Selection and characterization of scFv antibodies against the Sin Nombre hantavirus nucleocapsid protein

Rodent-borne hantaviruses cause hemorrhagic fever with renal syndrome (HFRS) in the old world and hantavirus cardio-pulmonary syndrome (HCPS) in the new. Most cases of HCPS in North America are caused by Sin Nombre Virus (SNV). Current viral detection technologies depend upon the identification of anti-viral antibodies in patient serum. Detection of viral antigen may facilitate earlier detection of the pathogen. We describe here the characterization of two single-chain Fv antibodies (scFvs), selected from a large naïve phage antibody library, which are capable of identifying the Sin Nombre Virus nucleocapsid protein (SNV-N), with no cross reactivity with the nucleocapsid protein from other hantaviruses. The utility of such selected scFvs was increased by the creation of an scFv-alkaline phosphatase fusion protein which was able to directly detect virally produced material without the need for additional reagents.