL12 (p40 and p35) and IL23 (p40 and p19) cytokines subunits and IL12 (IL12Rb1 and IL12Rb2) and IL23 (IL12Rb1 and IL23R) receptors subunits expression in remitters (R) and not remitters (NR). Moreover, LPMCs were analyzed by flow cytometry, and IL12Rb2 and IL23R expression in Th1, Th17, and type 1 Innate lymphoid cells (iLC) cells were evaluated. Results were analyzed for clinical remission status (HBI<5) at week 16. Differences between groups were analyzed by Mann-Whitney test and statistical significance was considered for p<0.05. Results From April 2019 to November 2022, 13 CD patients were enrolled, whose clinical and demographic characteristics are enclosed in Table 1. At baseline there was no difference in IL12Rb2, ILRb1, and IL23R expression between R and NR (Fig.1). Regarding cytokines subunits, there was no difference in p19 but there was a significantly higher expression of p35 subunits in R than in NR (mean 1,52 vs 0,34; p=0,001) (Fig.1). Flow cytometry showed no difference in Th and ILCs subgroups frequency between R and NR. IL12Rb2 and IL23R were also equally expressed by Th17, Th1/Th17 and ILC1 cells in the two groups. In contrast, Th1 cells, IL23R expression was higher in R group as compared to NR (mean 20,6% vs 6,8; p=0.009) (Fig.2). Conclusion In CD patients treated with UST, higher expression p35 in LPMC and higher expression of IL23R in the lamina propria Th1 cells was associated with remission at week 16.

The Klebsiella mannose phosphotransferase system promotes proliferation and the production of extracellular polymeric substances from mannose, facilitating adaptation to the host environment

ObjectivesKlebsiella spp., an opportunistic infectious organism, is commensal in the nasal and oral cavities of humans. Recently, it has been reported that oral Klebsiella spp. ectopically colonize the intestinal tract and induce the accumulation of intestinal Th1 cells. For oral bacteria to colonize the intestinal tract, they need to compete for nutrients with indigenous intestinal bacteria. Therefore, we focused on mannose, a mucus-derived sugar, and the mannose phosphotransferase system (PTS) (ManXYZ), a mechanism for mannose uptake, in terms of their effects on intestinal colonization and immune responses to Klebsiella spp. MethodsWe generated a Klebsiella manXYZ-deficient strain and investigated whether the utilization of intestinal mucus-derived sugars is associated with the growth. Furthermore, we examine the virulence of this organism in the mouse intestinal tract, especially the ability to colonize the host using competition assay. ResultsWe found that Klebsiella ManXYZ is a PTS that specifically takes up mannose and glucosamine. Through ManXYZ, mannose was used for bacterial growth and the upregulated production of extracellular polymeric substances. In vivo competition assays showed that mannose metabolism promoted intestinal colonization. However, ManXYZ was not involved in Th1 and Th17 induction in the intestinal tract. ConclusionThe fundamental roles of ManXYZ were to ensure that mannose, which is present in the host, is made available for bacterial growth, to promote the production of extracellular polymeric substances, thus facilitating bacterial adaptation to the host environment.

Card9/neutrophil signalling axis promotes IL-17A-mediated ankylosing spondylitis

ObjectivePolymorphisms in the antifungal signalling molecule CARD9 are associated with ankylosing spondylitis (AS). Here, we investigated the cellular mechanism by which CARD9 controls pathogenic Th17 responses and the onset of...

Identification of a potential antigen stimulating immune response against Vibrio parahaemolyticus infection in hybrid tilapia (Oreochromis aureus♂ × Oreochromis niloticus♀).

Vibrio parahaemolyticus (V. parahaemolyticus) is a major pathogen that causes substantial losses in the marine fishery. With the emergence of antibiotic resistance, vaccines have become the most effective approach against V. parahaemolyticus infection. Adhesion factors on the cell surface are pivotal in the colonization and pathogenesis of V. parahaemolyticus within the host, highlighting their potential as vaccine candidates. This study aims to assess the immunogenicity and potential of recombinant V. parahaemolyticus MAM7 (rMAM7) as a vaccine candidate. Initially, we cloned and purified the MAM7 protein of V. parahaemolyticus. Moreover, after 4 weeks of vaccination, the fish were challenged with V. parahaemolyticus. rMAM7 demonstrated a certain protective effect. Immunological analysis revealed that rMAM7 immunization-induced antibody production and significantly increased acid phosphatase (ACP) and alkaline phosphatase (AKP) activity in hybrid tilapia. Furthermore, serum bactericidal tests demonstrated a lower bacterial survival rate in the rMAM7 group compared to PBS and rTrxa. qRT-PCR results indicated that rMAM7 significantly upregulated CD4, CD8 and IgM gene expression, suggesting the induction of Th1 and Th2 responses in hybrid tilapia. Overall, these findings highlight the potential application of MAM7 from V. parahaemolyticus in the development of protein vaccines.

Diphtheria Toxoid Particles as Q Fever Vaccine

AbstractThere is an unmet need for a stable and nonreactogenic vaccine against the bioterrorism agent, Coxiella burnetii, causing Q fever. Here a safe, effective, and non‐reactogenic Q fever vaccine is developed by employing self‐assembled particles (CPs) composed of cross‐reacting material 197, a nontoxic variant of diphtheria toxin. CPs are designed that incorporate selected C. burnetii antigens and assemble them inside engineered Escherichia coli at high yields. A cost‐effective manufacturing process enables the production of CP‐based Q fever vaccine candidates. Four vaccine candidates are developed, including a T‐cell epitope‐based vaccine (CP‐COX), and one that comprises two immunodominant antigens, Com1 and YbgF. The latter is tested separately (CP‐Com1, CP‐YbgF) or as a mixture (CP‐Com1/CP‐YbgF). Initial immunogenicity studies in mice reveal that the mixed CP‐Com1/YbgF elicits the highest antibody titers with a half maximal effective concentration (EC50) value of ≈100 000 and induction of TH1 and TH2 cytokines. CP‐Com1/YbgF is further evaluated in guinea pigs, demonstrating its safety and efficacy, as shown by the absence of adverse reactions and a significant reduction in febrile responses compared to alum upon challenge with C. burnetii. Together, the study shows the potential of CPs for the development of a safe and immunogenic subunit Q fever vaccine.

Administration of soluble gp130Fc disrupts M-1 macrophage polarization, dendritic cell activation, MDSC expansion and Th-17 induction during experimental cerebral malaria

Regulatory effect of IL-6 on various immune cells plays a crucial role during experimental cerebral malaria pathogenesis. IL-6 neutralization can restore distorted ratios of myeloid dendritic cells and plasmacytoid dendritic cells as well as the balance between Th-17 and T-regulatory cells. IL-6 can also influence immune cells through classical and trans IL-6 signalling pathways. As trans IL-6 signalling is reportedly involved during malaria pathogenesis, we focused on studying the effects of trans IL-6 signalling blockade on various immune cell populations and how they regulate ECM progression. Results show that administration of sgp130Fc recombinant chimera protein lowers the parasitemia, increases the survivability of Plasmodium berghei ANKA infected mice, and restores the distorted ratios of M1/M2 macrophage, mDC/pDC, and Th-17/Treg. IL-6 trans signalling blockade has been found to affect both expansion of myeloid derived suppressor cells (MDSCs) and expression of inflammatory markers on them during Plasmodium berghei ANKA infection indicating that trans IL-6 signalling might regulate various immune cells and their function during ECM. In this work for the first time, we delineate the effect of sgp130Fc administration on influencing the immunological changes within the host secondary lymphoid organ during ECM induced by Plasmodium berghei ANKA infection.

Recombinant BCG expressing the LTAK63 adjuvant increased memory T cells and induced long-lasting protection against Mycobacterium tuberculosis challenge in mice.

Vaccine-induced protection against Mycobacterium tuberculosis (Mtb) is usually ascribed to the induction of Th1, Th17, and CD8+ T cells. However, protective immune responses should also involve other immune cell subsets, such as memory T cells. We have previously shown improved protection against Mtb challenge using the rBCG-LTAK63 vaccine (a recombinant BCG strain expressing the LTAK63 adjuvant, a genetically detoxified derivative of the A subunit from E. coli heat-labile toxin). Here we show that mice immunized with rBCG-LTAK63 exhibit a long-term (at least until 6 months) polyfunctional Th1/Th17 response in the draining lymph nodes and in the lungs. This response was accompanied by the increased presence of a diverse set of memory T cells, including central memory, effector memory and tissue-resident memory T cells. After the challenge, the T cell phenotype in the lymph nodes and lungs were characterized by a decrease in central memory T cells, and an increase in effector memory T cells and effector T cells. More importantly, when challenged 6 months after the immunization, this group demonstrated increased protection in comparison to BCG. In conclusion, this work provides experimental evidence in mice that the rBCG-LTAK63 vaccine induces a persistent increase in memory and effector T cell numbers until at least 6 months after immunization, which correlates with increased protection against Mtb. This improved immune response may contribute to enhance the long-term protection.

Intestinal Colonization of Campylobacter jejuni and Its Hepatic Dissemination Are Associated with Local and Systemic Immune Responses in Broiler Chickens.

Campylobacter jejuni is an important foodborne pathogen. Despite the lack of clinical signs associated with its colonization in poultry, it has been reported to interact with the intestinal immune system. However, little is known about the interaction between C. jejuni and the chicken immune system, especially in the context of hepatic dissemination. Therefore, to follow up on our previous study showing intestinal colonization and hepatic spread of C. jejuni, cecal tonsils and liver samples were collected from these birds to determine the mRNA levels of chemokines and cytokines. Serum samples were also collected to determine serum amyloid A (SAA) concentrations and specific IgY titers. Lack of Th17 induction was observed in the cecal tonsils of only the liver-contaminated groups. This hepatic dissemination was accompanied by innate, Th1 and Th2 immune responses in livers, as well as an increase in SAA concentrations and specific IgY levels in sera. Campylobacter appears to be able to restrain the induction of the chicken gut immunity in particular conditions, possibly enhancing its hepatic dissemination and thus eliciting systemic immune responses. Although Campylobacter is often recognized as a commensal-like bacterium in chickens, it seems to modulate the gut immune system and induce systemic immunity.

436 Nemolizumab monotherapy was associated with significant improvements in prurigo activity score in adult patients with moderate-to-severe prurigo nodularis: results from a phase 3 trial (OLYMPIA 2)

Abstract Prurigo nodularis (PN) or chronic nodular prurigo is a debilitating, and severely pruritic neuroimmune skin disease, predominantly characterized by the presence of multiple pruriginous nodules symmetrically distributed in large areas of the trunk and extremities. Other pruriginous lesions such as papules, plaques and umbilicated lesions can also be present. Prurigo nodularis dramatically reduces quality of life among patients, including disruption of physical, emotional and psychosocial domains. Therapeutic goals are primarily to reduce pruritus and improve lesion healing. Interleukin-31 (IL-31) is a neuroimmune cytokine highly expressed in PN lesional skin that bridges the immune and nervous systems, functioning as a central mediator of main pathophysiological processes in PN. Prurigo nodularis has a unique immunophenotype, with recent studies revealing activation of Type-2-inflammation, and also induction of Th17 and Th22 pathways. Nemolizumab, an IL-31 receptor alpha antagonist, was shown to downregulate these pathways and was associated with significant improvements in pruritus and lesion healing in patients with PN in a phase-2-trial. Here, the authors report additional outcomes on excoriations and healing of pruriginous lesions from the OLYMPIA 2 phase-3-study after 16 weeks of treatment with nemolizumab. This study aims to assess the safety and efficacy of nemolizumab compared with placebo in ≥18-year-old patients with moderate-to-severe PN after a 16-week treatment period. OLYMPIA 2 (NCT04501679) was a phase 3, global, multicenter, double-blind study in adults with PN presenting ≥20 nodules, Investigator’s Global Assessment (IGA) score ≥3 (range 0–4) and Peak Pruritus Numerical Rating Scale (PP-NRS) score ≥7.0 (range: 0–10). Patients were randomized (2 : 1) to receive nemolizumab (n = 183) or matching placebo (n = 91). Following an initial 60 mg loading dose, patients weighing <90 kg received 30 mg every 4 weeks (q4w) and those weighing ≥90 kg received 60 mg q4w, for a period of 16 weeks, during which, treatment with topical corticosteroids (TCS) or topical calcineurin inhibitors (TCI)was not allowed. The primary endpoints were proportion of patients with a ≥4-point improvement in weekly average PP-NRS and proportion of patients with IGA Success for nodule healing [score of 0 (clear) or 1 (almost clear) and a ≥2-grade improvement] at Week (W) 16. Key secondary endpoints included proportion of patients with ≥4-point improvement in PP-NRS at W4 and Sleep Disturbance NRS (SD-NRS) at W4 and W16. Other secondary endpoints included percentage of patients with pruriginous lesions with excoriations/crusts [Prurigo activity score (PAS) item 5a], healed pruriginous lesions (PAS item 5b) and <20 pruriginous lesions (PAS item 2) at each visit through W16. The baseline demographic and clinical characteristics were balanced between the groups. At W16, both primary endpoints, were met (P < 0.0001). A significantly higher proportion of patients in the nemolizumab-treated group vs. placebo-treated group achieved a ≥4-point improvement in weekly average PP-NRS score (56.3% vs. 20.9%) and IGA success (37.7% vs. 11.0%) at W16. The study also met all key secondary endpoints on pruritus and sleep disturbance (P < 0.0001). Among other secondary endpoints, a significantly higher proportion of patients in the nemolizumab-treated group vs. placebo-treated group achieved mild disease activity with ≤25% excoriations/crusts (PAS item 5a) (56.8% vs. 23.1%; P < 0.0001 at W16), >75% healed lesions (PAS item 5b) (55.2% vs. 16.5%; P < 0.0001 at W16) and <20 pruriginous lesions (PAS item 2) (54.6% vs. 22.0%; P < 0.0001 at W16) at each visit, from baseline through W16. Treatment-emergent adverse events (AEs) were reported in 61.2% of nemolizumab-treated patients and 52.7% of placebo-treated patients, while serious AEs were reported in 2.2% of nemolizumab-treated patients and 5.5% of placebo-treated patients. Nemolizumab monotherapy (without TCS or TCI) demonstrated a significant reduction of pruritus as well as excoriations and number of pruriginous lesions after 16 weeks of treatment in patients with moderate-to-severe PN. The safety profile was consistent with that previously observed.

TRAF6 signaling in dendritic cells plays protective role against infectious colitis by limiting C. rodentium infection through the induction of Th1 and Th17 responses

Tumor necrosis factor receptor-associated factor 6 (TRAF6) plays a pivotal role in the induction of inflammatory responses not only in innate immune cells but also in non-immune cells, leading to the activation of adaptive immunity. Signal transduction mediated by TRAF6, along with its upstream molecule MyD88 in intestinal epithelial cells (IECs) is crucial for the maintenance of mucosal homeostasis following inflammatory insult. The IEC-specific TRAF6-deficient (TRAF6ΔIEC) and MyD88-deficient (MyD88ΔIEC) mice exhibit increased susceptibility to DSS-induced colitis, emphasizing the critical role of this pathway. Moreover, MyD88 also plays a protective role in Citrobacter rodentium (C. rodentium) infection-induced colitis. However, its pathological role of TRAF6 in infectious colitis remains unclear. To investigate the site-specific roles of TRAF6 in response to enteric bacterial pathogens, we infected TRAF6ΔIEC and dendritic cell (DC)-specific TRAF6-deficient (TRAF6ΔDC) mice with C. rodentium and found that the pathology of infectious colitis was exacerbated with significantly decreased survival rates in TRAF6ΔDC mice, but not in TRAF6ΔIEC mice, compared to those in control mice. TRAF6ΔDC mice showed increased bacterial burdens, marked disruption of epithelial and mucosal structures with increased infiltration of neutrophils and macrophages, and elevated cytokine levels in the colon at the late stages of infection. The frequencies of IFN-γ producing Th1 cells and IL-17A producing Th17 cells in the colonic lamina propria were significantly reduced in TRAF6ΔDC mice. Finally, we demonstrated that TRAF6-deficient DCs failed to produce IL-12 and IL-23 in response to C. rodentium stimulation, and to induce both Th1 and Th17 cells in vitro. Thus, TRAF6 signaling in DCs, but not in IECs, protects against colitis induced by C. rodentium infection by producing IL-12 and IL-23 that induce Th1 and Th17 responses in the gut.

T cell-intrinsic C5L2 activation protects against uncontrolled inflammatory Th responses and autoimmunity

Abstract Intracellular/autocrine complement proteins have emerged as critical regulators of human Th1 induction and contraction. T cells contain both intracellular C3 and C5 activation systems, with intracellular C3aR1 and C5aR1 stimulation driving T cell homeostatic survival and normal Th1 IFNg production, respectively. Here we demonstrate how the intracellular/autocrine C5 system is regulated by using T cells from the first described patient with C5aR2 deficiency. This patient suffers from an autoinflammatory syndrome, with enhanced inflammatory Th responses and a profound loss of naïve CD4 T cells in the blood (95% have a memory phenotype). Thus, in contrast to intracellular C5aR1 stimulation, cell surface expressed C5aR2 is an important negative regulator of inflammatory Th induction. While both C5aR1 and C5aR2 can bind C5a, we found that the carboxypeptidase-processed form of C5a, C5a-desArg, was twice as potent as C5a in reducing Th1 induction. In addition, carboxypeptidase M (CPM) expression was highly induced upon T cell activation indicating that CPM may be mediating T cell-derived C5a-desArg generation and C5aR2 stimulation. In this vein, activation of CRISPR/Cas9 generated CPMKO T cells, or of T cells in the presence of a CPM inhibitor, induced Th1 hyper-induction, which was rescued by addition of a C5aR2 agonist and reduced by adding C5a-desArg, but not C5a. The in vivo importance of T cell-expressed CPM and autocrine C5aR2 activation is demonstrated by the enhanced inflammatory Th responses in Cpm −/−mice and increased pathology caused by Cpm −/−T cells in a T cell transfer colitis model. These data highlight the importance of intracellular/autocrine C5 system regulation by CPM through C5aR2 signaling in T cell responses.

BLOC1S1: An Unexpected Regulator of Th2 Cell-driven Inflammatory Responses

Abstract BLOC1S1 is an adaptor protein that modulates endosome-lysosome function as a component of numerous multiprotein complexes. We postulated that its modulation in CD4 +T cells may help us uncover the role of endosome-lysosome biology in adaptive immunity. In primary CD4 +T cells BLOC1S1 cre-recombinase knockout resulted in the preferential induction of Th2 compared to Th1 and Th17 cytokine production following T cell receptor activation. As atopic dermatitis is an allergic inflammatory skin disease characterized by the production of the type 2 cytokines in the skin we evaluated the effect of CD4 +T cell BLOC1S1 KO vs controls in calcipotriol-induced atopic dermatitis in mice. The absence of BLOC1S1 exhibited exacerbated atopic dermatitis accompanied with significantly elevated plasma IgE, skin eosinophilia, elevated type 2 responses, and inflammatory pathology relative to wild-type mice. The transcription factor Gata-3 is expressed in Th2 but not Th1 cells and plays a critical role in Th2 differentiation and atopic dermatitis. BLOC1S1 deficient CD4 +T cells showed enhanced nuclear factor kB (NF-kB), Gata3 and LC3 positive autophagosomes. Inhibition of NF-kB activity prevented Gata-3 expression, LC3 positive autophagosomes and Th2 cytokine production in BLOC1S1 −/− CD4 +T cells. This mouse model will now give us a platform to explore the role of endo-lysosomal biology in Th2 polarization and activation. NHLBI Division of Intramural Research (MNS-ZIA-HL005102)