Nasal Spray of Neutralizing Monoclonal Antibody 35B5 Confers Potential Prophylaxis Against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Variants of Concern (VOCs): A Small-scale Clinical Trial.

BACKGROUND: SARS-CoV-2 VOCs, especially the Delta and Omicron variants, have been reported to show significant resistance to approved neutralizing monoclonal antibodies (mAbs) and vaccines. We previously identified a mAb named 35B5 that harbors broad neutralization to SARS-CoV-2 VOCs. Herein, we explored the protection efficacy of a 35B5-based nasal spray against SARS-CoV-2 VOCs in a small-scale clinical trial. METHODS: We enrolled 30 healthy volunteers who were nasally administrated with the modified 35B5 formulation. At 12, 24, 48 and 72 hours after nasal spray, the neutralization efficacy of nasal mucosal samples was assayed with pseudoviruses coated with SARS-CoV-2 Spike protein of the wild-type (WT), Alpha, Beta, Delta, or Omicron variants. RESULTS: The nasal mucosal samples collected within 24 hours after nasal spray effectively neutralized SARS-CoV-2 VOCs (including Delta and Omicron). Meanwhile, the protection efficacy was 60% effective and 20% effective at 48 and 72 hours after nasal spray, respectively. CONCLUSIONS: A single nasal spray of 35B5 formation conveys 24-hour effective protection against SARS-CoV-2 VOCs, including the Alpha, Beta, Delta, or Omicron variants. Thus, 35B5 nasal spray might be potential in strengthening SARS-CoV-2 prevention, especially in the high-risk population.

The Differentiation and Maintenance of SARS-CoV-2-Specific Follicular Helper T Cells.

Upon acute viral infection, virus-specific CD4+ T cells differentiate into either TH1 cells or follicular helper T (TFH) cells. The molecular pathways governing such bimodal cell fate commitment remain elusive. Additionally, effector virus-specific TFH cells further differentiate into corresponding memory population, which confer long-term protection against re-infection of same viruses by providing immediate help to virus-specific memory B cells. Currently, the molecular mechanisms underlying the long-term maintenance of memory TFH cells are largely unknown. In this review, we discuss current understanding of early differentiation of virus-specific effector TFH cells and long-term maintenance of virus-specific memory TFH cells in mouse models of viral infection and patients of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

The Differentiation and Maintenance of SARS-CoV-2-Specific Follicular Helper T Cells

Upon acute viral infection, virus-specific CD4+ T cells differentiate into either TH1 cells or follicular helper T (TFH) cells. The molecular pathways governing such bimodal cell fate commitment remain elusive. Additionally, effector virus-specific TFH cells further differentiate into corresponding memory population, which confer long-term protection against re-infection of same viruses by providing immediate help to virus-specific memory B cells. Currently, the molecular mechanisms underlying the long-term maintenance of memory TFH cells are largely unknown. In this review, we discuss current understanding of early differentiation of virus-specific effector TFH cells and long-term maintenance of virus-specific memory TFH cells in mouse models of viral infection and patients of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection.

Sensitivity of SARS-CoV-2 Variants to Neutralization by Convalescent Sera and a VH3-30 Monoclonal Antibody.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a global pandemic of novel coronavirus disease (COVID-19). Though vaccines and neutralizing monoclonal antibodies (mAbs) have been developed to fight COVID-19 in the past year, one major concern is the emergence of SARS-CoV-2 variants of concern (VOCs). Indeed, SARS-CoV-2 VOCs such as B.1.1.7 (UK), B.1.351 (South Africa), P.1 (Brazil), and B.1.617.1 (India) now dominate the pandemic. Herein, we found that binding activity and neutralizing capacity of sera collected from convalescent patients in early 2020 for SARS-CoV-2 VOCs, but not non-VOC variants, were severely blunted. Furthermore, we observed evasion of SARS-CoV-2 VOCs from a VH3-30 mAb 32D4, which was proved to exhibit highly potential neutralization against wild-type (WT) SARS-CoV-2. Thus, these results indicated that SARS-CoV-2 VOCs might be able to spread in convalescent patients and even harbor resistance to medical countermeasures. New interventions against these SARS-CoV-2 VOCs are urgently needed.

A novel strategy for the detection of SARS-CoV-2 variants based on multiplex PCR-MALDI-TOF MS (preprint)

Background The second wave of coronavirus disease 2019 (COVID-19) has been incessantly causing catastrophe worldwide, and the emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants causes further uncertainty regarding epidemic risk. Here, a novel strategy for the detection of SARS-CoV-2 variants using multiplex PCR coupled with MALDI-TOF MS was developed. Methods Plasmids carrying gene sequences containing 9 mutation types in 7 mutated sites (HV6970del, N501Y, K417N, P681H, D614G, E484K, L452R, E484Q and P681R) in the receptor-binding domain of the spike protein of SARS-CoV-2 variants were synthesized. Using the nucleic acid sequence of SARS-CoV-2 nonvariant and a synthetic SARS-CoV-2-variant-carrying plasmid, a MALDI-TOF MS method based on the single-base mass probe extension of multiplex PCR amplification products was established to detect the above nine mutation types. The detection limit of this method was determined via the concentration gradient method. Twenty-one respiratory tract pathogens (9 bacteria, 11 respiratory viruses) and pharyngeal swab nucleic acid samples from healthy people were selected for specific validation. Sixteen samples from COVID-19 patients were used to verify the accuracy of this method. Results The 9 mutation types could be detected simultaneously by triple PCR amplification coupled with MALDI-TOF MS. SARS-CoV-2 and all six variants (B.1.1.7, B.1.351, B.1.429, B.1.526, P.1 and B.1.617) could be identified. The detection limit for all 9 sites was 1.5×10 3 copies. The specificity of this method was 100%, and the accuracy of real-time PCR CT values less than 30 among positive samples was 100%. This method is open and extensible, and can be used in a high-throughput manner, easily allowing the addition of new mutation sites as needed to identify and track new SARS-CoV-2 variants as they emerge. Conclusions Multiplex PCR-MALDI-TOF MS provides a new detection option with practical application value for SARS-CoV-2 and its variant infection. Key point An all-in-one SARS-CoV-2 variant identification method based on a multiplex PCR-MALDI-TOF MS system was developed. All of the SARS-CoV-2 variants can be identified based on 9 types of 7 mutated sites of RBD of spike protein using this method.

The lncRNA Snhg1-Vps13D vesicle trafficking system promotes memory CD8 T cell establishment via regulating the dual effects of IL-7 signaling.

The efficient induction and long-term persistence of pathogen-specific memory CD8 T cells are pivotal to rapidly curb the reinfection. Recent studies indicated that long-noncoding RNAs expression is highly cell- and stage-specific during T cell development and differentiation, suggesting their potential roles in T cell programs. However, the key lncRNAs playing crucial roles in memory CD8 T cell establishment remain to be clarified. Through CD8 T cell subsets profiling of lncRNAs, this study found a key lncRNA-Snhg1 with the conserved naivehi-effectorlo-memoryhi expression pattern in CD8 T cells of both mice and human, that can promote memory formation while impeding effector CD8 in acute viral infection. Further, Snhg1 was found interacting with the conserved vesicle trafficking protein Vps13D to promote IL-7Rα membrane location specifically. With the deep mechanism probing, the results show Snhg1-Vps13D regulated IL-7 signaling with its dual effects in memory CD8 generation, which not just because of the sustaining role of STAT5-BCL-2 axis for memory survival, but more through the STAT3-TCF1-Blimp1 axis for transcriptional launch program of memory differentiation. Moreover, we performed further study with finding a similar high-low-high expression pattern of human SNHG1/VPS13D/IL7R/TCF7 in CD8 T cell subsets from PBMC samples of the convalescent COVID-19 patients. The central role of Snhg1-Vps13D-IL-7R-TCF1 axis in memory CD8 establishment makes it a potential target for improving the vaccination effects to control the ongoing pandemic.

Detection of SARS-CoV-2 nucleic acid in CSF by ultrahigh depth sequencing in a patient with COVID-19 and neurological dysfunction: a case report (preprint)

Background: SARS-Coronavirus-2 (SARS-CoV-2), the pathogen of coronavirus disease 2019 (COVID-19), not only infects the respiratory tract, but also other organs. About a third of the inpatients of COVID-19 have neurological symptoms and in vitro experiments revealed that SARS-CoV-2 could infect human neural progenitor cells and brain organoids. However, the traditional test often reports negative owing to the low number of virus in the cerebrospinal fluid. To date, timely diagnosis of central nervous system infection of SARS-CoV-2 remains a challenge.Case presentation: On day 14 of COVID-19, seizures, maxillofacial convulsions, intractable hiccups and significant increase in intracranial pressure developed in a 56-year-old man. The RT-PCR of SARS-CoV-2 was negative. SARS-CoV-2 nucleic acid were detected in cerebrospinal fluid (CSF) by ultrahigh depth sequencing. The patient was successfully treated after 14 days of mechanical ventilation and treatment of pneumonia and neurological dysfunction.Conclusions: This case suggests SARS-CoV-2 can invade the central nervous system and relevant examinations with CSF including ultrahigh depth sequencing of SARS-CoV-2 are needed among COVID-19 patients with neurological dysfunction.