Journal of immunology最新文献

Natural killer (NK) cells can efficiently mediate antibody-dependent cellular cytotoxicity (ADCC) of antibody coated target cells via the low-affinity Fc-receptor, CD16, but cannot retain antibodies over time. To increase antibody retention and facilitate targeted ADCC, we genetically modified human NK cells with the high-affinity Fc receptor, CD64, so that we could preload them with HIV-specific broadly neutralizing antibodies (BNAbs) and enhance their capacity to target HIV-infected cells via ADCC. Purified NK cells from the peripheral blood of control donors or persons living with HIV were activated with interleukin (IL)-2/IL-15/IL-21 cytokines and transduced with a lentivirus encoding CD64. High levels of CD64 surface expression were maintained for multiple weeks on NK cells and CD64-transduced NK cells were phenotypically similar to control NK cells with strong expression of CD56, CD16, NKG2A, NKp46, CD69, HLA-DR, CD38, and CD57. CD64-transduced NK cells exhibited significantly greater capacity to bind HIV-specific BNAbs in short-term antibody binding assay as well as retain the BNAbs over time (1-wk antibody retention assay) compared with control NK cells only expressing CD16. BNAb-preloaded CD64-transduced NK cells showed a significantly enhanced capacity to mediate ADCC against autologous HIV-1-infected CD4+ primary T cells in both a short-term 4 h degranulation assay as well as a 24 h HIV p24 HIV elimination assay when compared with control NK cells. A chimeric CD64 enhanced NK cell strategy (NuKEs [NK Enhancement Strategy]) retaining bound HIV-specific BNAbs represents a novel autologous primary NK cell immunotherapy strategy against HIV through targeted ADCC.

A fundamental dichotomy in lymphocytes separates adaptive T and B lymphocytes, with clonally expressed antigen receptors, from innate lymphocytes, which carry out more rapid responses. Some T cell populations, however, are intermediates between these 2 poles, with the capacity to respond rapidly through T cell receptor activation or by cytokine stimulation. Here, using publicly available datasets, we constructed linear mixed models that not only define a gradient of innate gene expression in common for mouse innate-like T cells, but also are applicable to other mouse T lymphoid populations. A similar gradient could be identified for chromatin landscape based on ATAC-seq (assay for transposase-accessible chromatin using sequencing) data. The gradient included increased transcripts related to many traits of innate immune responses, with increased scores related to evidence for antigen experience. While including genes typical for T helper 1 (Th1) responses, the innateness gene program could be separated from Th1, Th2, and Th17 responses. Lymphocyte populations with higher innateness scores correlated with lower calcium-dependent T cell receptor-mediated cell activation, with some downstream signaling proteins dependent on calcium or affecting metabolism prephosphorylation. Therefore, as a group, different mouse innate-like T cell populations had related gene expression programs and activation pathways that are different from naive CD4 and CD8 T cells.

Several vaccines and immunization strategies, including inactivated vaccines, have proven effective in eliciting antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), providing an opportunity to characterize the antibody response. In this study, we investigated the monoclonal antibody responses elicited by wild-type SARS-CoV-2 inactivated vaccination compared to those elicited by natural infection and mRNA vaccination. The analysis showed that antibodies encoded by biased germline genes were shared between SARS-CoV-2 vaccinated and naturally infected individuals. Among the 35 shared clonotypes identified, besides the well-known IGHV3-53 and IGHV1-58, we identified a class of IGHV4-59 antibodies characterized by rapid response and neutralizing activity, elicited by 3 doses of inactivated vaccine. Members of this lineage exhibited similar sensitivity against wild-type SARS-CoV-2, whereas different neutralizing activities against SARS-CoV-2 variants, especially against various Omicron subvariants, BA.1, BA.2, BA.2.12.1, BA.4/5, and BA.2.75. Structural analysis of BA.1 spike complexed with VacBB-639 revealed that the IGHV4-59-lineage antibodies belonged to the Class 2/3 group. Using sequence alignment, site-mutation assays, and functional verification, we identified two substitutions, N60K in HFR3 and S56G in HCDR2, contributing to opposite neutralization changes of IGHV4-59-lineage antibodies against these Omicron subvariants. These results demonstrate the importance of somatic hypermutation in the evolution of prototypical antigen-elicited antibodies in terms of their neutralization breadth and potency against SARS-CoV-2 Omicron variants.

Mitochondrial antiviral-signaling protein (MAVS) is a key adapter protein required for inducing type I interferons (IFN-Is) and other antiviral effector molecules. The formation of MAVS aggregates on mitochondria is essential for its activation; however, the regulatory mitochondrial factor that mediates the aggregation process is unknown. Our recent work has identified the protein Aggregatin as a critical seeding factor for β-amyloid peptide aggregation. Here we show that Aggregatin serves as a cross-seed for MAVS aggregates on mitochondria to orchestrate innate immune signaling. Aggregatin is primarily localized to mitochondria in the cytosol and has the ability to induce MAVS aggregation and MAVS-dependent IFN-I responses alone in both HEK293 cells and human leukemia monocytic THP-1 cells. Mitochondrial Aggregatin level increases upon viral infection. Also, Aggregatin knockout suppresses viral infection-induced MAVS aggregation and IFN-I signal cascade activation. Nemo-like kinase is further identified as a kinase phosphorylating Aggregatin at Ser59 to regulate its stability and cross-seeding activity. Collectively, our finding reveals an important physiological function of Aggregatin in innate immunity by cross-seeding MAVS aggregation.

Diabetic nephropathy is a severe chronic complication characterized by cytotoxicity, inflammation, and fibrosis, ultimately leading to renal failure. This study systematically investigated the effects of the PARP1 inhibitor PJ-34 on high glucose-induced cytotoxicity, inflammation, and fibrosis in HK-2 cells, as well as its improvement on neuropathic pain response and transforming growth factor β (TGFβ) expression in a type 1 diabetes mellitus diabetic nephropathy mouse model. Through cellular and animal experiments, we observed that PJ-34 significantly enhanced the proliferative capacity of cells damaged by high glucose, reduced apoptosis, and decreased the release of proinflammatory factors TGFα, interleukin-6, and interleukin-1β. In the type 1 diabetes mellitus nephropathy mouse model, the administration of PJ-34 substantially improved parameters of neuropathic pain, alleviated renal tissue damage, reduced indicators of renal functional impairment-inhibited renal fibrosis, and reduced the key protein expression in the epithelial-mesenchymal transition process, acting through the regulation of the TGFβ/Smads signaling pathway. This study elucidated the mechanism of action of the PARP1 inhibitor PJ-34 as a potential therapeutic agent for diabetic nephropathy, offering a novel strategy for its treatment.

Ammonia fertilizer, primarily composed of ammonium chloride, is widely used in pond fish farming throughout Asia. Despite the belief that it possesses antiviral properties, the underlying mechanisms remain unclear. Ammonium chloride (NH4Cl) has been demonstrated to act as a potent inhibitor of autophagy, which is used by many fish viruses to promote their proliferation during infection. It was therefore hypothesized that the antiviral effect of ammonia fertilizers was likely due to the inhibition of autophagy in viruses. The present study sought to evaluate the antiviral effect of NH4Cl in a model of several fish cells and zebrafish. The findings demonstrated that the administration of NH4Cl after viral infection inhibited the proliferation of a variety of fish viruses, encompassing both DNA and RNA viruses. Further studies have indicated that NH4Cl obstructed autophagy-dependent virus proliferation of spring viremia of carp virus (SVCV) by inhibiting autophagic flux. The molecular mechanism revealed that SVCV contributed to the polyubiquitination of interferon regulatory factor 3 (IRF3) and promoted the degradation of IRF3 through cargo receptor sequestosome 1 (SQSTM1/p62)-mediated selective autophagy. However, NH4Cl was observed to inhibit SVCV-mediated selective autophagy of IRF3, thereby facilitating the production of interferon. Furthermore, the SVCV N protein was of critical importance in this process. Nevertheless, NH4Cl impeded this degradation process by inhibiting the autophagy pathway. The study found that NH4Cl was highly efficacious in controlling fish virus infection both in vivo and in vitro. It can therefore be concluded that the antiviral effect of ammonia fertilizers was, at least in part, due to the inhibition of viral autophagy.

The erythroblastic island (EBI) functions as a niche in which erythroblastic island macrophages (EBIMφs) are positioned within rings of erythroblasts, providing support and signals that orchestrate efficient erythropoiesis. We postulated burn injury impacts the EBI niche, given the nearly universal presence of anemia and inflammation in burn patients, and a divergent myeloid transcriptional signature that we observed in murine bone marrow following burn injury, in which granulocyte colony-stimulating factor (G-CSF) secretion broadly attenuated the expression of EBIMφ marker genes. Notably, we identified the heme-induced transcription factor Spi-C as a robust marker of EBIMφs in Spicigfp/igfp mice. Two bone marrow cell populations, macrophages and Gr1-low monocytes, possessed cell-intrinsic Spic-GFP. Spic+ macrophages were distinguished by higher levels of green fluorescent protein, autofluorescence, F4/80, and CD163 while CD115 staining was negligible compared with Gr1-low monocytes. Application of Spicigfp/igfp mice in studies revealed a G-CSF-dependent reduction of Spic+ macrophages in postburn marrow, which coincided with a loss of erythroid cells and that G-CSF administration was sufficient to reduce Spic+ macrophages in the marrow. These results provide the first evidence that burn injuries impact the EBI niche through G-CSF-dependent reduction of Spic+ EBIMφs and support the use of Spicigfp/igfp mice in investigation of EBIMφs.

The 2022 Mpox virus (MPXV) outbreak revitalized questions about immunity against MPXV and vaccinia-based vaccines (VAC-V), but studies are limited. We analyzed immunity against MPXV in individuals infected with MPXV or vaccinated with the licensed modified vaccinia Ankara (MVA) Bavarian Nordic or an experimental MVA-HIVB vaccine. The frequency of neutralizing antibody responders was higher among MPXV-infected individuals than MVA vaccinees. Both MVA vaccines induced similar and strong humoral responses. Similarly, we show a higher frequency and magnitude (5-fold) of T cell responses, mainly mediated by CD8+ T cells, against a peptide pool containing selected sequences from MPXV, variola, and VAC-V in MPXV-infected individuals than MVA vaccinees. We describe a hierarchy of cross-reactive T cell responses against 5 peptide pools that are highly homologous between VAC-V and MPXV 2022, with the highest frequency of responders against MVA-121L and MVA-018L proteins. Both vaccines stimulated a notable frequency of polyfunctional CD4+ and CD8+ T cell responses, with a subset of CD4+ T cells showing a mixed cytokine profile. Finally, we found that smallpox vaccination in childhood positively affected humoral but not T cell vaccine responses, whereas these responses were not affected in people living with HIV. These findings contribute to deciphering and monitoring the profile of immunity to MPXV and MVA. In the context of a potential threat of the reemergence of smallpox following bioterrorism, the diversification and availability of potent vaccines is crucial. The comparable immunogenicity of both MVA vaccines emphasizes the potential utility of MVA-HIVB as a valuable new tool for controlling MPXV outbreaks.

Food allergy has had a rapid rise in prevalence, and thus it is important to identify approaches to limit the development of food allergy early in life. Because maternal dietary supplementation with α-tocopherol (α-T), an isoform of vitamin E, during pregnancy and nursing increases neonate plasma levels of α-T and can limit neonate development of other allergies, we hypothesized that α-T can limit development of food allergy. To assess this, male mice with mutations in their skin barrier genes (FT-/- mice) were mated with wild-type females that received a diet supplemented with α-tocopherol or a control diet. Starting at postnatal day 3, these FT+/- pups were sensitized 4 to 5 times over 2.5 weeks by skin co-exposure to the food allergen peanut extract (PNE) and the environmental allergen Alternaria alternata (Alt). Control pups were exposed to saline, PNE only or Alt only. Supplementation with α-T blocked Alt+PNE sensitization (anti-PNE-specific IgE), without blocking Alt+PNE-stimulated skin IL33, Areg, OSM, CCL11, TSLP or plasma MCPT1. However, supplementation with α-T blocked mast cell activation, the increase in plasma histamine in Alt+PNE sensitized pups, histamine receptor stimulation of endothelial PKCα signaling, and ultimately oral PNE-induced anaphylaxis in Alt+PNE sensitized mice. Thus, maternal supplementation with α-tocopherol reduced development of food allergy and anaphylaxis in neonates. These results have implications for supplementation of mothers with α-tocopherol to limit development of food allergy in neonates with skin barrier mutations.

Interleukin (IL)-18 is an immunoregulatory cytokine that acts as a potent inducer of T helper 1 and cytotoxic responses. IL-18 activity is regulated by its decoy receptor IL-18 binding protein (IL-18BP) which forms a high affinity complex with IL-18 to block binding of the cognate receptors. A disbalance between IL-18 and IL-18BP associated with excessive IL-18 signaling can lead to systemic inflammation. Indeed, the severity of CpG-induced macrophage activation syndrome (MAS) is exacerbated in IL-18BP KO mice. On the contrary, targeting IL-18BP can have promising effects to enhance immune responses against pathogens and cancer. We generated monoclonal rabbit anti-mouse IL-18BP antibodies labeled from 441 to 450. All antibodies, except from antibody 443, captured mIL-18BP when used in a sandwich ELISA. Using an IL-18 bioassay, we showed that antibody 441 did not interfere with the regulatory effect of mIL-18BP, whereas all other antibodies displayed different levels of antagonism. Further experiments were performed using antibody 445 endowed with potent neutralizing activity and antibody 441. Despite binding to IL-18BP with the same affinity, antibody 445, but not antibody 441, was able to release IL-18 from preformed IL-18-IL-18BP complexes. Administration of antibody 445 significantly aggravated the severity of CpG-induced MAS as compared to antibody 441. Additional experiments using naïve WT, IL-18BP KO, and IL-18 KO mice confirmed the specificity of the neutralizing effect of antibody 445 towards IL-18BP. Our studies led to the development of a monoclonal anti-IL-18BP antibody with neutralizing activity that results in the promotion of IL-18 activities.