Selection and affinity maturation of human antibodies against rabies virus from a scFv gene library using ribosome display.

We selected useful antibody fragments against rabies virus from a human single chain variable fragment (scFv) gene library using ribosome display technique. The recombinant rabies virus glycoprotein (RVGp) was used as an antigen to isolate specific scFvs. After five rounds of selection, the analysis demonstrated that scFv-ribosome-mRNA complexes were specifically selected against RVGp. Sequence analysis showed that mutations were introduced at random by PCR among the rounds of selection and variants with high affinity were isolated. The obtained scFvs with high affinity could recognize RVGp specifically and showed binding activity to rabies virus. These scFvs were potential for inclusion in a combination of several human monoclonal antibodies (MAbs) aimed for application in rabies post-exposure prophylaxis. Ribosome display technology is a robust tool for rapid isolation of human antibody fragments, and has exceptional strength in affinity maturation and molecular evolution in vitro.