Cellular and Humoral Immune Profiles After Hepatitis E Vaccination and Infection.

Area of Science:

• Immunology
• Vaccinology
• Hepatitis Research

Background:

• Hepatitis E virus (HEV) poses a significant global health burden, with notable impact on vulnerable groups.
• The recombinant HEV239 vaccine (Hecolin®) shows efficacy, but detailed human cellular immune responses require further investigation.
• Understanding immune responses is crucial for optimizing vaccination strategies in HEV-endemic areas.

Purpose of the Study:

• To characterize the humoral and cellular immune responses induced by the HEV239 vaccine in healthy Bangladeshi women.
• To compare vaccine-induced immune responses with those following natural HEV infection.
• To assess the durability of antibody responses following HEV239 vaccination.

Main Methods:

• Dual IFNγ and IL-4 ELISpot assays were employed to measure cellular immune responses.
• Humoral immune responses were assessed through longitudinal antibody level measurements.
• Participants included healthy Bangladeshi women aged 16-39 years, vaccinated with HEV239 or naturally infected with HEV.

Main Results:

• Robust, predominantly Th1-mediated cellular immune responses were observed 30 days post-third HEV239 vaccine dose.
• Vaccine-induced cellular responses were comparable to those observed during acute natural HEV infection.
• Sustained antibody production against HEV genotypes 1 and 3 E2 domain persisted for up to two years post-vaccination.

Conclusions:

• HEV239 vaccination induces a strong and comparable cellular immune response to natural HEV infection.
• The vaccine promotes sustained antibody production, indicating long-term immunogenicity.
• Findings support the potential for broader application of HEV239 in HEV-endemic regions.