Xiangbin Wang

A novel bivalent single‐chain variable fragment (scFV) inhibits the action of tumour necrosis factor α

Suppression of TNFα (tumour necrosis factor α) activity is widely considered to be among the most efficient treatments available for chronic inflammatory diseases. Here, a bivalent scFv (single‐chain variable fragment) fragment, named TNF‐BAb, was engineered by fusing two anti‐TNFα scFV fragments in tandem via a long and flexible linking peptide derived from human serum albumin and produced in functional form from Escherichia coli inclusion bodies. The bioactivity assays demonstrated that TNF‐BAb gained enormously in avidity and showed a much stronger ability to inhibit the biological action of TNFα, indicating that TNF‐BAb may become a good candidate for anti‐TNFα therapy.

Fusion of chemotactic peptide to a single-chain bi-specific antibody (scBsAb) potentiates its cytotoxicity to target tumour cells

Anti‐tumour BsAb (bi‐specific antibody) has been proved very effective in killing tumour cells both in vitro and in vivo. In order to enhance its ability to recruit and activate T‐lymphocytes and then improve tumour‐specific cytolysis, an anti‐ovarian carcinoma/CD3 BsAb, BHL‐I, was fused to N‐terminal 18 peptide of CCL21 (CC chemokine ligand 21) to produce a new chemotactic BsAb, named 18TBHL. It was expressed in soluble form in the cytoplasm of Escherichia coli and purified with DEAE anion‐exchange chromatography and immobilized‐metal‐ion affinity chromatography. The chemotactic ability of 18TBHL to PBLs (peripheral‐blood lymphocytes) was detected by Boyden chamber chemotaxis assay. The specific ability to bind to ovarian carcinoma cells, SKOV3, and PBLs was tested by ELISA and flow cytometry. Just as expected, the enhanced tumour‐specific cytolysis of 18TBHL was validated by MTT [3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyl‐2H‐tetrazolium bromide] method and flow cytometry. The results indicated that fusion of chemotactic peptide to BsAb potentiated its cytotoxicity to tumour cells in vitro. It suggests that 18TBHL may be a promising candidate agent in cancer immunotherapy.