Through direct cloning and expression of the variable heavy chains (VHHs) of HCAbs from the bone marrow of MERS-CoV infected dromedaries, MERS-CoV specific VHHs or nanobodies were produced. VHH-83 binds with exceptionally high affinity to the receptor binding domain of the viral spike protein. In vitro, this VHH efficiently blocks virus entry at picomolar concentrations

HCAb-83 is a MERS-CoV specific camel/human chimeric heavy chain only antibody (HCAb) - composed of the camel VHH-83 linked to a human Fc domain lacking the CH1 exon Through direct cloning and expression of the variable heavy chains (VHHs) of HCAbs from the bone marrow of MERS-CoV infected dromedaries, MERS-CoV specific VHHs or nanobodies were produced. VHH-83 binds with exceptionally high affinity to the receptor binding domain of the viral spike protein. In vitro, HCAb-83 efficiently blocks virus entry at picomolar concentrations