Specific active immunotherapy with the HEBERSaVax VEGF-based cancer vaccine: From bench to bedside.

HEBERSaVax is a cancer therapeutic vaccine candidate based on the combination of a recombinant antigen representative of human vascular endothelial growth factor (VEGF), and clinically tested adjuvants. The vaccine has been shown to inhibit tumor growth and metastases in mice, and to induce VEGF-blocking antibodies and specific T-cell responses in several animal species, all with an excellent safety profile. After preclinical studies, two sequential phase 1 clinical trials were conducted with HEBERSaVax to assess safety, tolerance, and immunogenicity in patients with advanced solid tumors, at different antigen doses, and combined with two distinct adjuvants.

Vaccination with a mutated variant of human Vascular Endothelial Growth Factor (VEGF) blocks VEGF-induced retinal neovascularization in a rabbit experimental model.

Vascular Endothelial Growth Factor (VEGF) is a key driver of the neovascularization and vascular permeability that leads to the loss of visual acuity of eye diseases like wet age-related macular degeneration, diabetic macular edema, and retinopathy of premature. Among the several anti-VEGF therapies under investigation for the treatment of neovascular eye diseases, our group has developed the vaccine candidate CIGB-247-V that uses a mutated form of human VEGF as antigen. In this work we evaluated if the vaccine could prevent or attenuate VEGF-induced retinal neovascularization in the course of a rabbit eye neovascularization model, based on direct intravitreal injection of human VEGF.

Affinity maturation and fine functional mapping of an antibody fragment against a novel neutralizing epitope on human vascular endothelial growth factor.

We have previously reported the isolation of a novel single-chain variable fragment (scFv) against vascular endothelial growth factor (VEGF), from a phage-displayed human antibody repertoire. This scFv, denominated 2H1, was shown to block the binding of VEGF to its receptor but exhibited a moderate binding affinity. Here, we describe the affinity maturation of the 2H1 scFv.

Comparative in vitro and experimental in vivo studies of the anti-epidermal growth factor receptor antibody nimotuzumab and its aglycosylated form produced in transgenic tobacco plants.

A broad variety of foreign genes can be expressed in transgenic plants, which offer the opportunity for large-scale production of pharmaceutical proteins, such as therapeutic antibodies. Nimotuzumab is a humanized anti-epidermal growth factor receptor (EGFR) recombinant IgG1 antibody approved in different countries for the treatment of head and neck squamous cell carcinoma, paediatric and adult glioma, and nasopharyngeal and oesophageal cancers. Because the antitumour mechanism of nimotuzumab is mainly attributed to its ability to interrupt the signal transduction cascade triggered by EGF/EGFR interaction, we have hypothesized that an aglycosylated form of this antibody, produced by mutating the N(297) position in the IgG(1) Fc region gene, would have similar biochemical and biological properties as the mammalian-cell-produced glycosylated counterpart.

Production of plantibodies in Nicotiana plants.

Because of the wide use and high demand in medicine, monoclonal antibodies are among the main recombinant pharmaceuticals at present, although present limitations of the productive platforms for monoclonal antibodies are driving the improvement of the large-scale technologies and the development of alternative expression systems. This has drawn the attention on plants as expression system for monoclonal antibodies and related derivatives, owning the capacity of plants to properly express and process eukaryotic proteins with biological activity resembling that of the natural proteins. In this chapter, the procedures from the isolation of the monoclonal antibody genes to the biochemical and biological characterization of the plant-expressed monoclonal antibody are described.

Fighting cancer with plant-expressed pharmaceuticals.

Cancer is one of the most prevalent diseases worldwide, which explains why biological therapies for cancer are forecast to make up 35% of total recombinant pharmaceuticals by 2010. Because of the high demand for cancer drugs, the need to lower production costs and the constraints of present production technologies for recombinant pharmaceuticals (such as the difficulties involved in culturing bacteria, yeast and mammalian cells), attention has recently been focused on recombinant expression of pharmaceutical anti-cancer proteins in plants. This review aims to provide an update on the most recent publications about anti-cancer recombinant pharmaceuticals expressed in plants, as well as on the relevant technical issues, potential and prospects of this emerging production system.

Double acylation for identification of amino-terminal peptides of proteins isolated by polyacrylamide gel electrophoresis.

We report here a method for the identification of free or blocked N-terminal peptide of in-gel digested isolated proteins. The primary amino groups of the gel-entrapped protein are blocked with normal acetic or succinic anhydride, and the protein is digested with a high-specificity protease. The generated peptides are treated with an equimolar mixture of normal and deuterated acetic anhydride.

A multivalent recombinant antibody fragment specific for carcinoembryonic antigen.

In the present paper we report the development of a bivalent scFv (single-chain Fv) antibody fragment, starting from a mouse mAb (monoclonal antibody) specific for CEA (carcinoembryonic antigen) that has received approval for in vivo radioimmunodiagnosis in humans. The diabody is well expressed in Escherichia coli, is easily purified by a combination of immobilized metal ion affinity chromatography and gel filtration and exhibits high affinity and specificity for CEA, comparable with those of the original mAb. Biodistribution experiments in athymic nude mice transplanted with human CEA+ cancer cells showed that the 125I-labelled diabody preferentially localizes in the tumour tissue and that retention is still high 48 h after injection.

Transient expression in tobacco leaves of an aglycosylated recombinant antibody against the epidermal growth factor receptor.

When generating stably transformed transgenic plants, transient gene expression experiments are especially useful to rapidly confirm that the foreign molecule of interest is correctly assembled and retains its biological activity. TheraCIM(R) (CIMAB S.A.