Quantification of vascular endothelial growth factor-C (VEGF-C) by a novel ELISA.

Lymphangiogenesis plays an important role in several normal and pathological conditions such as wound healing, inflammation or metastasis formation in several malignancies. VEGF-C and VEGF-D are important and specific regulatory factors for lymphatic endothelial proliferation and lymphangiogenesis. In order to develop a highly sensitive and specific detection system for VEGF-C, we produced soluble binding proteins and antibodies for a microtiterplate-based assay. Here we describe a specific enzyme-linked immunosorbent assay (ELISA) for the measurement of human, rat and murine VEGF-C. The different antibodies developed against human and rat VEGF-C could be combined to detect processed and partially processed VEGF-C in a specific way. The ELISA was able to detect human and rat VEGF-C with a minimum detection limit of 100 pg/ml. The assay did not show any cross-reactivity with the related protein VEGF-D. Furthermore, complex formation with its soluble receptors VEGFR-2 and VEGFR-3 did not restricted the sensitivity of the assay. Using this assay, VEGF-C was measured in supernatants and lysates of different cell types and in tumour tissue samples of murine, rat and human origin. Cell lines secrete VEGF-C in very low amounts (<1 ng/ml) whereas VEGF-C transfected cells can secrete up to 50 ng/ml VEGF-C into the supernatant. In human tumour tissue samples VEGF-C was detected in some carcinomas in the low protein range. This ELISA will be a useful tool for investigations concerning the physiological function of VEGF-C in lymphangiogenesis under normal and pathophysiological conditions.