Disrupted topological properties of structural brain networks present a glutamatergic neuropathophysiology in people with narcolepsy.

STUDY OBJECTIVES: Growing evidences have documented various abnormalities of the white matter bundles in people with narcolepsy. We sought to evaluate topological properties of brain structural networks, and their association with symptoms and neuropathophysiological features in people with narcolepsy. METHODS: Diffusion tensor imaging was conducted for people with narcolepsy (n = 30) and matched healthy controls as well as symptoms assessment. Structural connectivity for each participant was generated to analyze global and regional topological properties and their correlations with narcoleptic features. Further human brain transcriptome was extracted and spatially registered for connectivity vulnerability. Genetic functional enrichment analysis was performed and further clarified using in vivo emission computed tomography data. RESULTS: A wide and dramatic decrease in structural connectivities was observed in people with narcolepsy, with descending network degree and global efficiency. These metrics were not only correlated with sleep latency and awakening features, but also reflected alterations of sleep macrostructure in people with narcolepsy. Network-based statistics identified a small hyperenhanced subnetwork of cingulate gyrus that was closely related to rapid eye movement sleep behavior disorder (RBD) in narcolepsy. Further imaging genetics analysis suggested glutamatergic signatures were responsible for the preferential vulnerability of connectivity alterations in people with narcolepsy, while additional PET/SPECT data verified that structural alteration was significantly correlated with metabotropic glutamate receptor 5 (mGlutR5) and N-methyl-D-aspartate receptor (NMDA). CONCLUSIONS: People with narcolepsy endured a remarkable decrease in the structural architecture, which was not only closely related to narcolepsy symptoms but also glutamatergic signatures.

Orf virus DNA prime-protein boost strategy is superior to adenovirus-based vaccination in mice and sheep.

Contagious ecthyma (Orf), an acute and highly contagious zoonosis, is prevalent worldwide. Orf is caused by Orf virus (ORFV), which mainly infects sheep/goats and humans. Therefore, effective and safe vaccination strategies for Orf prevention are needed. Although immunization with single-type Orf vaccines has been tested, heterologous prime-boost strategies still need to be studied. In the present study, ORFV B2L and F1L were selected as immunogens, based on which DNA, subunit and adenovirus vaccine candidates were generated. Of note, heterologous immunization strategies using DNA prime-protein boost and DNA prime-adenovirus boost in mice were performed, with single-type vaccines as controls. We have found that the DNA prime-protein boost strategy induces stronger humoral and cellular immune responses than DNA prime-adenovirus boost strategy in mice, which was confirmed by the changes in specific antibodies, lymphocyte proliferation and cytokine expression. Importantly, this observation was also confirmed when these heterologous immunization strategies were performed in sheep. In summary, by comparing the two immune strategies, we found that DNA prime-protein boost strategy can induce a better immune response, which provides a new attempt for exploring Orf immunization strategy.

Oncolytic Parapoxvirus induces Gasdermin E-mediated pyroptosis and activates antitumor immunity.

The advantage of oncolytic viruses (OV) in cancer therapy is their dual effect of directly killing tumours while prompting anti-tumour immune response. Oncolytic parapoxvirus ovis (ORFV) and other OVs are thought to induce apoptosis, but apoptosis, being the immunogenically inert compared to other types of cell death, does not explain the highly inflamed microenvironment in OV-challenged tumors. Here we show that ORFV and its recombinant therapeutic derivatives are able to trigger tumor cell pyroptosis via Gasdermin E (GSDME). This effect is especially prominent in GSDME-low tumor cells, in which ORFV-challenge pre-stabilizes GSDME by decreasing its ubiquitination and subsequently initiates pyroptosis. Consistently, GSDME depletion reduces the proportion of intratumoral cytotoxic T lymphocytes, pyroptotic cell death and the success of tumor ORFV virotherapy. In vivo, the OV preferentially accumulates in the tumour upon systemic delivery and elicits pyroptotic tumor killing. Consequentially, ORFV sensitizes immunologically 'cold' tumors to checkpoint blockade. This study thus highlights the critical role of GSDME-mediated pyroptosis in oncolytic ORFV-based antitumor immunity and identifies combinatorial cancer therapy strategies.

Case report: Overlapping anti-AMPAR encephalitis with anti-IgLON5 disease post herpes simplex virus encephalitis.

Autoimmune encephalitis (AE) is the result of an autoimmune process that occurs as a rapidly advancing encephalopathy. Autoimmune encephalitis was commonly linked to herpes simplex virus 1 (HSV-1) as the most frequently identified virus. The main areas affected by this invasion are the temporal lobe, frontal lobe, and limbic system. Limbic encephalitis is a highly uncommon occurrence involving anti-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR) encephalitis and anti-IgLON family member 5 (IgLON5) disease, both belonging to the rare category. As far as we know, this is the first report showing that a patient diagnosed with AMPAR encephalitis overlapped with anti-IgLON5 disease post herpes simplex virus encephalitis (HSE), which helps to broaden the range of this uncommon autoimmune disease. We recommend autoantibody testing in all patients with HSE, particularly those involving neurological relapses or progression.

A peptide-based vaccine ACP derived from antigens of Mycobacterium tuberculosis induced Th1 response but failed to enhance the protective efficacy of BCG in mice.

BACKGROUND: Tuberculosis (TB) is a global infectious disease, but there is no ideal vaccine against TB except the Bacille Calmette-Guérin (BCG) vaccine. METHODS: Herein, 25 candidate peptides were predicted from four antigens of Mycobacterium tuberculosis based on their high-affinity binding capacity for the human leukocyte antigen (HLA) DRB1∗0101. Three T-helper 1 (Th1) immunodominant peptides (Ag85B12-26, CFP2112-26, and PPE18149-163) were identified by ELISPOT assays in the humanized C57BL/6 mice. They resulted in a novel Th1 peptide-based vaccine ACP named by the first letter of the three peptides. In addition, the protective efficacy was evaluated in humanized or wild-type C57BL/6 mice and the humoral and cellular immune responses were confirmed in vitro. RESULTS: Compared with the PBS group, the ACP vaccinated mice showed slight decreases in colony-forming units (CFUs) and pathological lesions. However, when using it as a booster, the ACP vaccine did not significantly enhance the protective efficacy of BCG in humanized or wild-type mice. Interestingly, we found that ACP vaccination significantly increased the number of interferon-γ positive (IFN-γ+) T lymphocytes and the levels of IFN-γ cytokines as well as antibodies. Furthermore, the IL-2 level was significantly higher in humanized mice prime-boosted with BCG and ACP. CONCLUSIONS: Our results suggested that ACP vaccination could stimulate higher levels of cytokines and antibodies but failed to improve the protective efficacy of BCG in mice, indicating that the secretion level of IFN-γ may not be positively correlated with the protection efficiency of the vaccine. These findings provided important information on the feasibility of a peptide vaccine as a booster for enhancing the protective efficacy of BCG.

Parapoxvirus-based therapy eliminates SARS-CoV-2-loaded fine aerosol and blocks viral transmission in hamster models.

Currently, it is believed that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is an airborne virus, and virus-containing aerosol particles have been found concurrent with the onset of COVID-19, which may contribute to the noncontact transmission of SARS-CoV-2. Exploring agents to block SARS-CoV-2 transmission is of great importance to prevent the COVID-19 pandemic. In this study, we found that inactivated Parapoxvirus ovis (iORFV), a kind of immunomodulator, could compress the proportion of small particle aerosols exhaled by Syrian golden hamsters. Notably, the concentration of SARS-CoV-2 RNA-containing aerosol particles was significantly reduced by iORFV in the early stages after viral inoculation. Importantly, smaller aerosol particles (<4.7 µm) that carry infectious viruses were completely cleared by iORFV. Consistently, iORFV treatment completely blocked viral noncontact (aerosol) transmission. In summary, iORFV may become a repurposed agent for the prevention and control of COVID-19 by affecting viral aerosol exhalation and subsequent viral transmission.

Vesicular stomatitis virus sensitizes immunologically cold tumors to checkpoint blockade by inducing pyroptosis.

BACKGROUND: Traditionally, vesicular stomatitis virus (VSV) and other oncolytic viruses (OVs) are thought to kill tumors by inducing apoptosis. However, cell apoptosis leads to immune quiescence, which is incompatible with the ability of OVs to activate the antitumor immune microenvironment. Thus, studying OVs-mediated oncolytic mechanisms is of great importance for the clinical application of OVs. METHODS: We examined the pyroptosis in tumor cells and tissues by morphological observation, Lactate Dehydrogenase (LDH) assay, frozen section observation, and western-blotting techniques. The critical role of GSDME in VSV-induced pyroptosis was confirmed by CRISPR/Cas9 technique. VSV virotherapy-recruited cytotoxic lymphocytes in the tumors were examined by flow cytometry assay. VSV-activated antitumor immunity was further enhanced by the co-administration with anti-PD-1 antibody. RESULTS: Here, we observed that VSV was able to trigger tumor pyroptosis through Gasdermin E (GSDME) in tumor cells, human tumor samples, and tumor-bearing mouse models. Importantly, the effectiveness of VSV-based virotherapy is highly dependent on GSDME, as depletion of GSDME not only reverses VSV-induced tumor-suppressive effects but also diminishes the ability of VSV to activate antitumor immunity. Notably, VSV treatment makes immunologically 'cold' tumors more sensitive to checkpoint blockade. CONCLUSIONS: Oncolytic VSV induces tumor cell pyroptosis by activating GSDME. GSDME is critical in recruiting cytotoxic T lymphocytes in the context of VSV therapy, which can switch immunologically 'cold' tumors into 'hot' and enhance immune checkpoint therapy efficacy.

A glucose-like metabolite deficient in diabetes inhibits cellular entry of SARS-CoV-2.

The severity and mortality of COVID-19 are associated with pre-existing medical comorbidities such as diabetes mellitus. However, the underlying causes for increased susceptibility to viral infection in patients with diabetes is not fully understood. Here we identify several small-molecule metabolites from human blood with effective antiviral activity against SARS-CoV-2, one of which, 1,5-anhydro-D-glucitol (1,5-AG), is associated with diabetes mellitus. The serum 1,5-AG level is significantly lower in patients with diabetes. In vitro, the level of SARS-CoV-2 replication is higher in the presence of serum from patients with diabetes than from healthy individuals and this is counteracted by supplementation of 1,5-AG to the serum from patients. Diabetic (db/db) mice undergo SARS-CoV-2 infection accompanied by much higher viral loads and more severe respiratory tissue damage when compared to wild-type mice. Sustained supplementation of 1,5-AG in diabetic mice reduces SARS-CoV-2 loads and disease severity to similar levels in nondiabetic mice. Mechanistically, 1,5-AG directly binds the S2 subunit of the SARS-CoV-2 spike protein, thereby interrupting spike-mediated virus-host membrane fusion. Our results reveal a mechanism that contributes to COVID-19 pathogenesis in the diabetic population and suggest that 1,5-AG supplementation may be beneficial to diabetic patients against severe COVID-19.

Mxi1 participates in the progression of lung cancer via the microRNA-300/KLF9/GADD34 Axis.

The purpose of the current study was to define the role of MAX interactor 1 (Mxi1) in the pathogenesis of lung cancer and its underlying molecular mechanism. Bioinformatics analysis was performed to identify important regulatory pathway related to lung cancer. Dual luciferase reporter and ChIP assays were adopted to validate the interaction among Mxi1, miR-300 and KLF9. Loss- and gain-of-function studies were conducted to determine the roles of Mxi1, miR-300, and KLF9 in cell proliferation, migration, and invasion in vitro and their effects on myeloid-derived suppressor cell (MDSC) recruitment in vivo. Mxi1 was poorly expressed in lung cancer tissues and cells and its poor expression was associated with poor prognosis. Mxi1 inhibited miR-300 by suppressing its transcription. miR-300 suppressed the expression of KLF9, and KLF9 negatively regulated GADD34 expression in lung cancer cells. Mxi1 or KLF9 elevation or miR-300 repression inhibited lung cancer cell proliferation, as evidenced by reduced Ki67 and PCNA expression, and lowered invasion and migration. In vivo findings revealed that silencing KLF9 induced tumor growth by enhancing MDSC-mediated immunosuppression through upregulation of GADD34. Collectively, these findings suggest that Mxi1 can inhibit lung cancer progression by regulating the miR-300/KLF9 axis and GADD34-mediated immunosuppression.

A Dual Role of Complement Activation in the Development of Fulminant Hepatic Failure Induced by Murine-Beta-Coronavirus Infection.

With the epidemic of betacoronavirus increasing frequently, it poses a great threat to human public health. Therefore, the research on the pathogenic mechanism of betacoronavirus is becoming greatly important. Murine hepatitis virus strain-3 (MHV-3) is a strain of betacoronavirus which cause tissue damage especially fulminant hepatic failure (FHF) in mice, and is commonly used to establish models of acute liver injury. Recently, MHV-3-infected mice have also been introduced to a mouse model of COVID-19 that does not require a Biosafety Level 3 (BSL-3) facility. FHF induced by MHV-3 is a type of severe liver damage imbalanced by regenerative hepatocellular activity, which is related to numerous factors. The complement system plays an important role in host defense and inflammation and is involved in first-line immunity and/or pathogenesis of severe organ disorders. In this study, we investigated the role of aberrant complement activation in MHV-3 infection-induced FHF by strategies that use C3-deficient mice and intervene in the complement system. Our results showed that mice deficient in C3 had more severe liver damage, a higher viral load in the liver and higher serum concentrations of inflammatory cytokines than wild-type controls. Treatment of C57BL/6 mice with C3aR antagonist or anti-C5aR antibody reduced liver damage, viral load, and serum IFN-γ concentration compared with the control group. These findings indicated that complement system acts as a double-edged sword during acute MHV-3 infection. However, its dysregulated activation leads to sustained inflammatory responses and induces extensive liver damage. Collectively, by investigating the role of complement activation in MHV-3 infection, we can further understand the pathogenic mechanism of betacoronavirus, and appropriate regulation of immune responses by fine-tuning complement activation may be an intervention for the treatment of diseases induced by betacoronavirus infection.

Indocyanine green fluorescence imaging improves the assessment of blood supply of interposition jejunum.

OBJECTIVES: The blood supply of the transposed jejunum was assessed by ICG fluorescence imaging in jejunal interposition, and the correlation with anastomotic leakage or transposed jejunal necrosis was analyzed, aim to explore the value of the application ICG fluorescence imaging technology. METHODS: 84 esophageal reconstructions with jejunal interposition without supercharging were retrospectively analyzed. Intraoperatively, the blood supply of transposed jejunal was observed using ICG fluorescence endoscopy. ROC curve of T1/2 was constructed to calculate the corresponding T1/2max value of the region where the transposed jejunal want to be anastomosed with esophageal stump, the relationship between T1/2max value and anastomotic leakage or transposed jejunal necrosis was analyzed. RESULTS: The occurrence of anastomotic leakage and transposed jejunal necrosis was 9.5%, In the ROC curve, the maximum value of the Youden index was 0.691, the T1/2max value was 5.35 s. When T1/2max value > 5.35 s correspondingly, the probability of anastomotic leakage or transposition jejunal necrosis was 33.3% (7/21); when T1/2max value ≤ 5.35 s, the probability of anastomotic leakage or transposition jejunal necrosis was 1.6% (1/63). The difference between the two groups was statistically significant (P < 0.05). CONCLUSION: ICG fluorescent imaging can effectively assess the blood supply of transposed jejunum. When T1/2max > 5.35, the possibility of the incidence rate of anastomotic leakage or transposed jejunum necrosis increases, this will remind the operators to take corresponding remedial measures during operation.

Establishment of a sheep immortalization cell line for generating and amplifying Orf virus recombinants.

Orf virus (ORFV) causes highly contagious vesiculoulcerative pustular and skin lesions in ruminants like sheep. Developing ORFV-based recombinant vaccine is a potential way to combat Orf disease. Although ORFV could propagate in some kinds of primary cells, the proliferative capacity of primary cells is limited. Therefore, establishing immortalized stable cell line is an effective and affordable way for the production of live ORFV vaccine. In the present study, we introduced a telomerase reverse transcriptase (TERT) gene-expressing cassette into primary ovine fetal turbinate (OFTu) cells, then selected and expanded the cells, which was considered as immortalized OFTu cell line. Our results showed that TERT introduction has successfully expended the lifespan of OFTu cell line over 80 passages, without changing the cellular morphology, affecting chromosomes karyotype and inducing the cellular tumorigenic ability. Immortalized OFTu cell line-derived ORFV has caused similar levels of cytopathic effects (CPE), viral titers and viral particles when compared with the ORFV from primary OFTu cell. Importantly, immortalized OFTu cell line was suitable for generating gene-modified ORFV recombinant through homologous recombination, and for the amplification of ORFV recombinant. In summary, an immortalized OFTu cell line was established and characterized, which could be a powerful tool for preparing ORFV recombinant vaccines.

Long-term stability and protection efficacy of the RBD-targeting COVID-19 mRNA vaccine in nonhuman primates.

Messenger RNA (mRNA) vaccine technology has shown its power in preventing the ongoing COVID-19 pandemic. Two mRNA vaccines targeting the full-length S protein of SARS-CoV-2 have been authorized for emergency use. Recently, we have developed a lipid nanoparticle-encapsulated mRNA (mRNA-LNP) encoding the receptor-binding domain (RBD) of SARS-CoV-2 (termed ARCoV), which confers complete protection in mouse model. Herein, we further characterized the protection efficacy of ARCoV in nonhuman primates and the long-term stability under normal refrigerator temperature. Intramuscular immunization of two doses of ARCoV elicited robust neutralizing antibodies as well as cellular response against SARS-CoV-2 in cynomolgus macaques. More importantly, ARCoV vaccination in macaques significantly protected animals from acute lung lesions caused by SARS-CoV-2, and viral replication in lungs and secretion in nasal swabs were completely cleared in all animals immunized with low or high doses of ARCoV. No evidence of antibody-dependent enhancement of infection was observed throughout the study. Finally, extensive stability assays showed that ARCoV can be stored at 2-8 °C for at least 6 months without decrease of immunogenicity. All these promising results strongly support the ongoing clinical trial.

Screening HLA-A-restricted T cell epitopes of SARS-CoV-2 and the induction of CD8+ T cell responses in HLA-A transgenic mice.

Since severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)-specific T cells have been found to play essential roles in host immune protection and pathology in patients with coronavirus disease 2019 (COVID-19), this study focused on the functional validation of T cell epitopes and the development of vaccines that induce specific T cell responses. A total of 120 CD8+ T cell epitopes from the E, M, N, S, and RdRp proteins were functionally validated. Among these, 110, 15, 6, 14, and 12 epitopes were highly homologous with SARS-CoV, OC43, NL63, HKU1, and 229E, respectively; in addition, four epitopes from the S protein displayed one amino acid that was distinct from the current SARS-CoV-2 variants. Then, 31 epitopes restricted by the HLA-A2 molecule were used to generate peptide cocktail vaccines in combination with Poly(I:C), R848 or poly (lactic-co-glycolic acid) nanoparticles, and these vaccines elicited robust and specific CD8+ T cell responses in HLA-A2/DR1 transgenic mice as well as wild-type mice. In contrast to previous research, this study established a modified DC-peptide-PBL cell coculture system using healthy donor PBMCs to validate the in silico predicted epitopes, provided an epitope library restricted by nine of the most prevalent HLA-A allotypes covering broad Asian populations, and identified the HLA-A restrictions of these validated epitopes using competitive peptide binding experiments with HMy2.CIR cell lines expressing the indicated HLA-A allotype, which initially confirmed the in vivo feasibility of 9- or 10-mer peptide cocktail vaccines against SARS-CoV-2. These data will facilitate the design and development of vaccines that induce antiviral CD8+ T cell responses in COVID-19 patients.

MERS-CoV infection causes brain damage in human DPP4-transgenic mice through complement-mediated inflammation.

The highly pathogenic Middle East Respiratory Syndrome Coronavirus (MERS-CoV) is a severe respiratory virus. Recent reports indicate additional central nervous system (CNS) involvement. In this study, human DPP4 transgenic mice were infected with MERS-CoV, and viral antigens were first detected in the midbrain-hindbrain 4 days post-infection, suggesting the virus may enter the brainstem via peripheral nerves. Neurons and astrocytes throughout the brain were infected, followed by damage of the blood brain barrier (BBB), as well as microglial activation and inflammatory cell infiltration, which may be caused by complement activation based on the observation of deposition of complement activation product C3 and high expression of C3a receptor (C3aR) and C5a receptor (C5aR1) in neurons and glial cells. It may be concluded that these effects were mediated by complement activation in the brain, because of their reduction resulted from the treatment with mouse C5aR1-specific mAb. Such mAb significantly reduced nucleoprotein expression, suppressed microglial activation and decreased activation of caspase-3 in neurons and p38 phosphorylation in the brain. Collectively, these results suggest that MERS-CoV infection of CNS triggers complement activation, leading to inflammation-mediated damage of brain tissue, and regulating of complement activation could be a promising intervention and adjunctive treatment for CNS injury by MERS-CoV and other coronaviruses.

Characterization and structural basis of a lethal mouse-adapted SARS-CoV-2.

There is an urgent need for animal models to study SARS-CoV-2 pathogenicity. Here, we generate and characterize a novel mouse-adapted SARS-CoV-2 strain, MASCp36, that causes severe respiratory symptoms, and mortality. Our model exhibits age- and gender-related mortality akin to severe COVID-19. Deep sequencing identified three amino acid substitutions, N501Y, Q493H, and K417N, at the receptor binding domain (RBD) of MASCp36, during in vivo passaging. All three RBD mutations significantly enhance binding affinity to its endogenous receptor, ACE2. Cryo-electron microscopy analysis of human ACE2 (hACE2), or mouse ACE2 (mACE2), in complex with the RBD of MASCp36, at 3.1 to 3.7 Å resolution, reveals the molecular basis for the receptor-binding switch. N501Y and Q493H enhance the binding affinity to hACE2, whereas triple mutations at N501Y/Q493H/K417N decrease affinity and reduce infectivity of MASCp36. Our study provides a platform for studying SARS-CoV-2 pathogenesis, and unveils the molecular mechanism for its rapid adaptation and evolution.

Large-Sized Graphene Oxide Nanosheets Increase DC-T-Cell Synaptic Contact and the Efficacy of DC Vaccines against SARS-CoV-2.

Dendritic cell (DC) vaccines are used for cancer and infectious diseases, albeit with limited efficacy. Modulating the formation of DC-T-cell synapses may greatly increase their efficacy. The effects of graphene oxide (GO) nanosheets on DCs and DC-T-cell synapse formation are evaluated. In particular, size-dependent interactions are observed between GO nanosheets and DCs. GOs with diameters of >1 µm (L-GOs) demonstrate strong adherence to the DC surface, inducing cytoskeletal reorganization via the RhoA-ROCK-MLC pathway, while relatively small GOs (≈500 nm) are predominantly internalized by DCs. Furthermore, L-GO treatment enhances DC-T-cell synapse formation via cytoskeleton-dependent membrane positioning of integrin ICAM-1. L-GO acts as a "nanozipper," facilitating the aggregation of DC-T-cell clusters to produce a stable microenvironment for T cell activation. Importantly, L-GO-adjuvanted DCs promote robust cytotoxic T cell immune responses against SARS-CoV-2 spike 1, leading to >99.7% viral RNA clearance in mice infected with a clinically isolated SARS-CoV-2 strain. These findings highlight the potential value of nanomaterials as DC vaccine adjuvants for modulating DC-T-cell synapse formation and provide a basis for the development of effective COVID-19 vaccines.

Sensitive and Easy-Read CRISPR Strip for COVID-19 Rapid Point-of-Care Testing.

Rapid and clinically sensitive detection of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) play an important role in the contact tracing and containment of the COVID-19 pandemic. A recently developed field-deployable clustered regularly interspaced short palindromic repeats (CRISPR) detection assay with lateral flow strips shows promise for point-of-care detection of SARS-CoV-2. However, the limit of detection of paper strip-based assays (10-100 copies/µL) is much lower than that of fluorescence-based detection methods. In this study, we developed an easy-readout and sensitive enhanced (ERASE) strip to visualize the results of CRISPR detection and improve the sensitivity to 1 copy/µL with an unambiguous easy-read result. Using 649 clinical samples from blind specimens collected from patients in China, we validated our ERASE assay for SARS-CoV-2 RNA detection with 90.67% positive predictive agreement and 99.21% negative predictive agreement. In conclusion, our study provided a customized CRISPR strip for use in a simple, rapid, ultrasensitive, and highly specific assay for SARS-CoV-2 detection. (Clinical Trial Registration number: 2020-008-01; [2020]IEC(ZD01); PJ-NBEY-2020-009-01; 2020#34).

Peptides-Based Vaccine MP3RT Induced Protective Immunity Against Mycobacterium Tuberculosis Infection in a Humanized Mouse Model.

Background: Tuberculosis (TB) is still a global infectious disease that seriously threatens human beings. The only licensed TB vaccine Bacille Calmette-Guérin (BCG)'s protective efficacy varies significantly among populations and regions. It is very urgent to develop more effective vaccines. Methods: In this study, eleven candidate proteins of Mycobacterium tuberculosis were selected to predict peptides with high-affinity binding capacity for the HLA-DRB1*01:01 molecule. The immunodominant peptides were identified with the enzyme-linked immunospot assay (ELISPOT) and linked in silico to result in a novel polypeptide vaccine in Escherichia coli cells. The vaccine's protective efficacy was evaluated in humanized and wild-type C57BL/6 mice. The potential immune protective mechanisms were explored with Enzyme-linked Immunosorbent Assay (ELISA), flow cytometry, and ELISPOT. Results: Six immunodominant peptides screened from 50 predicted peptides were used to construct a new polypeptide vaccine named MP3RT. After challenge with M. tuberculosis, the colony-forming units (CFUs), lung lesion area, and the number of inflammatory cells in humanized mice rather than wild-type mice vaccinated with MP3RT were significantly lower than these in mice immunized with PBS. The humanized mice vaccinated with MP3RT revealed significant increases in IFN-γ cytokine production, IFN-γ+ T lymphocytes, CD3+IFN-γ+ T lymphocytes, and the MP3RT-specific IgG antibody. Conclusions: Taken together, MP3RT is a promising peptides-based TB vaccine characterized by inducing high levels of IFN-γ and CD3+IFN-γ+ T lymphocytes in humanized mice. These new findings will lay a foundation for the development of peptides-based vaccines against TB.