ABSTRACT
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.
Subject(s)
Neovascularization, Pathologic/therapy , Single-Domain Antibodies/immunology , Vascular Endothelial Growth Factor A/antagonists & inhibitors , Vascular Endothelial Growth Factor A/analysis , Angiogenesis Inhibitors/therapeutic use , Animals , Antibodies, Blocking/immunology , Antibodies, Blocking/therapeutic use , CHO Cells , Camelus , Cell Surface Display Techniques , Cricetinae , Enzyme-Linked Immunosorbent Assay , Human Umbilical Vein Endothelial Cells/drug effects , Human Umbilical Vein Endothelial Cells/immunology , Humans , Nanostructures/therapeutic use , Single-Chain Antibodies/genetics , Single-Chain Antibodies/isolation & purification , Single-Chain Antibodies/therapeutic use , Single-Domain Antibodies/isolation & purification , Single-Domain Antibodies/therapeutic use , Vascular Endothelial Growth Factor A/immunologyABSTRACT
OBJECTIVE: Given the essential role of endothelial progenitor cells (EPCs) in endothelial repair and neovascularization, it is likely that insufficient angiogenesis seen in systemic sclerosis (SSc) is related to EPC alterations. The present study was aimed to analyze in SSc the number of circulating EPCs and their contribution into cardiovascular involvement. METHODS: EPC (CD34+VEGF-R2+ and CD133+VEGF-R2+) circulating levels were evaluated in 40 SSc patients and 24 controls by FACS; their correlations with peripheral vascular manifestations, heart involvement, Framingham risk score, carotid artery disease, endothelial function and morphological signs of microangiopathy were studied. RESULTS: Early stage SSc and high disease activity were accompanied by a rise in circulating EPC levels in association with increased membrane expression of Fas (CD95) that correlated positively with severity of peripheral vascular manifestations. EPC reduction with disease progression was linked with endothelial dysfunction and capillary loss, and showed a strong relation to the development of severe internal organ (predominantly cardiac) involvement and pulmonary hypertension. There was a tendency to decreased EPC levels in SSc pts with low HDL values, but no significant correlations were found between EPCs and Framingham risk factor score, carotid artery IMT and traditional cardiovascular risk factors. CONCLUSIONS: In early stage SSc mobilization of EPCs in response to tissue ischemia was preserved, but dropped with disease progression. EPC reduction may contribute to endothelial dysfunction and impaired angiogenesis, leading to the development of severe vascular life-threatening complications of SSc. Traditional cardiovascular risk factors and subclinical atherosclerosis did not influence EPC levels in SSc patients.
