Wuhan Institute of Biological Products Co., Ltd.

Influenza virus epidemics occur annually, posing significant public health challenges. Although anti-influenza drugs are available, newly emerged viral strains frequently develop resistance, necessitating the discovery of new antiviral reagents. This study aims to evaluate the anti-influenza virus activity of Blumea Balsamifera (L.) DC. Extract (BBE) in both in vitro and in vivo settings. The antiviral activity of BBE was assessed using the CellTiter-Glo assay and the cytopathic effect (CPE) assay in Madin-Darby canine kidney (MDCK) cells, targeting influenza virus strains H1N1, H3N2, and four influenza B viruses. Specifically, BBE demonstrated significant inhibition of MDCK cell lesions caused by the A subtypes A/WSN/33 (H1N1) and A/Hong Kong/4801/2014 (H3N2), as well as the B subtypes B/Darwin/58/2019 (Yamagata), B/Phuket/3073/2013 (Yamagata), B/Sichuan Gaoxin/531/2018 (Victoria), and B/Brisbane/60/2008 (Victoria). The extract showed inhibitory concentration (IC50) values of 8.71, 11.38, 10.14, 4.66, 3.17, and 4.29 μg/mL, respectively. Time-of-drug-addition assay results indicated that BBE inhibits the early stages of influenza virus replication. Additionally, in vivo studies in murine models further confirmed the protective effects of BBE, where it reduced viral-induced weight loss, delayed mortality, and mitigated lung tissue damage. These findings suggest that Blumea Balsamifera (L.) DC. extract holds promise as a potential reagent against influenza viruses and warrants further investigation.

Coxsackievirus A16 (CV-A16) is a major pathogen of hand, foot and mouth disease (HFMD). To control HFMD, a CV-A16 vaccine is needed. In this study, the immunogenicity and efficacy of an inactivated CV-A16 vaccine were evaluated in mice. The inactivated CV-A16 vaccine induced effective neutralizing antibodies and T cell responses in BALB/c mice after two doses of intraperitoneal inoculation. The duration of neutralizing antibody and memory B cell persisted for up to 6 months. Four T cell epitopes locating at the VP1 and VP3 were identified for the first time to be CV-A16-specific in mice. A mouse-adapted CV-A16 strain was used to evaluate the efficacy of the CV-A16 vaccine in preventing the death of 14-day-old mice. In an actively immunized-challenged system, the neonatal Kunming mice were intraperitoneally inoculated with the CV-A16 vaccine at doses of 0.1 μg, 0.5 μg or 2.5 μg on days 3 and 9, followed by challenge on day 14. The anti-CV-A16 mouse sera elicited by vaccination showed a high level of neutralizing antibodies against homologous CV-A16 strain. The protective rates of mice immunized with 0.1 μg, 0.5 μg or 2.5 μg vaccine were 90 %, 100 % and 100 %, respectively. In contrast, all mice in the Alum-inoculated group developed paralysis of both hindlimbs and died at 3 days post-challenge, which exhibited high viral loads, severe pathological damages and strong viral protein expression. These results indicated that the inactivated CV-A16 vaccine is promising and that the mouse model will be useful for studying CV-A16 pathogenesis and further evaluation in a multivalent vaccine including the CV-A16 candidate.

The increasing prevalence of mpox calls for the development of safer and more accessible next-generation vaccines. Based on a structure-guided "two-in-one" immunogen design strategy, we have previously developed an innovative protein-based monkeypox virus (MPXV) vaccine, DAM (Double A35 and M1), which addresses the issues of imbalanced bioavailability associated with cocktail vaccines and elicits superior antiviral immunity with a safety profile. In this study, we iteratively designed two "four-in-one" chimeric immunogens, DAM⁺s, using four MPXV antigens, M1, A29, A35, and B6. Although DAM⁺s elicited broader immune responses against four antigens, no additional benefit in either in vitro neutralization or in vivo protection against poxviruses was detected compared to DAM. Notably, vaccination-related tissue damage was observed in the live virus vaccine group, whereas all protein-based vaccines showed better safety and protection against lethal vaccinia virus (VACV) challenge. Together, these further demonstrate that DAM, with a minimal protein subunit of two components, is a promising immunogen to be further clinically developed.