Lymphangiogenesis has traditionally been overshadowed by the greater emphasis placed on the blood vascular system (angiogenesis). This is due in part to the lack of identification of lymphangiogenic factors, as well as suitable markers that distinguish blood from lymphatic vascular endothelium. Recently, novel growth factors, receptors, cell surface proteins, and transcription factors have been found which play a role in the lymphatic endothelium. These are VEGF-C, VEGF-D, VEGFR-3, LYVE-1, Podoplanin, and Prox-1. Especially the transcription factor Prox-1 and the two transmembrane receptors Podoplanin and LYVE-1 are described as specific markers for lymphatic endothelial cells.

In this respect we are pleased to announce that we have developed a rabbit polyclonal antibody against the extracellular domain of human and mouse LYVE-1.

The antigen-affinity purified anti-human LYVE-1 antibody (Cat# 102-PA50AG) works very well in IHC on formalin-fixed paraffin-embedded sections of human intestinal tissue (border area of a colon carcinoma) (Fig.1) The Protein-A purified anti-human LYVE-1 (Cat# 102-PA50S, Cat# 102-PA50) is suitable for staining with cryo sections (Fig.2).

The Protein-A purified anti-mouse LYVE-1antibody (Cat# 103-PA50S / Cat# 103-PA50) works very well in the IHC on frozen sections (Fig.3) Results in IHC on cryo sections of colon tissue with the same antibody (Fig.4). The antigen-affinity purified antibody (Cat# 103-PA50AG)  is also working on formalin-fixed paraffin-embedded sections of mouse intestine (Fig.5). 

Prox1: A reliable marker for lymphatic endothelial cells 

The ability to discriminate reliably at the histological level between blood and lymphatic capillaries would greatly assist the study of a number of biological and pathological questions and may also be of clinical utility.

In this respect we are pleased to announce that we now have available a polyclonal antibody against Prox1 shown to be a very specific and reliable marker for the lymphatics (Fig.1).

The RELIDA (Receptor-Ligand-Detection-Assay) / BioLISA was a novel kind of ELISA based not on a antibody but on a soluble receptor (Cat# DA-066). This system has two important advantages: (1) only bioactive ligands able to bind to the receptor are detectable and (2) having the appropriate antibodies all ligands binding to the used soluble receptor can be measured. So, using sVEGFR-1 as capture receptor you would be able to measure the amount of bioactive VEGF-A and -B as well as PlGF (More!).

We now are pleased to announce that we in collaboration with Bender MedSystems (Vienna, Austria) also offer a highly sensitive and specific Sandwich-ELISA (Cat# DA-068) for the quantitative measurement of total human VEGF-A (all isoforms)!

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.

In this respect we are pleased to announce that in collaboration with Bender MedSystems (Vienna, Austria) a highly sensitive and specific ELISA for the quantitative measurements of human, rat and murine VEGF-C is now available (Cat# DA-070; Cat# DA-074). First results using this ELISA for the measurement of VEGF-C in supernatants and lysates of different cell types and in tumour tissue samples of murine, rat and human origin are published by Weich et al., (J Immunol Methods. 2004 Feb 15;285(2):145-55).

The availability of larger amounts of proteins by recombinant expression und purification simplifies the analyses for protein structure and function. For purification several strategies have been developed in particular the expression as fusion protein for an efficient application of the affinity chromatography.
In the last couple of years many peptide sequences/epitopes for the purification of recombinant proteins have been established. These so-called “tags” can be used e.g. to determine the cellular localization or to quantify proteins. The polyhistidine “tag” (His-tag) is the most used affinity epitope for the purification of recombinant proteins [1]. Proteins with a polyhistidine tag (e.g. 6xHis or 8xHis) can be purified in one step using a metal-chelate column (e.g. Ni2+, Zn2+, Cu2+ or Co2+) and imidazole as eluent. This method now is a very attractive system for the purification of larger amounts proteins for structural and functional studies. So far His-tagged proteins were successfully purified from different expression systems like E. coli, yeast, insect cells and plant cells [1,2]. An important requirement beside the efficient and robust purification method is the availability of a fast detection system for checking the purification steps of these His-tagged proteins if no specific antibody is available.

In this respect we are pleased to announce that we have developed a very specific and unique rabbit polyclonal antibody against the His-tag [Cat#102-PA80] suitable for detection of His-tagged proteins in the Western analysis and ELISA [3]. The antibody was generated by immunizing rabbits with highly purified His-tagged proteins expressed in insect cells. The anti-His-tag antibodies were then purified from sera by an antigen-affinity chromatography using a His-peptide as matrix. Western analysis with several His-tagged proteins either expressed in insect cells or E. coli showed that the antibody recognizes all tested proteins fused to a C-terminal but not to a N-terminal His-tag. This antibody might be a very good tool to test supernatants or cell lysates for expression of recombinant proteins. For Western analysis the antibody can be used at very low concentration, e.g. at 0.1µg/ml (Fig.1). 

Literature: 1. Terpe K, Appl. Micrbiol. Biotechnol. 60:523, 2003; 2. Leelavathi et al, Molecular Breeding 11:49, 2003; 3. Bernhardt et al, Laborwelt 5:18, 2004 (German)] ]