Both Neutralizing and Non-Neutralizing Human H7N9 Influenza Vaccine-Induced Monoclonal Antibodies Confer Protection

Area of Science:

• Immunology
• Virology
• Vaccinology

Background:

• Avian influenza H7N9 poses a significant public health risk.
• Development of effective vaccines against H7N9 is ongoing.
• Assessing vaccine-induced antibody responses, including epitope diversity, is crucial.

Purpose of the Study:

• To characterize the binding and functional properties of human antibodies induced by a candidate H7N9 vaccine.
• To identify the epitopes targeted by these vaccine-induced antibodies.
• To understand the protective mechanisms of both neutralizing and non-neutralizing antibodies.

Main Methods:

• Characterization of twelve H7-reactive human monoclonal antibodies.
• In vivo passive transfer challenge experiments in mice.
• Epitope mapping using escape mutant variants of H7 hemagglutinin.

Main Results:

• Both neutralizing and non-neutralizing antibodies conferred protection in a mouse model.
• Unique epitopes on the head and stalk domains of H7 hemagglutinin were identified.
• Non-neutralizing antibodies provided protection via Fc-mediated effector cell recruitment.

Conclusions:

• Vaccine-induced antibodies, including non-neutralizing ones, can be protective against H7N9 avian influenza.
• Fc-mediated mechanisms contribute to the protective efficacy of certain vaccine-induced antibodies.
• Understanding antibody responses to influenza vaccines is essential for developing improved public health strategies.