The kinase complex mTORC2 promotes the longevity of virus-specific memory CD4+ T cells by preventing ferroptosis.

Antigen-specific memory CD4+ T cells can persist and confer rapid and efficient protection from microbial reinfection. However, the mechanisms underlying the long-term maintenance of the memory CD4+ T cell pool remain largely unknown. Here, using a mouse model of acute infection with lymphocytic choriomeningitis virus (LCMV), we found that the serine/threonine kinase complex mammalian target of rapamycin complex 2 (mTORC2) is critical for the long-term persistence of virus-specific memory CD4+ T cells. The perturbation of mTORC2 signaling at memory phase led to an enormous loss of virus-specific memory CD4+ T cells by a unique form of regulated cell death (RCD), ferroptosis. Mechanistically, mTORC2 inactivation resulted in the impaired phosphorylation of downstream AKT and GSK3ß kinases, which induced aberrant mitochondrial reactive oxygen species (ROS) accumulation and ensuing ferroptosis-causative lipid peroxidation in virus-specific memory CD4+ T cells; furthermore, the disruption of this signaling cascade also inhibited glutathione peroxidase 4 (GPX4), a major scavenger of lipid peroxidation. Thus, the mTORC2-AKT-GSK3ß axis functions as a key signaling hub to promote the longevity of virus-specific memory CD4+ T cells by preventing ferroptosis.

PB2 residue 473 contributes to the mammalian virulence of H7N9 avian influenza virus by modulating viral polymerase activity via ANP32A.

Since the first human infection reported in 2013, H7N9 avian influenza virus (AIV) has been regarded as a serious threat to human health. In this study, we sought to identify the virulence determinant of the H7N9 virus in mammalian hosts. By comparing the virulence of the SH/4664 H7N9 virus, a non-virulent H9N2 virus, and various H7N9-H9N2 hybrid viruses in infected mice, we first pinpointed PB2 as the primary viral factor accounting for the difference between H7N9 and H9N2 in mammalian virulence. We further analyzed the in vivo effects of individually mutating H7N9 PB2 residues different from the closely related H9N2 virus and consequently found residue 473, alongside the well-known residue 627, to be critical for the virulence of the H7N9 virus in mice and the activity of its reconstituted viral polymerase in mammalian cells. The importance of PB2-473 was further strengthened by studying reverse H7N9 substitutions in the H9N2 background. Finally, we surprisingly found that species-specific usage of ANP32A, a family member of host factors connecting with the PB2-627 polymorphism, mediates the contribution of PB2 473 residue to the mammalian adaption of AIV polymerase, as the attenuating effect of PB2 M473T on the viral polymerase activity and viral growth of the H7N9 virus could be efficiently complemented by co-expression of chicken ANP32A but not mouse ANP32A and ANP32B. Together, our studies uncovered the PB2 473 residue as a novel viral host range determinant of AIVs via species-specific co-opting of the ANP32 host factor to support viral polymerase activity.IMPORTANCEThe H7N9 avian influenza virus has been considered to have the potential to cause the next pandemic since the first case of human infection reported in 2013. In this study, we identified PB2 residue 473 as a new determinant of mouse virulence and mammalian adaptation of the viral polymerase of the H7N9 virus and its non-pathogenic H9N2 counterparts. We further demonstrated that the variation in PB2-473 is functionally linked to differential co-opting of the host ANP32A protein in supporting viral polymerase activity, which is analogous to the well-known PB2-627 polymorphism, albeit the two PB2 positions are spatially distant. By providing new mechanistic insight into the PB2-mediated host range determination of influenza A viruses, our study implicated the potential existence of multiple PB2-ANP32 interfaces that could be targets for developing new antivirals against the H7N9 virus as well as other mammalian-adapted influenza viruses.

CD160 Signaling Is Essential for CD8+ T Cell Memory Formation via Upregulation of 4-1BB.

A better understanding of the regulatory mechanisms governing the development of memory CD8+ T cells could provide instructive insights into vaccination strategies and T cell-based immunotherapies. In this article, we showed that CD160 surface protein is required for CD8+ T cell memory formation. In the response to acute lymphocytic choriomeningitis virus infection in a mouse model, CD160 ablation resulted in the failure of the development of all three memory CD8+ T cell subsets (central, effective, and tissue-resident memory), concomitant with a skewed differentiation into short-lived effector T cells. Such memory-related defect was manifested by a diminished protection from viral rechallenge. Mechanistically, CD160 deficiency led to downregulation of 4-1BB in activated CD8+ T cells, which contributes to the impaired cell survival and decreased respiratory capacity. The nexus between CD160 and 4-1BB was substantiated by the observation that ectopic introduction of 4-1BB was able to largely complement the loss of CD160 in memory CD8+ T cell development. Collectively, our studies discovered that CD160, once thought to be a coinhibitor of T cell signaling, is an essential promoter of memory CD8+ T cell development via activation of the costimulatory molecule 4-1BB.

Broad-spectrum vaccine via combined immunization routes triggers potent immunity to SARS-CoV-2 and its variants.

IMPORTANCE: The development of broad-spectrum SARS-CoV-2 vaccines will reduce the global economic and public health stress from the COVID-19 pandemic. The use of conserved T-cell epitopes in combination with spike antigen that induce humoral and cellular immune responses simultaneously may be a promising strategy to further enhance the broad spectrum of COVID-19 vaccine candidates. Moreover, this research suggests that the combined vaccination strategies have the ability to induce both effective systemic and mucosal immunity, which may represent promising strategies for maximizing the protective efficacy of respiratory virus vaccines.

Sub-inhibitory concentrations of tetrabromobisphenol A induce the biofilm formation of methicillin-resistant Staphylococcus aureus.

Biofilm formation by methicillin-resistant Staphylococcus aureus (MRSA) on indwelling medical devices complicates the treatment of infection. Tetrabromobisphenol A (TBBPA), a synthetic, lipophilic, halogenated aromatic compound widely used as an additive in plastics and electronic products, has raised environmental concerns due to its potential for bioaccumulation. This study investigated the impact of sub-inhibitory concentrations of TBBPA on MRSA biofilm formation. Crystal violet staining and confocal laser scanning microscopy analysis demonstrated that 1/8 MIC (0.5 µg/mL) of TBBPA significantly stimulated MRSA biofilm formation (P < 0.0001). MTT assays indicated that the metabolic activity within the biofilms increased by 15.60-40.85% compared to untreated controls. Dot blot immunoassay, autolysis assay, and extracellular DNA (eDNA) quantification further revealed TBBPA enhanced the production of polysaccharide intercellular adhesin (PIA) and eDNA, which are key biofilm components. Additionally, TBBPA was found to enhance the production of staphyloxanthin, facilitating MRSA survival under oxidative conditions and in human whole blood. RT-qPCR analysis showed that TBBPA significantly upregulated genes associated with biofilm formation (icaA, atlA, sarA), staphyloxanthin biosynthesis (crtM and sigB), and oxidative stress responses (sodA and katA). These findings suggest that TBBPA promotes MRSA biofilm development and enhances bacterial resistance to adverse conditions, thereby potentially exacerbating risks to human health.

Nonmuscle myosin heavy chain IIA facilitates SARS-CoV-2 infection in human pulmonary cells.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of coronavirus disease 2019 (COVID-19), binds to host receptor angiotensin-converting enzyme 2 (ACE2) through its spike (S) glycoprotein, which mediates membrane fusion and viral entry. However, the expression of ACE2 is extremely low in a variety of human tissues, especially in the airways. Thus, other coreceptors and/or cofactors on the surface of host cells may contribute to SARS-CoV-2 infection. Here, we identified nonmuscle myosin heavy chain IIA (MYH9) as an important host factor for SARS-CoV-2 infection of human pulmonary cells by using APEX2 proximity-labeling techniques. Genetic ablation of MYH9 significantly reduced SARS-CoV-2 pseudovirus infection in wild type (WT) A549 and Calu-3 cells, and overexpression of MYH9 enhanced the pseudovirus infection in WT A549 and H1299 cells. MYH9 was colocalized with the SARS-CoV-2 S and directly interacted with SARS-CoV-2 S through the S2 subunit and S1-NTD (N-terminal domain) by its C-terminal domain (designated as PRA). Further experiments suggested that endosomal or myosin inhibitors effectively block the viral entry of SARS-CoV-2 into PRA-A549 cells, while transmembrane protease serine 2 (TMPRSS2) and cathepsin B and L (CatB/L) inhibitors do not, indicating that MYH9 promotes SARS-CoV-2 endocytosis and bypasses TMPRSS2 and CatB/L pathway. Finally, we demonstrated that loss of MYH9 reduces authentic SARS-CoV-2 infection in Calu-3, ACE2-A549, and ACE2-H1299 cells. Together, our results suggest that MYH9 is a candidate host factor for SARS-CoV-2, which mediates the virus entering host cells by endocytosis in an ACE2-dependent manner, and may serve as a potential target for future clinical intervention strategies.

NamiRNA-enhancer network of miR-492 activates the NR2C1-TGF-ß/Smad3 pathway to promote epithelial-mesenchymal transition of pancreatic cancer.

Pancreatic cancer (PaCa) is one of the most fatal malignancies of the digestive system, and most patients are diagnosed at advanced stages due to the lack of specific and effective tumor-related biomarkers for the early detection of PaCa. miR-492 has been found to be upregulated in PaCa tumor tissue and may serve as a potential therapeutic target. However, the molecular mechanisms by which miR-492 promotes PaCa tumor growth and progression are unclear. In this study, we first found that miR-492 in enhancer loci activated neighboring genes (NR2C1/NDUFA12/TMCC3) and promoted PaCa cell proliferation, migration, and invasion in vitro. We also observed that miR-492-activating genes significantly enriched the TGF-ß/Smad3 signaling pathway in PaCa to promote epithelial-mesenchymal transition (EMT) during tumorigenesis and development. Using CRISPR-Cas9 and ChIP assays, we further observed that miR-492 acted as an enhancer trigger, and that antagomiR-492 repressed PaCa tumorigenesis in vivo, decreased the expression levels of serum TGF-ß, and suppressed the EMT process by downregulating the expression of NR2C1. Our results demonstrate that miR-492, as an enhancer trigger, facilitates PaCa progression via the NR2C1-TGF-ß/Smad3 pathway.

Induced regulatory T cells modified by knocking down T-bet in combination with ectopic expression of inhibitory cytokines effectively protect graft-versus-host disease.

Induced regulatory T (iTreg) cells play a vital role in immune tolerance and in controlling chronic inflammation. Generated in the periphery, iTreg cells are suitable for responding to alloantigens and preventing transplant rejection. Nevertheless, their clinical application has been impeded by the plasticity and instability attributed to the loss of forkhead box protein 3 expression, raising concerns that iTreg may be converted to effector T cells and even exert a pathogenic effect. Herein, second-generation short hairpin RNAs loaded with 3 pairs of small interfering RNAs were utilized to target the T-box transcription factor TBX21. In addition, 2 immunosuppressive cytokines, namely, transforming growth factor beta and interleukin 10, were constitutively expressed. This novel engineering strategy allowed the generation of stably induced regulatory T (SI Treg) cells, which maintained the expression of forkhead box protein 3 even in an unfavorable environment and exerted potent immunosuppressive functions in vitro. Furthermore, SI Treg cells demonstrated an effector transcriptional profile. Finally, SI Treg cells showed a significant protective effect against graft-versus-host disease-related deaths in a xenotransplantation model. Collectively, these results signify that SI Treg cells hold great promise for future clinical application and offer a rational therapeutic approach for transplant rejection.

A Single Vaccine Protects against SARS-CoV-2 and Influenza Virus in Mice.

The ongoing SARS-CoV-2 pandemic poses a severe global threat to public health, as do influenza viruses and other coronaviruses. Here, we present chimpanzee adenovirus 68 (AdC68)-based vaccines designed to universally target coronaviruses and influenza. Our design is centered on an immunogen generated by fusing the SARS-CoV-2 receptor-binding domain (RBD) to the conserved stalk of H7N9 hemagglutinin (HA). Remarkably, the constructed vaccine effectively induced both SARS-CoV-2-targeting antibodies and anti-influenza antibodies in mice, consequently affording protection from lethal SARS-CoV-2 and H7N9 challenges as well as effective H3N2 control. We propose our AdC68-vectored coronavirus-influenza vaccine as a universal approach toward curbing respiratory virus-causing pandemics. IMPORTANCE The COVID-19 pandemic exemplifies the severe public health threats of respiratory virus infection and influenza A viruses. The currently envisioned strategy for the prevention of respiratory virus-causing diseases requires the comprehensive administration of vaccines tailored for individual viruses. Here, we present an alternative strategy by designing chimpanzee adenovirus 68-based vaccines which target both the SARS-CoV-2 receptor-binding-domain and the conserved stalk of influenza hemagglutinin. When tested in mice, this strategy attained potent neutralizing antibodies against wild-type SARS-CoV-2 and its emerging variants, enabling an effective protection against lethal SARS-CoV-2 challenge. Notably, it also provided complete protection from lethal H7N9 challenge and efficient control of H3N2-induced morbidity. Our study opens a new avenue to universally curb respiratory virus infection by vaccination.

SARS-COV-2 spike protein promotes RPE cell senescence via the ROS/P53/P21 pathway.

SARS-Cov-2 infection, which has caused the COVID-19 global pandemic, triggers cellular senescence. In this study, we investigate the role of the SARS-COV-2 spike protein (S-protein) in regulating the senescence of RPE cells. The results showed that administration or overexpression of S-protein in ARPE-19 decreased cell proliferation with cell cycle arrest at the G1 phase. S-protein increased SA-ß-Gal positive ARPE-19 cells with high expression of P53 and P21, senescence-associated inflammatory factors (e.g., IL-1ß, IL-6, IL-8, ICAM, and VEGF), and ROS. Elimination of ROS by N-acetyl cysteine (NAC) or knocking down p21 by siRNA diminished S-protein-induced ARPE cell senescence. Both administrated and overexpressed S-protein colocalize with the ER and upregulate ER-stress-associated BIP, CHOP, ATF3, and ATF6 expression. S-protein induced P65 protein nuclear translocation. Inhibition of NF-κB by bay-11-7082 reduced S-protein-mediated expression of senescence-associated factors. Moreover, the intravitreal injection of S-protein upregulates senescence-associated inflammatory factors in the zebrafish retina. In conclusions, the S-protein of SARS-Cov-2 induces cellular senescence of ARPE-19 cells in vitro and the expression of senescence-associated cytokines in zebrafish retina in vivo likely by activating ER stress, ROS, and NF-κb. These results may uncover a potential association between SARS-cov-2 infection and development of AMD.

Helicobacter pylori CagA Interacts with SHP-1 to Suppress the Immune Response by Targeting TRAF6 for K63-Linked Ubiquitination.

Helicobacter pylori is the major etiological agent for most gastric cancer. CagA has been reported to be an important virulence factor of H. pylori, but its effect on the immune response is not yet clear. In this study, wild-type C57BL/6 mice and Ptpn6me-v/me-v mice were randomly assigned for infection with H. pylori We demonstrated that CagA suppressed H. pylori-stimulated expression of proinflammatory cytokines in vivo. Besides, we infected mouse peritoneal macrophages RAW264.7 and AGS with H. pylori Our results showed that CagA suppressed expression of proinflammatory cytokines through inhibiting the MAPKs and NF-κB pathways activation in vitro. Mechanistically, we found that CagA interacted with the host cellular tyrosine phosphatase SHP-1, which facilitated the recruitment of SHP-1 to TRAF6 and inhibited the K63-linked ubiquitination of TRAF6, which obstructed the transmission of signal downstream. Taken together, these findings reveal a previously unknown mechanism by which CagA negatively regulates the posttranslational modification of TRAF6 in innate antibacterial immune response and provide molecular basis for new therapeutics to treat microbial infection.

Adipose-derived stem cells show hepatic differentiation potential and therapeutic effect in rats with acute liver failure.

Hepatocyte transplantation contributes to the repair of liver damage, but hepatocyte resources are limited, making it difficult for this to become a routine treatment. Previous studies have confirmed that mesenchymal stem cells (MSCs) can be induced to differentiate into hepatocyte-like cells (HLCs) by adding different cytokine combinations in vitro, and they then play some roles of hepatocytes. Our previous studies found that the differentiation ability of stem cells is closely related to the origin of the tissue. To identify the mesenchymal stem cells that are most suitable for hepatic differentiation and the treatment of liver failure, we use a three-phase induction process in which human adipose-derived stem cells (hADSCs) and umbilical cord mesenchymal stem cells (hUCMSCs) are induced to differentiate towards HLCs in vitro, and rats with acute liver failure (ALF) induced by D-gal are cured by MSCs and MSC-derived HLCs (MSCs-HLC), respectively. We find that hADSCs are stronger than hUCMSCs in hepatic differentiation ability, and they have a better curative effect when using hADSCs-HLC or jointly using hADSCs and hADSCs-HLC, which has positive significance for hepatocyte regeneration, recovery of liver function and reduction of systemic inflammatory reaction, finally improving the survival rate of rats with acute liver failure.

Scopoletin Reactivates Latent HIV-1 by Inducing NF-κB Expression without Global T Cell Activation.

Reversing HIV-1 latency promotes the killing of infected cells and is essential for cure strategies. However, current latency-reversing agents (LRAs) are not entirely effective and safe in activating latent viruses in patients. In this study, we investigated whether Scopoletin (6-Methoxy-7-hydroxycoumarin), an important coumarin phytoalexin found in plants with multiple pharmacological activities, can reactivate HIV-1 latency and elucidated its underlying mechanism. Using the Jurkat T cell model of HIV-1 latency, we found that Scopoletin can reactivate latent HIV-1 replication with a similar potency to Prostratin and did so in a dose- and time-dependent manner. Moreover, we provide evidence indicating that Scopoletin-induced HIV-1 reactivation involves the nuclear factor kappa B (NF-κB) signaling pathway. Importantly, Scopoletin did not have a stimulatory effect on T lymphocyte receptors or HIV-1 receptors. In conclusion, our study suggests that Scopoletin has the potential to reactivate latent HIV-1 without causing global T-cell activation, making it a promising treatment option for anti-HIV-1 latency strategies.

Revealing the characteristics of ZIKV infection through tissue-specific transcriptome sequencing analysis.

BACKGROUND: Recently, Zika virus (ZIKV) re-emerged in India and was potentially associated with microcephaly. However, the molecular mechanisms underlying ZIKV pathogenesis remain to be explored. RESULTS: Herein, we performed a comprehensive RNA-sequencing analysis on ZIKV-infected JEG-3, U-251 MG, and HK-2 cells versus corresponding uninfected controls. Combined with a series of functional analyses, including gene annotation, pathway enrichment, and protein-protein interaction (PPI) network analysis, we defined the molecular characteristics induced by ZIKV infection in different tissues and invasion time points. Data showed that ZIKV infection and replication in each susceptible organ commonly stimulated interferon production and down-regulated metabolic-related processes. Also, tissue-specific immune responses or biological processes (BPs) were induced after ZIKV infection, including GnRH signaling pathway in JEG-3 cells, MAPK signaling pathway in U-251 MG cells, and PPAR signaling pathway in HK-2 cells. Of note, ZIKV infection induced delayed antiviral interferon responses in the placenta-derived cell lines, which potentially explains the molecular mechanism by which ZIKV replicates rapidly in the placenta and subsequential vertical transmission occurs. CONCLUSIONS: Together, these data may provide a systemic insight into the pathogenesis of ZIKV infection in distinct human tissue-derived cell lines, which is likely to help develop prophylactic and therapeutic strategies against ZIKV infection.

Feasibility of iNKT cell and PD-1+CD8+ T cell-based immunotherapy in patients with lung adenocarcinoma: Preliminary results of a phase I/II clinical trial.

We performed a single-arm exploratory clinical trial that is ongoing and registered at ClinicalTrials.gov (NCT03093688). Patients were infused with autologous iNKT cells, PD-1 + CD8+ T cells, and dendritic cells every 3-5 weeks, which was considered 1 cycle. The primary endpoints were safety and objective tumor response. The preliminary results from the first three patients are reported here. The first patient received 16 cycles. Computed tomography (CT) examination revealed a stable disease (SD) response after 4 cycles and progressive disease (PD) response after 11 cycles. For the second patient that received 10 cycles, CT examination revealed an SD response after 4 cycles and a PD response after 9 cycles. For the third patient who was treated with 6 cycles, CT examination revealed an SD response after 4 cycles. The patients suffered from only grade 1-2 adverse events. iNKT cell and PD-1 + CD8+ T cell-based immunotherapy showed a manageable tolerability profile.

PEBP1 suppresses HIV transcription and induces latency by inactivating MAPK/NF-κB signaling.

The latent HIV-1 reservoir is a major barrier to viral eradication. However, our understanding of how HIV-1 establishes latency is incomplete. Here, by performing a genome-wide CRISPR-Cas9 knockout library screen, we identify phosphatidylethanolamine-binding protein 1 (PEBP1), also known as Raf kinase inhibitor protein (RKIP), as a novel gene inducing HIV latency. Depletion of PEBP1 leads to the reactivation of HIV-1 in multiple models of latency. Mechanistically, PEBP1 de-phosphorylates Raf1/ERK/IκB and IKK/IκB signaling pathways to sequestrate NF-κB in the cytoplasm, which transcriptionally inactivates HIV-1 to induce latency. Importantly, the induction of PEBP1 expression by the green tea compound epigallocatechin-3-gallate (EGCG) prevents latency reversal by inhibiting nuclear translocation of NF-κB, thereby suppressing HIV-1 transcription in primary CD4+ T cells isolated from patients receiving antiretroviral therapy (ART). These results suggest a critical role for PEBP1 in the regulation of upstream NF-κB signaling pathways governing HIV transcription. Targeting of this pathway could be an option to control HIV reservoirs in patients in the future.

Follicular CXCR5- expressing CD8(+) T cells curtail chronic viral infection.

During chronic viral infection, virus-specific CD8(+) T cells become exhausted, exhibit poor effector function and lose memory potential. However, exhausted CD8(+) T cells can still contain viral replication in chronic infections, although the mechanism of this containment is largely unknown. Here we show that a subset of exhausted CD8(+) T cells expressing the chemokine receptor CXCR5 has a critical role in the control of viral replication in mice that were chronically infected with lymphocytic choriomeningitis virus (LCMV). These CXCR5(+) CD8(+) T cells were able to migrate into B-cell follicles, expressed lower levels of inhibitory receptors and exhibited more potent cytotoxicity than the CXCR5(-) [corrected] subset. Furthermore, we identified the Id2-E2A signalling axis as an important regulator of the generation of this subset. In patients with HIV, we also identified a virus-specific CXCR5(+) CD8(+) T-cell subset, and its number was inversely correlated with viral load. The CXCR5(+) subset showed greater therapeutic potential than the CXCR5(-) [corrected] subset when adoptively transferred to chronically infected mice, and exhibited synergistic reduction of viral load when combined with anti-PD-L1 treatment. This study defines a unique subset of exhausted CD8(+) T cells that has a pivotal role in the control of viral replication during chronic viral infection.

Correlation Between Early Plasma Interleukin 37 Responses With Low Inflammatory Cytokine Levels and Benign Clinical Outcomes in Severe Acute Respiratory Syndrome Coronavirus 2 Infection.

BACKGROUND: The immune protective mechanisms during severe acute respiratory syndrome coronavirus (SARS-CoV-2) infection remain to be deciphered for the development of an effective intervention approach. METHODS: We examined early responses of interleukin 37 (IL-37), a powerful anti-inflammatory cytokine, in 254 SARS-CoV-2-infected patients before any clinical intervention and determined its correlation with clinical prognosis. RESULTS: Our results demonstrated that SARS-CoV-2 infection causes elevation of plasma IL-37. Higher early IL-37 responses were correlated with earlier viral RNA negative conversion, chest computed tomographic improvement, and cough relief, consequently resulted in earlier hospital discharge. Further assays showed that higher IL-37 was associated with lower interleukin 6 and interleukin 8 (IL-8) and higher interferon α responses and facilitated biochemical homeostasis. Low IL-37 responses predicted severe clinical prognosis in combination with IL-8 and C-reactive protein. In addition, we observed that IL-37 administration was able to attenuate lung inflammation and alleviate respiratory tissue damage in human angiotensin-converting enzyme 2-transgenic mice infected with SARS-CoV-2. CONCLUSIONS: Overall, we found that IL-37 plays a protective role by antagonizing inflammatory responses while retaining type I interferon, thereby maintaining the functionalities of vital organs. IL-37, IL-8, and C-reactive protein might be formulated as a precise prediction model for screening severe clinical cases and have good value in clinical practice.

CD8α- conventional dendritic cells control Vß T-cell immunity in response to Staphylococcus aureus infection in mice.

Dendritic cells (DCs) are potent immune cells that control innate and adaptive immune responses. Previous studies have shown that the DCs are required for protection against Staphylococcus aureus infection. However, the role of conventional DC (cDC) subsets during S. aureus infection in vivo has not been well investigated. In this study, we examined the function of spleen DC subsets in the activation of immunity against S. aureus infection. C57BL/6 mice were infected intravenously with S. aureus and DC and T-cell activation were analyzed in vivo. We found that the spleen CD8α- cDCs phagocytosed S. aureus more efficiently than type-1 conventional DCs (cDC1s) did. Moreover, the CD8α- cDCs contributed to the production of pro-inflammatory cytokines in response to S. aureus infection, whereas the cDC1s did not. In addition, infection with S. aureus promoted an increase in the number of Vß T cells. The CD4+ and CD8+ Vß T cells up-regulated the production of interferon-γ (IFN-γ) and interleukin-17 (IL-17) in response to S. aureus infection. Importantly, the induction of IFN-γ and IL-17 production in CD4+ and CD8+ Vß T cells was mediated by S. aureus-stimulated CD8α- cDCs, whereas cDC1s failed to promote IFN-γ and IL-17 production in the cells. Therefore, these data suggested that the spleen CD8α- cDCs are the main DC subsets for induction of S. aureus superantigen-specific immunity.

Correction to: Identification of miRNA-mRNA crosstalk in CD4+ T cells during HIV-1 infection by integrating transcriptome analyses.

An amendment to this paper has been published and can be accessed via the original article.