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Severe influenza A virus (IAV) infection is associated with immune dysfunction. Here, we show circulating CD8 + T-cell profiles from patients hospitalized with avian H7N9, seasonal IAV, and influenza vaccinees. Patient survival reflects an early, transient prevalence of highly activated CD38 + HLA-DR + PD-1 + CD8 + T cells, whereas the prolonged persistence of this set is found in ultimately fatal cases. Single-cell T cell receptor (TCR)-αβ analyses of activated CD38 + HLA-DR + CD8 + T cells show similar TCRαβ diversity but differential clonal expansion kinetics in surviving and fatal H7N9 patients. Delayed clonal expansion associated with an early dichotomy at a transcriptome level (as detected by single-cell RNAseq) is found in CD38 + HLA-DR + CD8 + T cells from patients who succumbed to the disease, suggesting a divergent differentiation pathway of CD38 + HLA-DR + CD8 + T cells from the outset during fatal disease. Our study proposes that effective expansion of cross-reactive influenza-specific TCRαβ clonotypes with appropriate transcriptome signatures is needed for early protection against severe influenza disease. Virus-specific CD8 + T cells are crucial during H7N9 influenza infection, but CD8 + T cell dysfunction is associated with poor prognosis. Here, the authors use molecular and phenotypic analysis to establish persistence of clonally diverse CD8 + T cell populations during fatal infection.

The understanding of protective immunity during HIV infection remains elusive. Here we showed that CD160 defines a polyfunctional and proliferative CD8+ T cell subset with a protective role during chronic HIV-1 infection. CD160+ CD8+ T cells derived from HIV+ patients correlated with slow progressions both in a cross-sectional study and in a 60-month longitudinal cohort, displaying enhanced cytotoxicity and proliferative capacity in response to HIV Gag stimulation; triggering CD160 promoted their functionalities through MEK-ERK and PI3K-AKT pathways. These observations were corroborated by studying chronic lymphocytic choriomeningitis virus (LCMV) infection in mice. The genetic ablation of CD160 severely impaired LCMV-specific CD8+ T cell functionalities and thereby resulted in loss of virus control. Interestingly, transcriptional profiling showed multiple costimulatory and survival pathways likely to be involved in CD160+ T cell development. Our data demonstrated that CD160 acts as a costimulatory molecule positively regulating CD8+ T cells during chronic viral infections, thus representing a potential target for immune intervention.

The NOD-like receptors (NLRs) have been shown to be involved in infection and autoinflammatory disease. Previously, we identified a zebrafish NLR, nlrc3-like , required for macrophage homeostasis in the brain under physiological conditions. Here, we found that a deficiency of nlrc3-like leads to decreased bacterial burden at a very early stage of Mycobacterium marinum infection, along with increased production of pro-inflammatory cytokines, such as il-1β and tnf-α . Interestingly, myeloid-lineage specific overexpression of nlrc3-like achieved the opposite effects, suggesting that the impact of nlrc3-like on the host anti-mycobacterial response is mainly due to its expression in the innate immune system. Fluorescence-activated cell sorting (FACS) and subsequent gene expression analysis demonstrated that inflammasome activation-related genes were upregulated in the infected macrophages of nlrc3-like deficient embryos. By disrupting asc , encoding apoptosis-associated speck-like protein containing a CARD, a key component for inflammasome activation, the bacterial burden increased in asc and nlrc3-like double deficient embryos compared with nlrc3-like single deficient embryos, implying the involvement of inflammasome activation in infection control. We also found extensive neutrophil infiltration in the nlrc3-like deficient larvae during infection, which was associated with comparable bacterial burden but increased tissue damage and death at a later stage that could be alleviated by administration of dexamethasone. Our findings uncovered an important role of nlrc3-like in the negative regulation of macrophage inflammasome activation and neutrophil infiltration during mycobacterial infection. This highlights the importance of a balanced innate immune response during mycobacterial infection and provides a potential molecular basis to explain how anti-inflammatory drugs can improve treatment outcomes in TB patients whose infection is accompanied by a hyperinflammatory response.

PurposeThe aim of this study was to determine the expression of Glypican-3(GPC-3) and AXL in hepatocellular carcinomas (HCCs).MethodsA total of 140 patients diagnosed with HCC were included in this study. All patients had undergone radical surgery and had complete clinical information. Formalin-fixed paraffin-embedded tissue blocks of HCC from these patients were collected, and the expression levels of GPC-3 and AXL were detected by immunohistochemical (IHC) staining.ResultsImmunohistochemical analysis showed that GPC-3 and AXL were diffusely expressed in HCCs. The positive expression rate of GPC-3 was 77.1% (108/140) and that of AXL was 85.7% (120/140). Additionally, the proportion of cases with positive expression for either GPC-3 or AXL is 93.6%.ConclusionsThe findings of this study confirm that both GPC-3 and AXL are highly expressed in HCCs tissues, and the high co-expression rate supports the development of dual-target chimeric antigen receptor T (CAR-T) cell therapy for HCC treatment.

It remains poorly defined whether any human miRNAs play protective roles during HIV infection. Here, focusing on a unique cohort of HIV-infected former blood donors, we identified miR-31 (hsa-miR-31) by comparative miRNA profiling as the only miRNA inversely correlating with disease progression. We further validated this association in two prospective cohort studies. Despite conservation during evolution, hsa-miR-31, unlike its mouse counterpart (mmu-miR-31), was downregulated in human T cell upon activation. Our ex vivo studies showed that inhibiting miR-31 in naïve CD4+ T cells promoted a transcriptional profile with activation signature. Consistent with this skewing effect, miR-31 inhibition led to remarkably increased susceptibility to HIV infection. The suppressive nature of miR-31 in CD4+ T cell activation was pinpointed to its ability to decrease T-bet, the key molecule governing IFN-γ production and activation of CD4+ T cells, by directly targeting the upstream STAT1 transcriptional factor for downregulation, thus blunting Th1 response. Our results implicated miR-31 as a useful biomarker for tracking HIV disease progression and, by demonstrating its importance in tuning the activation of CD4+ T cells, suggested that miR-31 may play critical roles in other physiological contexts where the CD4+ T cell homeostasis needs to be deliberately controlled.

Toll-like receptors (TLRs) are important pattern recognition receptor(s) known to mediate the sensing of invading pathogens and subsequent immune responses. In this study, we investigate whether TLRs could be explored for the preparation of human CD8 + T cell products used in adoptive cell therapy (ACT). Following characterization of TLRs expression on human CD8 + T cells, we screened TLR-specific agonists for their ability to act in concert with anti-CD3 to stimulate the proliferation of these cells and corroborated the observed co-stimulatory effect by transcriptional profiling analyses. Consequently, we developed an optimal formulation for human CD8 + T cell amplification by combining CD3/CD28 antibody, interleukin 7 (IL-7), interleukin 15 (IL-15), and three agonists respectively targeting TLR1/2, TLR2/6, and TLR5. This new formulation performed better in amplifying PD-1+CD8 + T cells, a potential repertoire of tumor-reactive CD8 + T cells, from tumor patients than the conventional formulation. Importantly, the expanded CD8 + T cells showed restored functionality and consequently a robust anti-tumor activity in an in vitro co-culturing system. Together, our study established the utility of TLR agonists in ex vivo expansion of tumor-targeting CD8 + T cells, thus providing a new avenue toward a more effective ACT.

To curb the pandemic of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), multiple platforms have been employed toward a safe and highly effective vaccine. Here, we develop a novel cell-based vaccine candidate, namely K562-S, by utilizing human cell K562 as a cellular carrier to display Spike (S) protein of SARS-CoV-2 on the membrane. Analogous to the traditional inactivated vaccine, K562-S cells can be propagated to a large scale by culturing and completely lose their viability after exposure to X-ray irradiation or formalin. We in turn demonstrated high immunogenicity of formalin-inactivated K562-S vaccine in both mouse and non-human primates and its protective efficacy in mice. In mice, immunization with inactivated K562-S vaccines can elicit potent neutralizing antibody (nAb) responses persisting longer than 5 months. We consequently showed in a hACE2 mouse model of SARS-CoV-2 infection that a two-shot vaccination with adjuvanted K562-S rendered greater than 3 log reduction in viral lung load and concomitant ameliorated lung pathology. Of importance, the administration of the same regimen in non-human primates was able to induce a neutralizing antibody titer averaging three-fold higher relative to human convalescent serum. These results together support the promise of K562-based, S-protein-expressing vaccines as a novel vaccination approach against SARS-CoV-2. Importantly, with a powerful capacity to carry external genes for cell-based vectors, this platform could rapidly generate two- and multiple-valent vaccines by incorporating SARS-CoV-2 mutants, SARS-CoV, or MERS-CoV.

In recent years, the prevalence of HIV-1 infection has been rapidly increasing among men who have sex with men (MSM). However, it remains unknown how the host immune system responds to the infection in this population. We assessed the quantity of HIV-specific CD8(+) T-cell responses by using Elispot assay and their functionalities by measuring 5 CD8(+) T-cell evaluations (IL-2, MIP-1β, CD107a, TNF-α, IFN-γ) with flow cytometry assays among 18 primarily and 37 early chronically HIV-infected MSM. Our results demonstrated that subjects at early chronic phase developed HIV-specific CD8(+) T-cell responses with higher magnitudes and more diversified functionalities in comparison with those at primary infection. However, populations with IL-2(+) CD107a(+) or in combination with other functionality failed to develop in parallel. The multifunctional but not monofunctional HIV-specific CD8(+) T cells were associated with higher CD4(+) T -cell counts and lower viral loads. These data revealed that prolonged infection from primary to early chronic infection could selectively increase the functionalities of HIV-specific CD8(+) T cells in HIV-infected MSM population, the failure to develop IL-2 and cytotoxic functionalities in parallel may explain why the increased HIV-specific CD8(+) T cells were unable to enhance the containment of HIV-1 replication at the early chronic stage.

Few studies on the humoral immune responses in human during natural influenza infection have been reported. Here, we used serum samples from pandemic 2009 H1N1 influenza infected patients to characterize the humoral immune responses to influenza during natural infection in humans. We observed for the first time that the pandemic 2009 H1N1 influenza induced influenza A-specific IgM within days after symptoms onset, whereas the unit of IgG did not changed. The magnitude of influenza A-specific IgM antibodies might have a value in predicting the rate of virus clearance to some degree. However, the newly developed IgM was not associated with hemagglutination inhibition (HI) activities in the same samples but correlated with HI activities of subsequently collected sera which were mediated by IgG antibodies, indicating that IgM was critical for influenza infection and influences subsequent IgG antibody responses. These findings provide new important insights on the human immunity to natural influenza infection.

The avian origin A/H7N9 influenza virus causes high admission rates (>99%) and mortality (>30%), with ultimately favourable outcomes ranging from rapid recovery to prolonged hospitalization. Using a multicolour assay for monitoring adaptive and innate immunity, here we dissect the kinetic emergence of different effector mechanisms across the spectrum of H7N9 disease and recovery. We find that a diversity of response mechanisms contribute to resolution and survival. Patients discharged within 2–3 weeks have early prominent H7N9-specific CD8 + T-cell responses, while individuals with prolonged hospital stays have late recruitment of CD8 + /CD4 + T cells and antibodies simultaneously (recovery by week 4), augmented even later by prominent NK cell responses (recovery >30 days). In contrast, those who succumbed have minimal influenza-specific immunity and little evidence of T-cell activation. Our study illustrates the importance of robust CD8 + T-cell memory for protection against severe influenza disease caused by newly emerging influenza A viruses. H7N9 avian influenza viruses can cause severe human disease. Here, the authors analyse blood samples from hospitalized H7N9 patients and show that a diversity of immune mechanisms seem to influence disease length and outcome.