A novel method to assess antibody-dependent cell-mediated cytotoxicity against influenza A virus M2 in immunized murine models

The matrix protein 2 (M2) is a preferred target for developing a universal vaccine against the influenza A virus (IAV). This study aimed to develop a method for assessing antibody-dependent cell-mediated cytotoxicity (ADCC) associated with M2-based immunization in mice. We first established a stable cell line derived from mouse lymphoma cells (YAC-1) expressing M2 of H3N2. This cell line, designated as YAC-1-M2, was generated using a second-generation lentiviral tricistronic plasmid system to transduce the M2 gene into YAC-1 cells. The ADCC effect induced by polyclonal antibodies targeting matrix protein 2 ectodomain (M2e) was demonstrated by YAC-1-M2 cell lysis by natural killer cells (NK) derived from mice, in the presence of anti-M2 antibodies obtained from mice immunized with an mRNA vaccine based on M2e. This ADCC effect was found to be stronger compared to the effect induced by monoclonal antibodies (14C2) against M2. Moreover, the ADCC effect was enhanced as the effector-to-target ratio of NK to YAC-1-M2 cells increased. In conclusion, we established a novel method to detect ADCC of M2 of IAV, which paves the way for the development of an M2-based universal vaccine against IAV and an in-depth analysis of its mechanism of broad-spectrum immune protection in mice.

mNGS-based dynamic pathogen monitoring for accurate diagnosis and treatment of severe pneumonia caused by fungal infections

Metagenomic next-generation sequencing(mNGs)has been widely applied to identify pathogens associated with infectious diseases.However,limited studies have explored the use of mNGs-based dynamic pathogen monitoring in intensive care unit patients with severe pneumonia.Here,we present a clinical case of an 86-year-old male patient with severe pneumonia caused by a fungal infection.During the clinical treatment,four mNGS analyses were performed within two consecutive weeks.Various respiratory fungal pathogens,including Candida orthopsilosis,Candida albicans,and Aspergillus fumigatus were detected by mNGS of bronchoalveolar lavage fluid(BALF).Based on conventional pathogen identification and clinical symptoms,the patient was diagnosed with severe pneumonia caused by a fungal infection.The abundance of fungal species decreased gradually in response to antifungal and empirical therapies,and the fungal infections were effectively con-trolled.In summary,our results demonstrated that mNGS could effectively identify pathogens in patients with severe pneumonia.Additionally,dynamic pathogen monitoring based on mNGS could assist in the precise diag-nosis of complex infections and may facilitate rapid induction of the most appropriate therapy.

Potential dual outbreak of COVID-19 and HFMD among children in Asia-Pacific countries in the HFMD-endemic area

In the era of the pandemic of coronavirus disease 2019(COVID-19),the severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)infects infants and children with mild or atypical symptoms[1,2].The new variations in SARS-CoV-2 recently found in the United Kingdom greatly increased the risk of infection among children[3].Although previous evidence showed that children rarely developed severe symptoms from COVID-19,the hospitalization rate was 24.5%and the ICU admission rate was 2.5%among children in the United States[4].Further,there is a lack of evidence regarding the influence of the recently appeared SARS-CoV-2 variations.Thus,it is of great significance to monitor and track the COVID-19 infection among children.