Oral Pres.: Poliovirus neutralization by nanobody binding

A series of poliovirus-specific nanobodies were raised by immunizing camels with live virus. Nanobodies are small, stable single domains of immune recognition molecules in camelids. The ability of the nanobodies to neutralize poliovirus was tested and the most effective ones were chosen for structural studies. The nanobodies are being studied as possible therapeutic agents. Thus far we have produced cryoEM reconstructionsof two nanobody-poliovirus complexes. Although some of the nanobodies appear to work by saturating the receptor binding sites, the two selected neutralize the virus with much lower than saturating amounts. We observe that the nanonbodies bind in the moiddle of the icosahedral 5-3-3 triangle, just as poliovirus receptor does.