Structure of the human metapneumovirus fusion protein with neutralizing antibody identifies a pneumovirus antigenic site.

Human metapneumovirus and respiratory syncytial virus cause lower respiratory tract infections. The virus fusion (F) glycoprotein promotes membrane fusion by refolding from a metastable pre-fusion to a stable post-fusion conformation. F is also a major target of the neutralizing antibody response. Here we show that a potently neutralizing anti-human metapneumovirus antibody (DS7) binds a structurally invariant domain of F, revealing a new epitope that could be targeted in vaccine development.