Immunology & Cell Biology最新文献

In this article, we discuss the recent observation by Augusto et al. made using a novel mobile phone application-based COVID-19 Citizen Science Study that an HLA genetic variant, HLA-B*15:01, is associated with asymptomatic SARS-CoV-2 infection. To explain this association, Augusto et al. describe a cross-reactive memory CD8⁺ T-cell response in HLA-B*15:01⁺ SARS-CoV-2 unexposed individuals that retains high avidity for two structurally conserved epitopes found in SARS-CoV-2 and seasonal coronavirus strains. These observations provide an insight into potential molecular determinants that facilitate rapid, early clearance of virus.

Between 1953 and 1986, Bede Morris published 28 papers in the Journal, each of which elucidated aspects of the lymphatic system. Initially with rats at the Kanematsu Institute at Sydney Hospital under FC Courtice, and then at Australian National University with sheep and a succession of PhD students, Morris developed an impressive series of experimental approaches and understandings of the role of the lymphatic system in the physiology and immunology of the mammalian body. In this piece for the 100th anniversary of the Journal, we celebrate his contributions to immunological research.

Between 1969 and 1983 the lab of Kevin Lafferty in Canberra developed the concept of the T-cell “costimulator,” an essential second signal for activation. A great deal of the work appeared in this journal before it was known as Immunology & Cell Biology (ICB). As part of the 100-year anniversary of the journal, I offer a personal reflection on Kevin's legacy and impact.

Current serological tests cannot differentiate between total immunoglobulin A (IgA) and dimeric IgA (dIgA) associated with mucosal immunity. Here, we describe two new assays, dIgA-ELISA and dIgA-multiplex bead assay (MBA), that utilize the preferential binding of dIgA to a chimeric form of secretory component, allowing the differentiation between dIgA and monomeric IgA. dIgA responses elicited through severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection were measured in (i) a longitudinal panel, consisting of 74 samples (n = 20 individuals) from hospitalized cases of coronavirus disease 2019 (COVID-19); (ii) a longitudinal panel, consisting of 96 samples (n = 10 individuals) from individuals with mild COVID-19; (iii) a cross-sectional panel with PCR-confirmed SARS-CoV-2 infection with mild COVID-19 (n = 199) and (iv) pre–COVID-19 samples (n = 200). The dIgA-ELISA and dIgA-MBA demonstrated a specificity for dIgA of 99% and 98.5%, respectively. Analysis of dIgA responses in the longitudinal panels revealed that 70% (ELISA) and 50% (MBA) of patients elicited a dIgA response by day 20 after PCR diagnosis with a SARS-CoV-2 infection. Individuals with mild COVID-19 displayed increased levels of dIgA within the first 3 weeks after diagnosis but responses appeared to be short lived, compared with sustained IgA levels. However, in samples from hospitalized patients with COVID-19 we observed high and sustained levels of dIgA, up to 245 days after PCR diagnosis. Our results suggest that severe COVID-19 infections are associated with sustained levels of plasma dIgA compared with mild cases.

Artificial antigen-presenting cells (aAPCs) offer a cost effective and convenient tool for the expansion of chimeric antigen receptor (CAR)-bearing T cells and NK cells. aAPCs are particularly useful because of their ability to efficiently expand low-frequency antigen-reactive lymphocytes in bulk cultures. Commonly derived from the leukemic cell line K562, these aAPCs lack most major histocompatibility complex expression and are therefore useful for NK cell expansion without triggering allogeneic T-cell proliferation. To combat difficulties in accessing existing aAPC lines, while circumventing the iterative lentiviral gene transfers with antibody-mediated sorting required for the isolation of stable aAPC clones, we developed a single-step technique using Sleeping Beauty (SB)–based vectors with antibiotic selection options. Our SB vectors contain options of two to three genes encoding costimulatory molecules, membrane-bound cytokines as well as the presence of antibiotic-resistance genes that allow for stable transposition-based transfection of feeder cells. Transfection of K562 with SB vectors described in this study allows for the surface expression of CD86, 4-1BBL, membrane-bound (mb) interleukin (IL)-15 and mbIL-21 after simultaneous transposition and antibiotic selection using only two antibiotics. aAPCs successfully expanded NK cells to high purity (80–95%). Expanded NK cells could be further engineered by lentiviral CAR transduction. The multivector kit set is publicly available and will allow convenient and reproducible in-house production of effective aAPCs for the in vitro expansion of primary cells.

Alcohol can induce a leaky gut, with translocation of microbial molecules from the gut into the blood circulation. Although the contribution of inflammation to organ-mediated damage in lupus has been previously demonstrated, the mechanistic roles of alcohol consumption in lupus activation are not known. Herein, we tested the effects of 10-week lasting alcohol administration on organ damages and immune responses in 8-week-old lupus-prone Fc gamma receptor IIb–deficient (FcγRIIb^−/−) mice. Our study endpoints were evaluation of systemic inflammation and assessment of fecal dysbiosis along with endotoxemia. In comparison with alcohol-administered wild-type mice, FcγRIIb^−/− mice demonstrated more prominent liver damage (enzyme, histological score, apoptosis, malondialdehyde oxidant) and serum interleukin(IL)-6 levels, despite a similarity in leaky gut (fluorescein isothiocyanate–dextran assay, endotoxemia and gut occludin-1 immunofluorescence), fecal dysbiosis (microbiome analysis) and endotoxemia. All alcohol-administered FcγRIIb^−/− mice developed lupus-like characteristics (serum anti-dsDNA, proteinuria, serum creatinine and kidney injury score) with spleen apoptosis, whereas control FcγRIIb^−/− mice showed only a subtle anti-dsDNA. Both alcohol and lipopolysaccharide (LPS) similarly impaired enterocyte integrity (transepithelial electrical resistance), and only LPS, but not alcohol, upregulated the IL-8 gene in Caco-2 cells. In macrophages, alcohol mildly activated supernatant cytokines (tumor necrosis factor-α and IL-6), but not M1 polarization–associated genes (IL-1β and iNOS), whereas LPS prominently induced both parameters (more prominent in FcγRIIb^−/− macrophages than wild type). There was no synergy in LPS plus alcohol compared with LPS alone in both enterocytes and macrophages. In conclusion, alcohol might exacerbate lupus-like activity partly through a profound inflammation from the leaky gut in FcγRIIb^−/− mice.

It is easy to feel as if you are alone in academia, especially if you face challenges that not everyone does, or can, understand. Community is essential in facing these challenges, and we each have a role to play in creating a more equitable research community. Here, I discuss the importance of community, finding your village and being part of the academic support system.

Spatial biology is a rapidly developing field which enables the visualization of protein and transcriptomic data while preserving tissue context and architecture. Initially used in discovery, there is growing promise for translational and diagnostic assay developments. Immediate applications are in precision medicine, such as being able to match patients to optimal therapies through better understanding the tumor microenvironment. However, it also has ramifications for many other disciplines (e.g. immunology, cancer, infectious disease and digital pathology). With increasingly massive data sets being generated, data storage, curation, analysis and sharing require more computational approaches and artificial intelligence–powered tools to fully utilize spatial tools. Here, we discuss spatial biology as an important convergent science approach to tackling complex global challenges in areas such as health.

The PE_PGRS proteins have coevolved with the antigenic ESX-V secretory system and are abundant in pathogenic Mycobacterium. Only a few PE_PGRS proteins have been characterized, and research suggests their role in organelle targeting, cell death pathways, calcium (Ca²⁺) homeostasis and disease pathogenesis. The PE_PGRS45 (Rv2615c) protein was predicted to contain mitochondria targeting sequences by in silico evaluation. Therefore, we investigated the targeting of the Rv2615c protein to host mitochondria and its effect on mitochondrial functions. In vitro experiments showed the Rv2615c protein colocalized with the mitochondria and led to morphological mitochondrial perturbations. Recombinant Rv2615c was observed to cause increased levels of intracellular reactive oxygen species and the adenosine diphosphate-to-adenosine triphosphate ratio. The Rv2615c protein also induced mitochondrial membrane depolarization and the generation of mitochondrial superoxide. We observed the release of cytochrome C into the cytoplasm and increased expression of proapoptotic genes Bax and Bim with no significant change in anti-apoptotic Bcl2 in Rv2615c-stimulated THP1 macrophages. Ca²⁺ is a key signaling molecule in tuberculosis pathogenesis, modulating host cell responses. As reported for other PE_PGRS proteins, Rv2615c also has Ca²⁺-binding motifs and thus can modulate calcium homeostasis in the host. We also observed a high level of Ca²⁺ influx in THP1 macrophages stimulated with Rv2615c. Based on these findings, we suggest that Rv2615c may be an effector protein that could contribute to disease pathogenesis by targeting host mitochondria.

Singapore stands as a dynamic hub for cutting-edge immunological research and innovation. The country's vibrant research ecosystem is supported by collaborative networks across the many national medical and scientific research institutes, fostering meaningful alliances between academia and industry. In this article, we speak to Assistant Professor Jinmiao Chen from the Agency for Science, Technology, and Research (A*STAR) and Professor Nicholas Gascoigne from the National University of Singapore (NUS), Duke-NUS Medical School and Nanyang Technological University (NTU) about immunology in Singapore. Credit: Kate Forbes.