Rapid assembly of sensitive antigen-capture assays for Marburg virus, using in vitro selection of llama single-domain antibodies, at biosafety level 4.

There is a pressing need for rapid and reliable approaches to the delivery of sensitive yet rugged diagnostic assays specific for emerging viruses, to hasten containment of outbreaks when and wherever they occur. Within 3 weeks, we delivered an antigen-capture assay for Marburg virus (MARV) that was based on llama single-domain antibodies (sdAbs) selected at biosafety level 4. Four unique sdAbs were capable of independently detecting MARV variants Musoke, Ravn, and Angola without cross-reactivity with the 4 Ebola virus species.

Facile generation of heat-stable antiviral and antitoxin single domain antibodies from a semisynthetic llama library.

Llamas possess a class of unconventional immunoglobulins that have only heavy chains; unpaired heavy variable domains are responsible for antigen binding. These domains have previously been cloned and expressed as single domain antibodies (sdAbs); they comprise the smallest known antigen binding fragments. SdAbs have been shown to bind antigens at >90 degrees C and to refold after being denatured.