Structure of parvovirus B19 decorated by Fabs from a human antibody.

Parvovirus B19, one of the most common human pathogens, is a small DNA virus that belongs to the Parvoviridae. As a result of previous infections, antibodies to B19 are present in most adults. B19 has a strong tropism to erythroid progenitor cells and is able to cause a series of medical conditions including fifth disease, arthritis, myocarditis, hydrops fetalis and aplastic crisis. No approved vaccine is currently available for B19 and there is a lack of structural characterization of any B19 epitopes. Here we present the first cryo-EM structure of a B19 virus-like particle (VLP) complexed with the antigen-binding fragment (Fab) of a human neutralizing antibody, 860-55D. A model was built into the 3.2Å resolution map and the antigenic residues on the surface of B19 capsid were identified. Antibody 860-55D bridges the capsid of B19 by binding to a quaternary structure epitope formed by residues from three neighboring VP2 capsid proteins. [ABSTRACT FROM AUTHOR]