First mRNA Vaccine and Neutralizing Antibodies Show Promise Against Emerging Bourbon Virus
Key Insights
Researchers have developed the first mRNA vaccine against Bourbon virus (search) (BRBV), encoding the viral envelope glycoprotein (search), which protected against lethal challenge in preclinical models.
Passive transfer of immune serum conferred protection, indicating that antibodies are the primary mechanism driving immunity against this emerging tick-borne pathogen.
Over 50 virus-neutralizing monoclonal antibodies were produced, with both prophylactic and therapeutic administration protecting mice from lethal BRBV challenge.
Researchers have developed the first mRNA vaccine targeting Bourbon virus (search) (BRBV), an emerging tick-borne pathogen with no currently available vaccines or therapeutics. The vaccine, which encodes the viral envelope glycoprotein (search), demonstrated protection against lethal viral challenge in preclinical models, marking a significant step toward countermeasures for this underrecognized threat.
Bourbon virus (search) belongs to the genus Thogotovirus, a group of tick-borne viruses associated with severe and fatal human disease. BRBV is transmitted by the Amblyomma americanum tick, also known as the lone star tick, which is widely distributed throughout the central, eastern, and southern states of the United States. Recent serosurveillance studies indicate that human BRBV infections are more common than previously recorded, highlighting a critical gap in diagnostics and antiviral countermeasures.
mRNA Vaccine Elicits Protective Immunity
The newly developed mRNA vaccine targets the viral envelope glycoprotein (search), a key surface protein involved in viral entry. In preclinical challenge studies, vaccination conferred robust protection against lethal BRBV infection. The research team further demonstrated that passive transfer of immune serum from vaccinated animals to naïve recipients also provided protection, suggesting that antibodies are the main drivers of protective immunity against this virus.
Monoclonal Antibodies as Both Prophylaxis and Therapy
To dissect the antibody response and identify specific viral targets, the investigators produced over 50 different virus-neutralizing monoclonal antibodies. Both prophylactic and therapeutic administration of these antibodies protected mice from a lethal challenge with BRBV. Biochemical and structural characterization of these antibodies is currently ongoing, with the goal of mapping the precise epitopes on the viral envelope protein that mediate neutralization.
These findings collectively demonstrate that targeting the virus envelope protein—whether through vaccination or antibody-based therapy—represents an effective countermeasure strategy against emerging tick-borne viral threats. The work addresses a pressing public health need, as the incidence of tick-borne viral infections continues to rise in the United States and no approved vaccines or therapeutics currently exist for any thogotovirus.