Clinical and experimental immunology最新文献

Neutrophils are key effector leukocytes of the innate immune system and play a pivotal role in defending the host against microbial infections. Recent studies have identified a crucial link between glycolysis and neutrophil cellular functions. Using human neutrophils, we have investigated the intricate relationship between glycolysis, extracellular glucose availability, and the enzyme 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), in the regulation of reactive oxygen species (ROS) and neutrophil extracellular trap (NET) production. We have identified that PFKFB3 is elevated in rheumatoid arthritis (RA) neutrophils and that the small molecule PFKFB3 inhibitor 3PO is a key regulator of neutrophil ROS and NET production. 3PO blocked the production of ROS and NETs in a dose-dependent manner in both RA and healthy (HC) neutrophils (p<0.01), and RA neutrophils were more sensitive to lower concentrations of 3PO. Bacterial killing was only partially inhibited by 3PO, and the proportion of live neutrophils after 24h incubation was unchanged. Using NMR metabolomics, we identified that 3PO increases the concentration of lactate, phenylalanine and L-glutamine in neutrophils, as well as significantly decreasing intracellular glutathione (adj. p-value<0.05). We also demonstrated that RA neutrophils produce ROS and NETs in culture conditions which mimic the low glucose environments encountered in RA synovial joints. Our results also suggest 3PO may have molecular targets beyond PFKFB3. By dissecting the intricate interplay between metabolism and neutrophil effector functions, this study advances the understanding of the molecular mechanisms governing pro-inflammatory neutrophil responses and identifies 3PO as a potential therapeutic for conditions characterized by dysregulated neutrophil activation.

T cell receptor (TCR) signalling is crucial in determining the fate of thymocyte differentiation in the thymus. The high-avidity interaction between TCR and self-peptide-MHC complexes induces development of regulatory T cells (Tregs), lineage commitment for which is controlled by expression of transcription factor Forkhead box P3 (FoxP3) . The non-catalytic region of the tyrosine kinase (Nck) comprises two members, Nck1 and Nck2, with Nck1 playing a dominant role in TCR-mediated T-cell activation and function. Nck's role, while established in thymocyte development, remains unelucidated in development of Tregs. In this study, we aimed to determine the function of Nck1 in the in vitro development and differentiation of human thymocytes. Human thymocytes were transfected with shRNA plasmid to silence Nck1 expression. The number of FoxP3+ Tregs decreased noticeably in Nck1 knockdown thymocytes after co-cultivation with myeloid dendritic cells (mDCs) and thymic epithelial cells (TECs) for 14 days. Furthermore, decreased phosphorylation of AKT and FoxO1 was observed in Nck1-silenced thymocytes, in association with reduced FoxO1 nuclear localisation. Taken together, these findings identify the pivotal role of Nck1 in Treg development.

Interleukin-1β (IL-1β) is a key mediator of innate immunity against pathogen infections. However, dysregulated IL-1β activity is associated with various autoinflammatory, autoimmune, degenerative, atherosclerotic diseases, and cancers. Biologic drugs that neutralize excess IL-1β activity, such as canakinumab, have been effective in treating IL-1β-mediated diseases. This article reports the discovery and development of a novel humanized anti-IL-1β antibody, designated as TAVO103A, which exhibited potent binding affinities to human and monkey IL-1β. TAVO103A demonstrated more potent neutralization of IL-1β activities compared to canakinumab in multiple assays, including tests on the IL-1β-driven signal transduction cascade, inflammatory cytokine release from MRC-5 cells, chemokine release from A549 cells, and the proliferation of D10.G4.1 helper T cells. Ex vivo studies showed that TAVO103A effectively neutralized IL-1β-mediated release of pro-inflammatory cytokines from peripheral blood mononuclear cells (PBMC). In addition, TAVO103A exhibited dose-dependent efficacy in a knee joint inflammation mouse model. TAVO103A underwent Fc engineering to reduce binding to Fcγ receptors, increase affinity to FcRn receptors, and enhance its resistance to proteolytic degradation. In a Phase 1 study, TAVO103A was found to be safe, well tolerated, and demonstrated a median half-life of 63 days in healthy subjects. By recognizing a different epitope, TAVO103A provided more potent neutralization of IL-1β activities, a longer circulating half-life, and improved safety profiles compared to canakinumab, positioning it to be a potential best-in-class therapeutic option for various IL-1β-mediated diseases.

Adoptive cell therapy (ACT) with ex-vivo expanded tumor-infiltrating lymphocytes (TILs, TIL-ACT) has shown clinical efficacy in a significant proportion of patients with metastatic melanoma. To further target TIL-ACT towards responsive patients, identifying predictive biomarkers and understanding broader immune dynamics remain critical. This study investigated the peripheral blood immune landscape in 47 patients with metastatic melanoma undergoing TIL-ACT, assessing antitumor reactivity and peripheral immune cell profiles before and after treatment. Responders displayed increased frequency of circulating tumor-reactive cells post-treatment, and higher baseline levels of activated CD57-expressing T cells, serving as potential biomarkers of response. In contrast, persistent high serum levels of interleukin (IL)-6 and IL-8, higher frequencies of CD38-expressing T cells and regulatory T cells (Tregs) post-treatment, correlated with unfavorable outcomes. These findings contribute to understanding of the peripheral immune landscape associated with response to TIL-ACT, offering valuable insights into predictive biomarkers and mechanisms to improve patient selection.

Introduction: Despite the high global prevalence of Mycobacterium tuberculosis (Mtb) infection in humans, most infected individuals achieve a stable immunological equilibrium, without showing clinical signs and symptoms of tuberculosis (TB). Although the role of antibodies in TB is assumed to be relatively small compared to cell-mediated immunity, their role in TB has been documented in a few recent studies.

Methods: In this cross-sectional study, we quantitated antibody responses to Mtb antigens, lipoarabinomannan (LAM), and heparin-binding hemagglutinin adhesin (HBHA) by determining antigen-specific immunoglobulin A(IgA) and G(IgG) secretion levels using enzyme-linked immunosorbent assay (ELISA) in serum and saliva of pulmonary TB patients (PTB), their household contacts (HHC), and community controls (CC) (determined by QuantiFERON TB Gold assay QFT- test result).

Results: The HBHA-specific IgA levels were significantly higher in both saliva and serum in HHC groups compared to PTB patients (P=0.013, P=0.023). Exposed contacts, who were QFT-negative had higher serum HBHA-specific IgA responses compared to PTB patients (P=0.04). QFT-negative HHC and QFT-positive CC showed higher HBHA and LAM-specific IgG responses (P=0.006, P=0.002, P=0.0009, P=0.006, respectively) than PTB patients. Generally, LAM and HBHA-specific IgA levels were significantly higher in saliva compared to serum (P<0.0001) in all study groups.

Conclusion: Overall, the observed higher levels of IgA and IgG in controls, and exposed but QFT-negative contacts suggest a correlation with, and perhaps a role for these antibodies in preventing the development of active TB. The findings highlighted the potential involvement of saliva IgA in the immune response to Mtb, underscoring the relevance of mucosal immunity in TB infection.

Objective: To investigate whether T-bet+ B cells, as well as age-associated B cells/ABCs (CD19+CD21-CD11c+T-bet+) and double-negative B cells/DN (CD19+IgD-CD27- CXCR5-T-bet+), serve as prognostic and/or therapeutic tools for systemic lupus erythematosus (SLE) in humans.

Methods: Flow cytometry was used for enumerating T-bet+ B cells and ABCs/DN subsets, found in the peripheral blood of 10 healthy donors and 22 active SLE patients. Whole blood assay cultures, combined with in vitro pharmacological treatments, were performed to evaluate the effects of hydroxychloroquine, anifrolumab and fasudil (a ROCK kinase inhibitor) on T-bet+ B cells' percentage. Moreover, previously published single-cell RNA sequencing (scRNA-seq) data were used in a meta-analysis to allow characterization of genes and pathways associated with the biology of T-bet in B cells.

Results: T-bet+ B cells displayed an expansion in SLE patients [1.47 (1.9 - 0.7) vs 10.85 (37.4 - 3.6)]. Similarly, both ABCs and DN were found to be expanded. Interestingly, percentages of T-bet+ B cells positively correlated with patients' SLEDAI scores (rs=0.55, p=0.007). Cell culture experiments conducted, revealed that all three agents tested can deplete T-bet+ B cells (without affecting the cell viability of lymphocytes, T cells and B cells). According to bioinformatics analyses, T-bet is highly expressed in two B cell clusters with pathogenic characteristics for SLE (designated as atypical memory B cells and activated naïve B cells). These clusters can be targeted for therapeutic interventions.

Conclusions: T-bet+ B cells can serve as a putative prognostic biomarker of lupus severity. Circumstantial data suggest that these cells may promote disease pathogenesis and may represent a novel therapeutic target.

Introduction: Increasing evidence supports the involvement of inborn errors of immunity (IEI) in severe infections, but little is known about the prevalence of these genetic defects in children with sepsis. Due to the limited understanding of the molecular and immunological mechanisms driving sepsis, genetic testing is rarely used in routine diagnostics to identify genetic susceptibility to the condition.

Methods: We performed a prospective observational study on previously healthy children hospitalized for severe infections, including sepsis. Patients underwent immunophenotyping and whole-exome sequencing (WES), followed by in silico analysis to identify potentially causal variants. We assembled a cohort of 194 previously healthy children, including 149 (77%) patients with severe infection and 45 (23%) with sepsis. Our cohort was marked by a high frequency of respiratory tract infections (35%), bloodstream infections (20%), and central nervous system infections (16%).

Results: The genetic investigation identified 28 potentially causal variants, 18 (64%) are classified as variants with uncertain significance, and 10 (36%) are likely pathogenic variants. Of 45 patients with sepsis, 6 (13%) had potentially causal genetic variants. Similarly, 22/149 (15%) patients with severe infection presented potentially causal genetic variants. WES predicted the impairment of various immune mechanistic pathways such as immune dysregulation defects, antibody deficiencies, and combined immunodeficiencies (18% each).

Conclusion: We found no clear association between genetic variants and the studied parameters: organ failure, microbe identification, immunoglobulin levels, and lymphocyte subset numbers. Although WES is a valuable tool for detecting IEI underlying sepsis and unexplained severe infections, it could be selectively recommended for patients with a strong clinical suspicion of genetic abnormalities, balancing its diagnostic value with its cost and complexity.

Large scale population studies are important to monitor and evaluate aspects of a vaccination programme including vaccine coverage, real-world effectiveness, and post-licensure vaccine safety. These types of epidemiological studies often come under the remit of public health agencies, such as the UK Health Security Agency (UKHSA) in England, who are required to undertake surveillance of vaccine preventable diseases, including via seroepidemiological studies and data linkage studies using national level electronic healthcare data. An individual level national vaccine register with an accurate denominator can be the key to gaining insights into vaccine coverage, effectiveness and safety. During the COVID-19 pandemic, England's first vaccine register was developed. This enabled timely estimates of real-world vaccine effectiveness in the whole population of England, as well as enabling epidemiological investigations of rare potential risks from vaccines in specific populations. Population-based research studies, including prospective cohort studies are complementary to surveillance, and combined, enable more comprehensive assessments. As there was unprecedented investment into research studies and infrastructure during the pandemic, the scale of these studies meant they were able to contribute to vaccine programme evaluations in a way that had not been possible for previous vaccine programmes. In this review, we summarise the different large scale surveillance and research studies that have been used to evaluate and inform vaccine policy from the time of the first data linkage studies undertaken in England in the 1990s to the present day post-COVID-19 pandemic.

T cells are one of the main drivers of inflammatory bowel diseases (IBD). Infliximab (IFX) is used in the treatment of IBD as an anti-inflammatory drug to induce remission by neutralizing TNFα. We determined the individual chemokine/homing receptor and cytokine profile in pediatric IBD patients before and during IFX therapy to identify predictive biomarkers for therapy success. Peripheral blood CD4+ cells from pediatric patients with IBD were immunomagnetically isolated and either directly analyzed by FACS for cell distribution and chemokine/homing receptor expression or evaluated for cytokine production after in-vitro-stimulation. Twenty-one responders (RS) and 21 non-responders (NRS) were recruited. Before IFX therapy, flow cytometry revealed decreased percentages of naïve conventional T cells in pediatric IBD patients. The proportions of CD62-L+ T cells were decreased in both CD and UC therapy responders. The cytokine profile of T cells was highly altered in IBD patients compared to healthy controls (HC). During IFX therapy, the frequencies of conventional memory and regulatory memory T cells expanded in both cohorts. IFX response was marked by a decrease of α4β7+ and IFNγ+ memory T cells in both CD and UC. In contrast, frequencies of Lag-3+ T cells proved to be significantly increased in NRS. These observations were irrespective of the underlying disease. T cells of pediatric IBD patients display an activated and rather Th1/Th17-shifted phenotype. The increased expression of the checkpoint molecule Lag-3 on T cells of NRS resembles a more exhausted phenotype than in RS and HC which appeared to be a relevant predictive marker for therapy failure.