Screening of a new candidate coxsackievirus B1 vaccine strain based on its biological characteristics

Area of Science:

• Virology
• Vaccinology
• Infectious Diseases

Background:

• Coxsackievirus B1 (CVB1) is a significant pathogen linked to viral myocarditis, hand, foot, and mouth disease (HFMD), aseptic meningitis, and type 1 diabetes (T1DM).
• Currently, no effective antiviral treatments or preventive vaccines exist for CVB1 infections.

Purpose of the Study:

• To develop a Vero cell-based inactivated Coxsackievirus B1 vaccine candidate.
• To evaluate the immunogenicity and protective efficacy of the candidate vaccine in preclinical models.

Main Methods:

• Isolation of a high-growth CVB1 strain (KM7) in Vero cells.
• Adaptation of KM7 to Vero cells, resulting in vaccine candidate strain KM7-X29 through plaque purification and serial passages.
• Production of an inactivated CVB1 vaccine using the KM7-X29 strain.
• Assessment of neutralizing antibody responses in BALB/c mice and evaluation of maternal antibody-mediated protection in suckling mice against lethal CVB1 challenge.

Main Results:

• The KM7-X29 strain, belonging to the GII sub-genotype (Chinese epidemic strain), achieved high titers (>10^7 CCID50/ml) in Vero cells.
• The inactivated CVB1 vaccine induced a robust neutralizing antibody response in vaccinated mice.
• Maternal antibodies derived from vaccinated mothers conferred 100% protection to suckling mice against lethal CVB1 challenge.

Conclusions:

• The Vero-adapted CVB1 strain KM7-X29 is a promising candidate for developing an inactivated vaccine.
• The developed vaccine candidate elicits effective neutralizing antibodies and maternal protection, warranting further investigation.
• The neonatal murine model is a valuable tool for CVB1 vaccine development research.