Cost effective filamentous phage based immunization nanoparticles displaying a full-length hepatitis B virus surface antigen

Hepatitis B virus (HBV) is one of the major causes of chronic hepatitis, cirrhosis and liver cancer. In combating HBV infections, HBV diagnosis and vaccination are therefore critical. The hepatitis B virus surface antigen (HBsAg) is a key target molecule in developing vaccines and diagnostic systems. To date, although HBsAg has been expressed in bacteria, yeasts and mammalian cells, there are still limitations in the existing ones, which leave the necessity for searching new HBsAg production methods. In this study, a simple phage display-based method was developed to produce the purified full-length HBsAg molecules for further immunization studies. For this purpose, the HBsAg coding gene was cloned into a pCANTAB5E phagemid vector and expressed on the surface of M13 filamentous phages. The HBsAg-expressing phage nanosystem was then used as immunization agent in BALB/cJ mice. The ELISA results for sera obtained from mice immunized with HBsAg-displaying phage particles revealed an immune response against HBsAg. These results demonstrate the potential use of a full-length antigen to be displayed on phages as cost effective adjuvant-free immunization agents as an alternative to the highly purified and more expensive antigens conjugated with carrier molecules

Cloning of anti-hbsag single chain variable fragments from hybridoma cells for one-step elisa

Hepatitis B virus (HBV) infection is a worldwide health problem. More than 400 million people are chronic HBV carriers in the world. Infected individuals are at a high risk of developing liver cirrhosis and hepatocellular carcinoma as the main consequences of HBV. The discoveries of fast diagnostic systems and new therapeutic applications are crucial in the fight against viral hepatitis. In this paper we present the generation of a single-chain variable fragment (scFv) from a mouse monoclonal antibody specific to the HBV surface antigen (HBsAg) and demonstrate its expression as a bacterial alkaline phosphatase (AP) fusion protein. In this study, we constructed scFvs from hybridoma cells expressing HBsAg-specific antibody using phage display technology and expressed them in Escherichia coli. The anti-HBsAg scFvs were inserted into pQE-2 vector to produce scFv antibody genetically fused to bacterial AP. Reproducibility of the recombinant HBsAg-scFv fusion protein was tested using Enzyme-linked Immunosorbent Assay (ELISA). Present preliminary findings indicate that the anti-HBsAg-scFv AP conjugate could be further used for the development of one-step ELISA for the detection of HBV

Novel short peptides isolated from phage display library inhibit vascular endothelial growth factor activity.

Signal transduction through the vascular endothelial growth factor (VEGF)-VEGF receptor (VEGFR) pathway has a pivotal importance in angiogenesis, and has therefore become a prime target in antitumor therapy. In search for peptides antagonizing VEGF binding to its receptors, we screened a random heptamer library displayed on phage for peptides that bind the whole VEGF165 molecule and inhibit VEGF dependent human umbilical vein endothelial cell (HUVEC) proliferation. Two selected peptides with sequences WHLPFKC and WHKPFRF were synthesized. Biacore and matrix-assisted laser desorption/ionization timeof- flight mass spectrometry analysis indicated that these peptides bind the VEGF homodimer in a concentration- dependent manner, with micromolar affinity, and with a 2:1 peptide:VEGF stoichiometry. They inhibited HUVEC proliferation in vitro by 77 and 55%, respectively. Taken together, our results indicate that these peptides could be potent inhibitors of angiogenesis. Furthermore, we show that the peptide- VEGF binding properties can be quantified, a prerequisite for the further optimization of binders

Generation of new protective HBV vaccine using the phage display method

European Biotechnology Congress -- SEP 28-OCT 01, 2011 -- Istanbul, TURKEYWOS: 000295310800102…European Biotechnol Themat Network Asso

Novel short peptides isolated from phage display library inhibit vascular endothelial growth factor activity.

Signal transduction through the vascular endothelial growth factor (VEGF)-VEGF receptor (VEGFR) pathway has a pivotal importance in angiogenesis, and has therefore become a prime target in antitumor therapy. In search for peptides antagonizing VEGF binding to its receptors, we screened a random heptamer library displayed on phage for peptides that bind the whole VEGF165 molecule and inhibit VEGF dependent human umbilical vein endothelial cell (HUVEC) proliferation. Two selected peptides with sequences WHLPFKC and WHKPFRF were synthesized. Biacore and matrix-assisted laser desorption/ionization timeof- flight mass spectrometry analysis indicated that these peptides bind the VEGF homodimer in a concentration- dependent manner, with micromolar affinity, and with a 2:1 peptide:VEGF stoichiometry. They inhibited HUVEC proliferation in vitro by 77 and 55%, respectively. Taken together, our results indicate that these peptides could be potent inhibitors of angiogenesis. Furthermore, we show that the peptide- VEGF binding properties can be quantified, a prerequisite for the further optimization of binders