THE three-dimensional structure of intact human rhinovirus 14 (HRV-14)
complexed with Fab fragments (Fab17-IA) from a strongly neutralizing
antibody that binds bivalently to the virion(1,2) has been determined
to 4.0 Angstrom resolution by a combination of X-ray crystallography a
nd cryo-electron microscopy. In contradiction to the most commonly hel
d model of antibody-mediated neutralization, Fab17-IA does not induce
a conformational change in the HRV-14 capsid. Instead, the paratope of
the antibody undergoes a large conformational change to accommodate t
he epitope. Unlike any previously described antibody-antigen structure
, the conserved framework region of the antibody makes extensive conta
ct with the viral surface. Fab17-IA penetrates deep within the canyon
in which the cellular receptor for HRV-14 binds(3,4). Hence, it is unl
ikely that viral quaternary structure evolves merely to evade immune r
ecognition, Instead, the shape and position of the receptor-binding re
gion on a virus probably dictates receptor binding and subsequent unco
ating events and has little or no influence on concealing the virus fr
om the immune system.