Circular RNA Vaccines against Monkeypox Virus Provide Potent Protection against Vaccinia Virus Infection in mice.

Since the outbreak of mpox in 2022, widespread concern has been placed on imposing an urgent demand for specific vaccines that offer safer and more effective protection. Using an efficient and scalable circular RNA (circRNA) platform, we constructed four circRNA vaccines that could induce robust neutralizing antibodies as well as T-cell responses by expressing different surface proteins of monkeypox virus (MPXV), resulting in potent protection against vaccinia virus (VACV) in mice. Strikingly, the combination of the four circular RNA vaccines demonstrated the best protection against VACV challenge among all the tested vaccines. Our study provides a favorable approach for developing MPXV-specific vaccines by using a circular mRNA platform and opens up novel avenues for future vaccine research.

Prophylactic efficacy of an intranasal spray with 2 synergetic antibodies neutralizing Omicron.

BACKGROUNDAs Omicron is prompted to replicate in the upper airway, neutralizing antibodies (NAbs) delivered through inhalation might inhibit early-stage infection in the respiratory tract. Thus, elucidating the prophylactic efficacy of NAbs via nasal spray addresses an important clinical need.METHODSThe applicable potential of a nasal spray cocktail containing 2 NAbs was characterized by testing its neutralizing potency, synergetic neutralizing mechanism, emergency protective and therapeutic efficacy in a hamster model, and pharmacokinetics/pharmacodynamic (PK/PD) in human nasal cavity.RESULTSThe 2 NAbs displayed broad neutralizing efficacy against Omicron, and they could structurally compensate each other in blocking the Spike-ACE2 interaction. When administrated through the intranasal mucosal route, this cocktail demonstrated profound efficacy in the emergency prevention in hamsters challenged with authentic Omicron BA.1. The investigator-initiated trial in healthy volunteers confirmed the safety and the PK/PD of the NAb cocktail delivered via nasal spray. Nasal samples from the participants receiving 4 administrations over a course of 16 hours demonstrated potent neutralization against Omicron BA.5 in an ex vivo pseudovirus neutralization assay.CONCLUSIONThese results demonstrate that the NAb cocktail nasal spray provides a good basis for clinical prophylactic efficacy against Omicron infections.TRIAL REGISTRATIONwww.chictr.org.cn, ChiCTR2200066525.FUNDINGThe National Science and Technology Major Project (2017ZX10202203), the National Key Research and Development Program of China (2018YFA0507100), Guangzhou National Laboratory (SRPG22-015), Lingang Laboratory (LG202101-01-07), Science and Technology Commission of Shanghai Municipality (YDZX20213100001556), and the Emergency Project from the Science & Technology Commission of Chongqing (cstc2021jscx-fyzxX0001).

Potent human neutralizing antibodies against Nipah virus derived from two ancestral antibody heavy chains.

Nipah virus (NiV) is a World Health Organization priority pathogen and there are currently no approved drugs for clinical immunotherapy. Through the use of a naïve human phage-displayed Fab library, two neutralizing antibodies (NiV41 and NiV42) targeting the NiV receptor binding protein (RBP) were identified. Following affinity maturation, antibodies derived from NiV41 display cross-reactivity against both NiV and Hendra virus (HeV), whereas the antibody based on NiV42 is only specific to NiV. Results of immunogenetic analysis reveal a correlation between the maturation of antibodies and their antiviral activity. In vivo testing of NiV41 and its mature form (41-6) show protective efficacy against a lethal NiV challenge in hamsters. Furthermore, a 2.88 Å Cryo-EM structure of the tetrameric RBP and antibody complex demonstrates that 41-6 blocks the receptor binding interface. These findings can be beneficial for the development of antiviral drugs and the design of vaccines with broad spectrum against henipaviruses.

A potential bivalent mRNA vaccine candidate protects against both RSV and SARS-CoV-2 infections.

As the world continues to confront severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respiratory syncytial virus (RSV) is also causing severe respiratory illness in millions of infants, elderly individuals, and immunocompromised people globally. Exacerbating the situation is the fact that co-infection with multiple viruses is occurring, something which has greatly increased the clinical severity of the infections. Thus, our team developed a bivalent vaccine that delivered mRNAs encoding SARS-CoV-2 Omicron spike (S) and RSV fusion (F) proteins simultaneously, SF-LNP, which induced S and F protein-specific binding antibodies and cellular immune responses in BALB/c mice. Moreover, SF-LNP immunization effectively protected BALB/c mice from RSV infection and hamsters from SARS-CoV-2 Omicron infection. Notably, our study pointed out the antigenic competition problem of bivalent vaccines and provided a solution. Overall, our results demonstrated the potential of preventing two infectious diseases with a single vaccine and provided a paradigm for the subsequent design of multivalent vaccines.

Deep Parasternal Intercostal Plane Block for Intraoperative Pain Control in Cardiac Surgical Patients for Sternotomy: A Prospective Randomized Controlled Trial.

OBJECTIVES: Sternotomy pain is common after cardiac surgery. The deep parasternal intercostal plane (DPIP) block is a novel technique that provides analgesia to the anterior chest wall. The aim of this study was to investigate the analgesic effect of bilateral DPIP blocks on intraoperative pain control in cardiac surgery. DESIGN: This is a double-blinded, prospective randomized controlled trial (Oct 2020-Dec 2022). SETTINGS: This study was conducted in a single institution, which is an academic university hospital. PARTICIPANTS: Eighty-six elective cardiac surgical patients with median sternotomy were recruited. INTERVENTIONS: Patients were randomly divided into DPIP or control group. Either 20ml 0.25% levobupivacaine or 0.9% normal saline was injected for the DPIP under ultrasound guidance after induction of general anaesthesia. MEASUREMENTS AND MAIN RESULTS: The primary outcome was intraoperative opioids consumption and hemodynamic changes at sternotomy. Secondary outcomes included postoperative morphine consumption, postoperative pain and time to tracheal extubation. Intraoperative opioids requirement was reduced from a median (IQR) intravenous morphine equivalence of 21.4mg (13.8-24.3mg) in control group to 9.5mg (7.3-11.2mg) in the DPIP group (P<0.001). Hemodynamic parameters were more stable in DPIP group at sternotomy, as evidenced by lower percentage increase in systolic, diastolic and mean arterial blood pressure from baseline. No difference was observed in time to tracheal extubation, postoperative morphine consumption, postoperative pain score and spirometry. CONCLUSIONS: Bilateral DPIP block provides effective intraoperative analgesia and opioid-sparing. It may be included as part of the multimodal analgesia for enhanced recovery in cardiac surgery.

Long-term immune response to Omicron-specific mRNA vaccination in mice, hamsters, and nonhuman primates.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) Omicron and its subvariants (such as BQ.1, XBB and the latest variants, including XBB.1.16, EG.5, and BA.2.86), as the dominant variants, currently account for almost all new infections in the world due to their high transmissibility and immune escape ability. Omicron-specific mRNA vaccines showed great potential to protect against Omicron infections. However, whether the vaccine could provide long-term protection is unknown. Toward this goal, we evaluated the immunogenicity of a preclinical Omicron (BA.1)-specific mRNA vaccine (SOmicron-6P) in different animal models. SOmicron-6P induced the highest levels of antibody titers at 1-2 weeks in different animals after the second dose. Even 9 months after the immunization, we observed modest neutralizing activity against Omicron subvariants in macaques. In addition, immunological memory cells can be rapidly reactivated upon stimulation. SOmicron-6P at concentrations higher than 10 µg effectively protected hamsters from BA.1 challenge 253 days after the first immunization, which could be attributed to the reactivation of immune systems. In addition, the toxicity tests conducted in rats revealed a highly favorable biosafety profile for SOmicron-6P, even at high dosages. Our data suggest that the Omicron-specific mRNA vaccine is highly effective and safe in animal models and provides long-term immunologic protection against SARS-CoV-2 Omicron infections.

Both chimpanzee adenovirus-vectored and DNA vaccines induced long-term immunity against Nipah virus infection.

Nipah virus (NiV) is a highly lethal zoonotic paramyxovirus that poses a severe threat to humans due to its high morbidity and the lack of viable countermeasures. Vaccines are the most crucial defense against NiV infections. Here, a recombinant chimpanzee adenovirus-based vaccine (AdC68-G) and a DNA vaccine (DNA-G) were developed by expressing the codon-optimized full-length glycoprotein (G) of NiV. Strong and sustained neutralizing antibody production, accompanied by an effective T-cell response, was induced in BALB/c mice by intranasal or intramuscular administration of one or two doses of AdC68-G, as well as by priming with DNA-G and boosting with intramuscularly administered AdC68-G. Importantly, the neutralizing antibody titers were maintained for up to 68 weeks in the mice that received intramuscularly administered AdC68-G and the prime DNA-G/boost AdC68-G regimen, without a significant decline. Additionally, Syrian golden hamsters immunized with AdC68-G and DNA-G via homologous or heterologous prime/boost immunization were completely protected against a lethal NiV virus challenge, without any apparent weight loss, clinical signs, or pathological tissue damage. There was a significant reduction in but not a complete absence of the viral load and number of infectious particles in the lungs and spleen tissue following NiV challenge. These findings suggest that the AdC68-G and DNA-G vaccines against NiV infection are promising candidates for further development.

Vaccines based on the fusion protein consensus sequence protect Syrian hamsters from Nipah virus infection.

Nipah virus (NiV), a bat-borne paramyxovirus, results in neurological and respiratory diseases with high mortality in humans and animals. Developing vaccines is crucial for fighting these diseases. Previously, only a few studies focused on the fusion (F) protein alone as the immunogen. Numerous NiV strains have been identified, including 2 representative strains from Malaysia (NiV-M) and Bangladesh (NiV-B), which differ significantly from each other. In this study, an F protein sequence with the potential to prevent different NiV strain infections was designed by bioinformatics analysis after an in-depth study of NiV sequences in GenBank. Then, a chimpanzee adenoviral vector vaccine and a DNA vaccine were developed. High levels of immune responses were detected after AdC68-F, pVAX1-F, and a prime-boost strategy (pVAX1-F/AdC68-F) in mice. After high titers of humoral responses were induced, the hamsters were challenged by the lethal NiV-M and NiV-B strains separately. The vaccinated hamsters did not show any clinical signs and survived 21 days after infection with either strain of NiV, and no virus was detected in different tissues. These results indicate that the vaccines provided complete protection against representative strains of NiV infection and have the potential to be developed as a broad-spectrum vaccine for human use.

Ebola virus VP35 perturbs type I interferon signaling to facilitate viral replication.

As one of the deadliest viruses, Ebola virus (EBOV) causes lethal hemorrhagic fevers in humans and nonhuman primates. The suppression of innate immunity leads to robust systemic virus replication of EBOV, leading to enhanced transmission. However, the mechanism of EBOV-host interaction is not fully understood. Here, we identified multiple dysregulated genes in early stage of EBOV infection through transcriptomic analysis, which are highly clustered to Jak-STAT signaling. EBOV VP35 and VP30 were found to inhibit type I interferon (IFN) signaling. Moreover, exogenous expression of VP35 blocks the phosphorylation of endogenous STAT1, and suppresses nuclear translocation of STAT1. Using serial truncated mutations of VP35, N-terminal 1-220 amino acid residues of VP35 were identified to be essential for blocking on type I IFN signaling. Remarkably, VP35 of EBOV suppresses type I IFN signaling more efficiently than those of Bundibugyo virus (BDBV) and Marburg virus (MARV), resulting in stable replication to facilitate the pathogenesis. Altogether, this study enriches understanding on EBOV evasion of innate immune response, and provides insights into the interplay between filoviruses and host.

Duration of humoral immunity from smallpox vaccination and its cross-reaction with Mpox virus.

The ongoing pandemic caused by mpox virus (MPXV) has become an international public health emergency that poses a significant threat to global health. The vaccinia virus Tiantan strain (VTT) was used to vaccinate against smallpox in China 42 years ago. It is urgent to assess the level of immunity to smallpox in individuals vaccinated 43 or more years ago and evaluate their immunological susceptibility to MPXV. Here, we recruited 294 volunteers and detected the level of residual humoral immunity, including the vaccinia-specific IgG level and neutralizing antibody titer, and the cross-antibodies of MPXV A29L, B6R, A35R, and M1R. Our results showed that the humoral immunity from the smallpox vaccine in the population still remains, and VTT-specific NAb levels wane with age. The majority of the population pre-1981 who should be immunized with VTT still maintains certain levels of MPXV-specific antibodies, in particular, targeting A35R and B6R antigens. Furthermore, we separately analyzed the correlations between the OD450 values of VTT-specific IgG and A35R-specific IgG, B6R-specific IgG, and A29L-specific IgG with plasma samples diluted 1:40, showing a linear correlation (p < 0.0001). Our findings suggest that most Chinese populations still maintain VTT-specific IgG antibodies for 42 or more years after smallpox vaccination and could provide some level of protection against MPXV.

An engineered bispecific nanobody in tetrameric secretory IgA format confers broad neutralization against SARS-CoV-1&2 and most variants.

SARS-CoV-2, a type of respiratory virus, has exerted a great impact on global health and economy over the past three years. Antibody-based therapy was initially successful but later failed due to the accumulation of mutations in the spike protein of the virus. Strategies that enable antibodies to resist virus escape are therefore of great significance. Here, we engineer a bispecific SARS-CoV-2 neutralizing nanobody in secretory Immunoglobulin A (SIgA) format, named S2-3-IgA2m2, which shows broad and potent neutralization against SARS-CoV-1, SARS-CoV-2 and its variants of concern (VOCs) including XBB and BQ.1.1. S2-3-IgA2m2 is ∼1800-fold more potent than its parental IgG counterpart in neutralizing XBB. S2-3-IgA2m2 is stable in mouse lungs at least for three days when administrated by nasal delivery. In hamsters infected with BA.5, three intranasal doses of S2-3-IgA2m2 at 1 mg/kg significantly reduce viral RNA loads and completely eliminate infectious particles in the trachea and lungs. Notably, even at single dose of 1 mg/kg, S2-3-IgA2m2 prophylactically administered through the intranasal route drastically reduces airway viral RNA loads and infectious particles. This study provides an effective weapon combating SARS-CoV-2, proposes a new strategy overcoming the virus escape, and lays strategic reserves for rapid response to potential future outbreaks of "SARS-CoV-3".

HBV precore G1896A mutation promotes growth of hepatocellular carcinoma cells by activating ERK/MAPK pathway.

Chronic hepatitis B virus (HBV) infection is one of the leading causes of hepatocellular carcinoma (HCC). The HBV genome is prone to mutate and several variants are closely related to the malignant transformation of liver disease. G1896A mutation (G to A mutation at nucleotide 1896) is one of the most frequently observed mutations in the precore region of HBV, which prevents HBeAg expression and is strongly associated with HCC. However, the mechanisms by which this mutation causes HCC are unclear. Here, we explored the function and molecular mechanisms of the G1896A mutation during HBV-associated HCC. G1896A mutation remarkably enhanced the HBV replication in vitro. Moreover, it increased tumor formation and inhibited apoptosis of hepatoma cells, and decreased the sensitivity of HCC to sorafenib. Mechanistically, the G1896A mutation could activate ERK/MAPK pathway to enhanced sorafenib resistance in HCC cells and augmented cell survival and growth. Collectively, our study demonstrates for the first time that the G1896A mutation has a dual regulatory role in exacerbating HCC severity and sheds some light on the treatment of G1896A mutation-associated HCC patients.

Harringtonine: A more effective antagonist for Omicron variant.

Fusion with host cell membrane is the main mechanism of infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we propose that a new strategy to screen small-molecule antagonists blocking SARS-CoV-2 membrane fusion. Using cell membrane chromatography (CMC), we found that harringtonine (HT) simultaneously targeted SARS-CoV-2 S protein and host cell surface TMPRSS2 expressed by the host cell, and subsequently confirmed that HT can inhibit membrane fusion. HT effectively blocked SARS-CoV-2 original strain entry with the IC50 of 0.217 µM, while the IC50 in delta variant decreased to 0.101 µM, the IC50 in Omicron BA.1 variant was 0.042 µM. Due to high transmissibility and immune escape, Omicron subvariant BA.5 has become the dominant strain of the SARS-CoV-2 virus and led to escalating COVID-19 cases, however, against BA.5, HT showed a surprising effectiveness. The IC50 in Omicron BA.5 was even lower than 0.0019 µM. The above results revealed the effect of HT on Omicron is very significant. In summary, we characterize HT as a small-molecule antagonist by direct targeting on the Spike protein and TMPRSS2.

Developing Next-Generation Protein-Based Vaccines Using High-Affinity Glycan Ligand-Decorated Glyconanoparticles.

Major diseases, such as cancer and COVID-19, are frightening global health problems, and sustained action is necessary to develop vaccines. Here, for the first time, ethoxy acetalated dextran nanoparticles (Ace-Dex-NPs) are functionalized with 9-N-(4H-thieno[3,2-c]chromene-2-carbamoyl)-Siaα2-3Galß1-4GlcNAc (TCC Sia-LacNAc) targeting macrophages as a universal vaccine design platform. First, azide-containing oxidized Ace-Dex-NPs are synthesized. After the NPs are conjugated with ovalbumin (OVA) and resiquimod (Rd), they are coupled to TCC Sia-LacNAc-DBCO to produce TCC Sia-Ace-Dex-OVA-Rd, which induce a potent, long-lasting OVA-specific cytotoxic T-lymphocyte (CTL) response and high anti-OVA IgG, providing mice with superior protection against tumors. Next, this strategy is exploited to develop vaccines against infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein is the main target for neutralizing antibodies. The TCC Sia-Ace-Dex platform is preferentially used for designing an RBD-based vaccine. Strikingly, the synthetic TCC Sia-Ace-Dex-RBD-Rd elicited potent RBD-neutralizing antibodies against live SARS-CoV-2 infected Vero E6 cells. To develop a universal SARS-CoV-2 vaccine, the TCC Sia-Ace-Dex-N-Rd vaccine carrying SARS-CoV-2 nucleocapsid protein (N) is also prepared, which is highly conserved among SARS-CoV-2 and its variants of concern (VOCs), including Omicron (BA.1 to BA.5); this vaccine can trigger strong N-specific CTL responses against target cells infected with SARS-CoV-2 and its VOCs.

A bispecific nanobody dimer broadly neutralizes SARS-CoV-1 & 2 variants of concern and offers substantial protection against Omicron via low-dose intranasal administration.

Current SARS-CoV-2 Omicron subvariants impose a heavy burden on global health systems by evading immunity from most developed neutralizing antibodies and vaccines. Here, we identified a nanobody (aSA3) that strongly cross-reacts with the receptor binding domain (RBD) of both SARS-CoV-1 and wild-type (WT) SARS-CoV-2. The dimeric construct of aSA3 (aSA3-Fc) tightly binds and potently neutralizes both SARS-CoV-1 and WT SARS-CoV-2. Based on X-ray crystallography, we engineered a bispecific nanobody dimer (2-3-Fc) by fusing aSA3-Fc to aRBD-2, a previously identified broad-spectrum nanobody targeting an RBD epitope distinct from aSA3. 2-3-Fc exhibits single-digit ng/mL neutralizing potency against all major variants of concerns including BA.5. In hamsters, a single systemic dose of 2-3-Fc at 10 mg/kg conferred substantial efficacy against Omicron infection. More importantly, even at three low doses of 0.5 mg/kg, 2-3-Fc prophylactically administered through the intranasal route drastically reduced viral RNA loads and completely eliminated infectious Omicron particles in the trachea and lungs. Finally, we discovered that 2(Y29G)-3-Fc containing a Y29G substitution in aRBD-2 showed better activity than 2-3-Fc in neutralizing BA.2.75, a recent Omicron subvariant that emerged in India. This study expands the arsenal against SARS-CoV-1, provides potential therapeutic and prophylactic candidates that fully cover major SARS-CoV-2 variants, and may offer a simple preventive approach against Omicron and its subvariants.

A potent neutralizing antibody provides protection against SARS-CoV-2 Omicron and Delta variants via nasal delivery.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still rapidly spreading worldwide. Many drugs and vaccines have been approved for clinical use show efficacy in the treatment and prevention of SARS-CoV-2 infections. However, the emergence of SARS-CoV-2 variants of concern (VOCs), such as Delta (B.1.617.2) and the recently emerged Omicron (B.1.1.529), has seriously challenged the application of current therapeutics. Therefore, there is still a pressing need for identification of new broad-spectrum antivirals. Here, we further characterized a human antibody (58G6), which we previously isolated from a patient, with a broadly authentic virus-neutralizing activity that inhibits the Delta and Omicron variants with half-maximal inhibitory concentrations (IC50) of 1.69 ng/ml and 54.31 ng/ml, respectively. 58G6 shows prophylactic and therapeutic efficacy in hamsters challenged with the Delta and Omicron variants through nasal delivery. Notably, a very low dosage (2 mg/kg daily) of 58G6 efficiently prevented Omicron variant replication in the lungs. These advantages may overcome the efficacy limitation of currently approved neutralizing antibodies that can be administered only by intravenous injection. In general, 58G6 is a promising prophylactic and therapeutic candidate against current circulating VOCs and even future emerging mutants. To the best of our knowledge, 58G6 is one of the most potent neutralizing antibodies against Omicron, with a broader spectrum than those approved for clinical use. 58G6 could be developed as a nebulized therapy, which would be more cost effective and user friendly and enhance the clinical outcome compared to that obtained with direct nasal delivery.

Hetero-bivalent nanobodies provide broad-spectrum protection against SARS-CoV-2 variants of concern including Omicron.

SARS-CoV-2 variants with adaptive mutations have continued to emerge, causing fresh waves of infection even amongst vaccinated population. The development of broad-spectrum antivirals is thus urgently needed. We previously developed two hetero-bivalent nanobodies (Nbs), aRBD-2-5 and aRBD-2-7, with potent neutralization activity against the wild-type (WT) Wuhan isolated SARS-CoV-2, by fusing aRBD-2 with aRBD-5 and aRBD-7, respectively. Here, we resolved the crystal structures of these Nbs in complex with the receptor-binding domain (RBD) of the spike protein, and found that aRBD-2 contacts with highly-conserved RBD residues and retains binding to the RBD of the Alpha, Beta, Gamma, Delta, Delta plus, Kappa, Lambda, Omicron BA.1, and BA.2 variants. In contrast, aRBD-5 and aRBD-7 bind to less-conserved RBD epitopes non-overlapping with the epitope of aRBD-2, and do not show apparent binding to the RBD of some variants. However, when fused with aRBD-2, they effectively enhance the overall binding affinity. Consistently, aRBD-2-5-Fc and aRBD-2-7-Fc potently neutralized all of the tested authentic or pseudotyped viruses, including WT, Alpha, Beta, Gamma, Delta, and Omicron BA.1, BA.1.1 and BA.2. Furthermore, aRBD-2-5-Fc provided prophylactic protection against the WT and mouse-adapted SARS-CoV-2 in mice, and conferred protection against the Omicron BA.1 variant in hamsters prophylactically and therapeutically, indicating that aRBD-2-5-Fc could potentially benefit the prevention and treatment of COVID-19 caused by the emerging variants of concern. Our strategy provides new solutions in the development of broad-spectrum therapeutic antibodies for COVID-19.