Immunology最新文献

Among several quantitative trait loci involved in tuberculosis (TB) control in mice, one was mapped within the chromosome 17 segment occupied by the H2 complex and another within the chromosome 3 segment comprising the S100A8/9 genes, which encode neutrophil inflammatory factor S100A8/9. Previously, we developed a panel of H2-congenic mouse strains differing by small segments of the major histocompatibility complex Class II (MHC-II) region from TB-susceptible H2^j mice transferred onto the genetic background of the TB-resistant C57BL/6 (H2^b) strain. Susceptible B6.I-9.3 mice differ from B6 progenitors by the alleles of their only classical MHC-II H2-Aβ gene. The goals of the present study were to: (i) comprehensively characterise the differences in TB-related phenotypes between mice of the two strains and (ii) decipher interactions between the H2-Aβ and S100A8/9 genes. Here, we describe the dynamics of TB-related phenotypes differentiating B6.I-9.3 and B6 mice (colony forming units counts, histopathology, lung immune cell infiltration and cytokine profiles). We show that disproportionally diminished CD4⁺ T-cell population, an enlarged S100A8/9-positive neutrophil population and higher S100A8/9 serum levels in B6.I-9.3 mice collectively form the ‘susceptible’ phenotype before infection. An increase in IL-17 and a decrease in intrferon-gamma production by CD4⁺ T-cells in these mice provide a mechanistic explanation of this phenotype. Using F2 segregation analysis, we show that the number of S100A8/9-producing neutrophils in lungs and spleens and the proportion of Th17 CD4⁺ T-cells in lungs are significantly lower in the presence of the MHC-II dominant ‘resistant’ b allele compared to the recessive ‘susceptible’ j/j genotype. This provides direct genetic evidence that MHC-II-regulated CD4⁺ T-cell landscapes determine neutrophil abundance before infection, an important pathogenic factor in TB immunity.

The adverse effects observed in some cancer patients treated with erythropoiesis-stimulating agents such as erythropoietin (EPO) might be due to the latter's well-known immunosuppressive functions. Here, we used a mouse model of syngeneic triple-negative breast cancer to explore EPO's immunomodulatory role in a tumour setting. Our results showed that EPO treatment promotes tumour growth, exacerbates the ‘immune desert’, and results in a ‘cold tumour’. EPO treatment changed the immune cell distribution in peripheral blood, secondary lymphoid organs, and the tumour microenvironment (TME). Our in-depth analysis showed that EPO mainly impacts CD4 T cells by accelerating their activation in the spleen and thus their subsequent exhaustion in the TME. This process is accompanied by a general elevation of CD39 expression by several immune cells (notably CD4 T cells in the tumour and spleen), which promotes an immunosuppressive TME. Lastly, we identified a highly immunosuppressive CD39⁺ regulatory T cell population (ICOS⁺, CTLA4⁺, Ki67⁺) as a potential biomarker of the risk of EPO-induced tumour progression. EPO displays pleiotropic immunosuppressive functions and enhances mammary tumour progression in mice.

Targeting immune receptors on T cells is a common strategy to treat cancer and autoimmunity. Frequently, this is accomplished through monoclonal antibodies targeting the ligand binding sites of stimulatory or inhibitory co-receptors. Blocking ligand binding prevents downstream signalling and modulates specific T cell functions. Since 1985, the FDA has approved over 100 monoclonal antibodies against immune receptors. This therapeutic approach significantly improved the care of patients with numerous immune-related conditions; however, many patients are unresponsive, and some develop immune-related adverse events. One reason for that is the lack of consideration for the localization of these receptors on the cell surface of the immune cells in the context of the immune synapse. In addition to blocking ligand binding, changing the location of these receptors on the cell surface within the different compartments of the immunological synapse could serve as an alternative, efficient, and safer approach to treating these patients. This review discusses the potential therapeutic advantages of altering proteins' localization within the immune synapse and summarizes published work in this field. It also discusses the novel use of bispecific antibodies to induce the clustering of receptors on the cell surface. It presents the rationale for developing novel antibodies, targeting the organization of signalling receptor complexes on the cell surface. This approach offers an innovative and emerging technology to treat cancer patients resistant to current immunotherapies.

Maintaining intracellular redox balance is essential for the survival, antibody secretion, and mucosal immune homeostasis of immunoglobulin A (IgA) antibody-secreting cells (ASCs). However, the relationship between mitochondrial metabolic enzymes and the redox balance in ASCs has yet to be comprehensively studied. Our study unveils the pivotal role of mitochondrial enzyme PCK2 in regulating ASCs' redox balance and intestinal homeostasis. We discover that PCK2 loss, whether globally or in B cells, exacerbates dextran sodium sulphate (DSS)-induced colitis due to increased IgA ASC cell death and diminished antibody production. Mechanistically, the absence of PCK2 diverts glutamine into the TCA cycle, leading to heightened TCA flux and excessive mitochondrial reactive oxygen species (mtROS) production. In addition, PCK2 loss reduces glutamine availability for glutathione (GSH) synthesis, resulting in a decrease of total glutathione level. The elevated mtROS and reduced GSH expose ASCs to overwhelming oxidative stress, culminating in cell apoptosis. Crucially, we found that the mitochondria-targeted antioxidant Mitoquinone (Mito-Q) can mitigate the detrimental effects of PCK2 deficiency in IgA ASCs, thereby alleviating colitis in mice. Our findings highlight PCK2 as a key player in IgA ASC survival and provide a potential new target for colitis treatment.

Intermittent fasting (IF) refers to periodic fasting routines, that caloric intake is minimized not by meal portion size reduction but by intermittently eliminating ingestion of one or several consecutive meals. IF can instigate comprehensive and multifaceted alterations in energy metabolism, these metabolic channels may aboundingly function as primordial mechanisms that interface with the immune system, instigating intricate immune transformations. This review delivers a comprehensive understanding of IF, paying particular attention to its influence on the immune system, thus seeking to bridge these two research domains. We explore how IF effects lipid metabolism, hormonal levels, circadian rhythm, autophagy, oxidative stress, gut microbiota, and intestinal barrier integrity, and conjecture about the mechanisms orchestrating the intersect between these factors and the immune system. Moreover, the review includes research findings on the implications of IF on the immune system and patients burdened with autoimmune diseases.

Liu X, Xu X, Liao Y, Yao W, Geng X, Zeng X, et al. Psychological stress to ovalbumin peptide-specific T-cell receptor transgenic mice impairs the suppressive ability of type 1 regulatory T cell. Immunology. 2024;172(2):210–25. https://doi.org/10.1111/imm.13767.

Authors checked the data of the paper recently and found that Figure 2b is unnecessary. While the old Figure 2b describes a portion of the same data, which are described in Figure 2a. It is unnecessary to repeatedly present these data. Thus, authors removed the old Figure 2b from fig. 1._

We apologise for this error.

The explicit identification of CD8⁺ T cell subpopulation is important for deciphering the role of CD8⁺ T cells for protecting our body against invading pathogens and cancer. Our generated monoclonal antibody (mAb), named FE-1H10, recognized two novel subpopulations of peripheral blood CD8⁺ T cells, FE-1H10⁺ and FE-1H10⁻ CD8⁺ T cells. The molecule recognized by mAb FE-1H10 (FE-1H10 molecules) had a higher distribution on effector memory CD8⁺ T cell subsets. The functions of FE-1H10⁻ and FE-1H10⁺ CD8⁺ T cells were investigated. T cell proliferation assays revealed that FE-1H10⁻ CD8⁺ T cells exhibited a higher proliferation rate than FE-1H10⁺ CD8⁺ T cells, whereas FE-1H10⁺ CD8⁺ T cells produced higher levels of IFN-γ and TNF-α than FE-1H10⁻ CD8⁺ T cells. In T cell cytotoxicity assays, FE-1H10⁺ CD8⁺ T cells were able to kill target cells better than FE-1H10⁻ CD8⁺ T cells. RNA-sequencing analysis confirmed that these subpopulations were distinct: FE-1H10⁺ CD8⁺ T cells have higher expression of genes involved in effector functions (IFNG, TNF, GZMB, PRF1, GNLY, FASL, CX3CR1) while FE-1H10⁻ CD8⁺ T cells have greater expression of genes related to memory CD8⁺ T cell populations (CCR7, SELL, TCF7, CD40LG). The results suggested that mAb FE-1H10 identifies two novel distinctive CD8⁺ T cell subpopulations. The FE-1H10⁺ CD8⁺ T cells carried a superior functionality in response to tumour cells. The uncover of these novel CD8⁺ T cell subpopulations may be the basis knowledge of an optional immunotherapy for the selection of potential CD8⁺ T cells in cancer treatment.

Expansion of CD4⁺CD28^null T-lymphocytes is common in chronic heart failure (CHF) patients. Its ability to produce high levels of proinflammatory cytokines is probably the key role of these cells in CHF. IL-10 is a candidate for limiting CD4⁺CD28^null T-lymphocyte responses, whereas tumour necrosis factor (TNF) is the cytokine most closely involved in the loss of CD28 expression. Serum levels of TNF and IL-10 were measured in 65 CHF patients (mean age, 65.2 ± 13.84 years). Patients with an IL-10/TNF ratio ≥1 had significantly lower levels of CD4⁺CD28^null T-lymphocytes than those with a ratio <1. In vitro, IL-10 reduced the frequency of proliferative CD4⁺CD28^null T-lymphocytes stimulated with anti-CD3. Pre-treatment with IL-10 before anti-CD3 stimulation was required for the cytokine to inhibit TNF production by CD4⁺CD28^null T-lymphocytes. In addition to the previously described effect of IL-10 on HLA-DR and ICAM-1 expression, LFA-3 protein and mRNA levels were reduced in the presence of the cytokine in monocytes. IL-10 inhibition on CD4⁺CD28^null T-lymphocytes may be mediated by a reduction in HLA class II and LFA-3 expression because blocking interactions with these costimulators has similar effects to those of IL-10 treatment. Moreover, costimulation through CD2/LFA-3 interaction is enough to induce proliferation and cytokine production in CD4⁺CD28^null T-lymphocytes.

Tuberculosis (TB) alone caused over a billion deaths in the last 200 years, making it one of the deadliest diseases to humankind. Understanding the immune mechanisms underlying protection or pathology in TB is key to uncover the much needed innovative approaches to tackle TB. The scavenger receptor cysteine-rich molecule CD5 antigen-like (CD5L) has been associated with TB, but whether and how CD5L shapes the immune response during the course of disease remains poorly understood. Here, we show an upregulation of CD5L in circulation and at the site of infection in C57BL/6 Mycobacterium tuberculosis-infected mice. To investigate the role of CD5L in TB, we studied the progression of M. tuberculosis aerosol infection in a recently described genetically engineered mouse model lacking CD5L. Despite the increase of CD5L during infection of wild-type mice, absence of CD5L did not impact bacterial burden, histopathology or survival of infected mice. Absence of CD5L associated with a modest increase in the numbers of CD4+ T cells and the expression of IFN-γ in the lungs of infected mice, with no major effect in overall immune cell dynamics. Collectively, this study confirms CD5L as a potential diagnostic biomarker to TB, showing no discernible impact on the outcome of the infection.

The activation of CD4+ T-cells in a T cell receptor (TCR)-dependent antigen-specific manner is a central characteristic of the adaptive immune response. In addition to ensuring that CD4+ T-cells recognise their cognate antigen during activation, TCR-mediated signalling can also direct the outcome of differentiation. In both in vivo and in vitro model systems, strong TCR signalling has been demonstrated to drive Th1 differentiation, whereas weak TCR signalling drives Th2 responses. During the process of differentiation, TCR signal strength acts as a quantitative component in combination with the qualitative effects imparted by cytokines to polarise distinct T-helper lineages. Here, we investigated the role of interleukin 2 (IL-2) signalling in determining the outcome of TCR-dependent differentiation. IL-2 production was initiated as an early response to TCR-induced activation and was regulated by the strength of TCR signalling initially received. In the absence of IL-2, TCR dependent differentiation was found to be abolished. However, proliferative responses and early markers of activation were maintained, including the upregulation of GATA3, Tbet and Foxp3 at 24 h post-stimulation. Demonstrating that IL-2 signalling has a key role in stabilising and amplifying lineage-specific transcirption factor expression during differentiation. Further, activation of IL-2-deficient T-cells in the presence of exogenous cytokines was sufficient to restore differentiation whilst maintaining transcriptional signatures imparted during initial TCR signalling. Combined, our data demonstrate that the integration of quantitative TCR-dependent signalling and qualitative IL-2 signalling is essential for determining the fate of CD4+ T-cells during differentiation.