Single-chain mono- and bispecific antibody derivatives with novel biological properties and antitumour activity from a COS cell transient expression system

Ther Immunol. 1994 Jan;1(1):3-15.


Single-chain antibody molecules were expressed from modified eukaryotic expression vectors as individual protein domains encoded on interchangeable cDNA cassettes. Two different single-chain antibody derivatives were constructed by linking individual light- and heavy-chain variable domains. The first was specific for the L6 tumour-associated antigen and the second was specific for human CD3. Each single-chain variable domain was genetically fused with an Fc 'tag' and expressed as a fusion protein in a COS cell transient transfection system. These single-chain antibody derivatives demonstrated specific binding to cells expressing appropriate antigen and bound with affinities similar to native antibody. The CD3 single chain molecule mediated stronger activation of PLC gamma 1 and similar levels of T-cell proliferation compared with native antibody. A bispecific Fv single-chain cassette was created by fusing the expression cassettes encoding the binding domains for L6 and CD3 single-chain molecules using oligonucleotide primers encoding a short 27-residue 'helical' peptide linker. The CD3-L6 variable domains were fused to the Fc tag and expressed in COS cells. The CD3-L6FvIg bispecific fusion protein mediated adhesion between T cells and L6-positive tumour cells, and stimulated potent T-cell proliferation and cytotoxicity against tumour cells expressing the L6 antigen.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibodies, Bispecific / genetics*
  • Antibodies, Monoclonal / genetics*
  • Antibodies, Monoclonal / immunology
  • Antibodies, Neoplasm / immunology*
  • Antibody Specificity
  • Antigens, Neoplasm / immunology
  • Base Sequence
  • CD3 Complex / immunology
  • Cell Adhesion
  • Chlorocebus aethiops
  • DNA Primers / chemistry
  • Genetic Vectors
  • Humans
  • Immunotoxins / genetics*
  • Lymphocyte Activation
  • Molecular Sequence Data
  • Recombinant Fusion Proteins / genetics*
  • T-Lymphocytes / immunology


  • Antibodies, Bispecific
  • Antibodies, Monoclonal
  • Antibodies, Neoplasm
  • Antigens, Neoplasm
  • CD3 Complex
  • DNA Primers
  • Immunotoxins
  • Recombinant Fusion Proteins