bims-traimu Biomed News
on Trained immunity
Issue of 2023‒09‒24
six papers selected by
Yantong Wan, Southern Medical University

  1. J Innate Immun. 2023 Sep 21.
      Epigenetic reprogramming of innate immune cells by β-glucan in a process called trained immunity, leads to an enhanced host response to a secondary infection. β-glucans are structural components of plants, algae, fungi and bacteria and thus recognized as non-self by human macrophages. We selected the β-glucans curdlan from Alcaligenes faecalis, WGP dispersible from Saccharomyces cerevisiae, and β-glucan-rich culture supernatant of Alternaria and investigated whether they could produce trained immunity effects leading to an increased control of virulent Mycobacterium tuberculosis. We observed a significant M. tuberculosis growth-reduction in macrophages trained with curdlan and Alternaria, which also correlated with increased IL-6 and IL-1β release. WGP dispersible-trained macrophages were stratified into 'non responders' and 'responders', according to their ability to control M. tuberculosis, with 'responders' producing higher IL-6 levels. The addition of neutrophils to infected macrophage cultures further enhanced macrophage control of virulent M. tuberculosis, but not in a stimuli-dependent manner. Pathway enrichment analysis of DNA methylome data also highlighted hypomethylation of genes in pathways associated with signaling and cellular reorganization and motility, and 'responders' to WGP-training were enriched in the interferon-gamma signaling pathway. This study adds evidence that certain β-glucans show promise as immune training agents.
  2. Immunohorizons. 2023 Sep 01. 7(9): 626-634
      The bacillus Calmette-Guérin (BCG) vaccine, administered to prevent tuberculosis, is a well-studied inducer of trained immunity in human and mouse monocytes. We have previously demonstrated that aerosol BCG administration induces innate training in calves. The current study aimed to determine whether s.c. BCG administration could induce innate training, identify the cell type involved, and determine whether innate training promoted resistance to bovine respiratory syncytial virus (BRSV) infection, a major cause of bovine respiratory disease in preweaned calves. A total of 24 calves were enrolled at 1-3 d of age and blocked by age into two treatment groups (BCG, n = 12; control, n = 12). BCG was given s.c. to preweaned calves. The control calves received PBS. We observed a trained phenotype, demonstrated by enhanced cytokine production in response to in vitro stimulation with LPS (TLR-4 agonist) in PBMCs and CD14+ monocytes from the BCG group 2 wk (IL-1β, p = 0.002) and 4 wk (IL-1β, p = 0.005; IL-6, p = 0.013) after BCG administration, respectively. Calves were experimentally infected via aerosol inoculation with BRSV strain 375 at 5 wk after BCG administration and necropsied on day 8 postinfection. There were no differences in disease manifestation between the treatment groups. Restimulation of bronchoalveolar lavage fluid cells isolated on day 8 after BRSV infection revealed enhanced IL-1β (p = 0.014) and IL-6 (p = 0.010) production by the BCG group compared with controls. In conclusion, results from our study show that s.c. administration of the BCG vaccine can induce trained immunity in bovine monocytes and influence cytokine production in the lung environment after BRSV infection.
  3. Front Immunol. 2023 ;14 1268916
      To determine the roles of endoplasmic reticulum (ER) stress and trained immunity, we performed transcriptome analyses on the thoracic aorta (TA) and abdominal aorta (AA) from the angiotensin II (Ang II)-HFD-ApoE-KO aneurysm model and made significant findings: 1) Ang II bypassed HFD-induced metabolic reprogramming and induced stronger inflammation in AA than in TA; 2) Ang II and HFD upregulated 890 genes in AA versus TA and induced cytokine signaling; 3) Ang II AA and TA upregulated 73 and 68 cytokines, scRNA-Seq identified markers of macrophages and immune cells, cell death regulators, respectively; transdifferentiation markers of neuron, glial, and squamous epithelial cells were upregulated by Ang II-AA and TA; and pyroptosis signaling with IL-1β and caspase-4 were more upregulated in Ang II-AA than in TA; 4) Six upregulated transcriptomes in patients with AAA, Ang II AA, Ang II TA, additional aneurysm models, PPE-AAA and BAPN-Ang II-AAA, were partially overlapped with 10 lists of new ER stress gene sets including 3 interaction protein lists of ER stress regulators ATF6, PERK, and IRE1, HPA ER localization genes, KEGG signal genes, XBP1 transcription targets, ATF4 (PERK) targets, ATF6 targets, thapsigargin ER stress genes, tunicamycin-ER stress genes, respectively; 5) Ang II-AA and TA upregulated ROS regulators, MitoCarta genes, trained immunity genes, and glycolysis genes; and 6) Gene KO transcriptomes indicated that ATF6 and PERK played more significant roles than IRE1 in promoting AAA and trained immunity whereas antioxidant NRF2 inhibited them. Our unprecedented ER-focused transcriptomic analyses have provided novel insights on the roles of ER as an immune organelle in sensing various DAMPs and initiating ER stress that triggers Ang II-accelerated trained immunity and differs susceptibilities of thoracic and abdominal aortas to diseases.
    Keywords:  Ang II; ER stress; metabolic reprogramming; trained immunity; vascular inflammation
  4. Nanomedicine (Lond). 2023 Sep 19.
      Tweetable abstract Commentary just out in @fsgnnm: unleashing the full potential of #cancer #nanomedicines by reprogramming the immunosuppressive #TME using #LNP #mRNA #vaccines and via promoting #trainedimmunity.
    Keywords:  cancer nanomedicine; cancer vaccines; immuno-oncology; immunotherapy; lipid nanoparticles; mRNA; trained immunity
  5. EClinicalMedicine. 2023 Oct;64 102203
    BRACE Trial Consortium Group
      Background: Recurrences of herpes simplex virus (HSV) in the orofacial region (herpes labialis or cold sores) impact quality-of-life. We aimed to study whether the bacille Calmette-Guérin (BCG) vaccine can attenuate cold sore recurrences through off-target immunomodulatory effects.Methods: In this nested randomised controlled trial within the multicentre, phase 3 BRACE trial, 6828 healthcare workers were randomised in 36 sites in Australia, the Netherlands, Spain, the United Kingdom and Brazil, to receive BCG-Denmark or no BCG (1:1 ratio using a web-based procedure) and followed for 12 months with 3-monthly questionnaires. Exclusion criteria included contraindication to BCG vaccine or previous vaccination with BCG within the past year, any other live-attenuated vaccine within the last month, or any COVID-specific vaccine. The intervention group received one intradermal dose of 0.1 mL of BCG-Denmark corresponding to 2-8 x 105 colony forming units of Mycobacterium bovis, Danish strain 1331. The primary outcome was the difference in restricted mean survival time (i.e., time to first cold-sore recurrence), in participants with frequent recurrent herpes labialis (≥4 recurrences/year), analysed by intention-to-treat. Secondary outcomes addressed additional questions, including analyses in other sub-populations. Adverse events were monitored closely during the first 3 months and were reported in all participants who received one dose of study drug according to intervention received. The BRACE trial is registered with, NCT04327206.
    Findings: Between March 30, 2020 and February 18, 2021, 84 individuals with frequent recurrent cold sores were randomly assigned to BCG (n = 38) or control (n = 46). The average time to first cold-sore recurrence was 1.55 months longer in the BCG group (95% CI 0.27-2.82, p = 0.02) than the control group (hazard ratio 0.54, 95% CI 0.32-0.91; intention-to-treat). The beneficial effect of BCG was greater in the as-treated population (difference 1.91 months, 95% CI 0.69-3.12, p = 0.003; hazard ratio 0.45, 95% CI 0.26-0.76). In prespecified subgroup analyses, only sex modified the treatment effect (interaction p = 0.007), with benefit restricted to males. Over 12 months, a greater proportion of participants in the BCG group compared with the control group reported a decrease in duration (61% vs 21%), severity (74% vs 21%), frequency (55% vs 21%), and impact on quality of life (42% vs 15%) of cold sore recurrences. In participants who had ever had a cold sore, there was also a decrease in self-reported burden of recurrences in the BCG group. In participants who had never had a cold sore, there was an increased risk of a first episode in the BCG group (risk difference 1.4%; 95% CI 0.3-2.6%, p = 0.02). There were no safety concerns.
    Interpretation: BCG-Denmark vaccination had a beneficial effect on herpes labialis, particularly in males with frequent recurrences, but may increase the risk of a first cold sore.
    Funding: Bill & Melinda Gates Foundation, the Minderoo Foundation, Sarah and Lachlan Murdoch, the Royal Children's Hospital Foundation, Health Services Union NSW, the Peter Sowerby Foundation, SA Health, the Insurance Advisernet Foundation, the NAB Foundation, the Calvert-Jones Foundation, the Modara Pines Charitable Foundation, the UHG Foundation Pty Ltd, Epworth Healthcare, and individual donors.
    Keywords:  Bacille Calmette-Guérin; Cold sore; Herpes labialis; Herpes simplex virus; Heterologous immunity; Mycobacterium bovis; Non-specific effects; Off-target effects; Prevention; Secondary prophylaxis
  6. Int Immunopharmacol. 2023 Sep 14. pii: S1567-5769(23)01242-0. [Epub ahead of print]124(Pt A): 110917
      T cells play an important role in regulating immune system balance. Sepsis-associated immunosuppression causes apoptosis of T cells and a decrease in their number. Previously, artesunate was found to have an immunomodulatory effect on immunosuppression in model mice with cecal ligation and puncture (CLP)-induced sepsis. In the present study, mouse sepsis models of CLP and CLP with secondary infection were established and treated with artesunate in order to examine the effect of artesunate on adaptive immune response in sepsis-related immunosuppression. The results showed that artesunate treatment could increase the survival rate of CLP mice with secondary Pseudomonas aeruginosa infection, increase the bacterial clearance rate, and also increase the level of the pro-inflammatory cytokine TNF-α. In addition, artesunate resulted in an increase in the number of T cells, CD4+ T cells and CD8+ T cells, and inhibited CD4+ and CD8+ T-cell apoptosis. Artesunate was also found to inhibit the expression of the inhibitory receptors of PD-1, CTLA-4, and BTLA, but it did not affect the expression of Tim-3. Additionally, artesunate significantly increased the phosphorylated ERK level of CD4+ T cells and CD8+ T cells and inhibited mitochondrial pathway-mediated apoptosis in CLP mice with Pseudomonas aeruginosa infection. These findings reveal that artesunate has an immunomodulatory effect on the adaptive immune response in sepsis. These effects include an increase in the numbers of T cells, CD4+ T cells, and CD8+ T cells through inhibition of the expression of inhibitory receptors and promotion of the MAPK/ERK pathway.
    Keywords:  Apoptosis; Artesunate; Immunosuppression; Secondary infection; Sepsis; T cells