Nanoantibodies for detection and blocking of bioactivity of human vascular endothelial growth factor A(165)

Nanoantibodies (single-domain antibodies, nanobodies) derived from noncanonical single-chain immunoglobulins provide an attractive tool for in vitro and in vivo diagnostics as well as for development of targeted drugs for clinical use. Nanoantibodies against several clinically important targets have been developed and are actively investigated. However, no development of nanoantibodies against vascular endothelial growth factor VEGF-A(165) has been reported. We describe here the generation of nanoantibodies derived from single-chain Bactrian camel immunoglobulins directed against VEGF-A(165). We demonstrate that these nanoantibodies are suitable for enzyme-linked immunoassay to quantify human VEGF-A(165) as well as for blocking its activity. Our results provide a basis for diagnostic kit development for quantification of VEGF-A(165), which emerges as a biomarker useful in various pathological conditions. In addition, the nanoantibodies might be used for development of therapeutic molecules targeting VEGF-A(165)-dependent pathological neoangiogenesis.