BACKGROUND: A diabody is a bispecific antibody that is capable of recruiting a polyclonal T cell to antibody target-expressing tumor cells. However, the two chains of diabodies tend to dissociate because they are integrated non-covalently. Therefore, it is necessary to remodel the diabody to increase its stability in order to enhance the antitumor activity. METHODS: We constructed an antiCD3×antiCD19 diabody with one binding site for the T cell antigen receptor (TCRCD3) and the other for the B cell-specific antigen (CD19) by recombinant gene engineering technology. Cysteine residues were introduced into the V domains of the anti-CD3 segment. The stability and cytotoxicity of the two diabodies were compared in vitro and vivo. RESULTS: The disulfide-stabilized (ds) diabodies produced by Escherichia coli were secreted with high yields in a fully active form without a decrease in affinity. Compared with the parental diabody, the disulfide-stabilized (ds) diabody proved more stable in vitro and in vivo without reducing binding affinity. Both were able to effectively eliminate human lymphoma Raji cells by redirecting T lymphocytes in vitro and in vivo, but the ds diabody was more effective in inhibiting the growth of xenografts transplanted in BALB/C nude mice. CONCLUSION: The antiCD3×antiCD19 ds diabody is more suitable for a controlled polyclonal T cell therapy of human CD19-positive B cell malignancies than its parental diabody.
BACKGROUND: A diabody is a bispecific antibody that is capable of recruiting a polyclonal T cell to antibody target-expressing tumor cells. However, the two chains of diabodies tend to dissociate because they are integrated non-covalently. Therefore, it is necessary to remodel the diabody to increase its stability in order to enhance the antitumor activity. METHODS: We constructed an antiCD3×antiCD19 diabody with one binding site for the T cell antigen receptor (TCRCD3) and the other for the B cell-specific antigen (CD19) by recombinant gene engineering technology. Cysteine residues were introduced into the V domains of the anti-CD3 segment. The stability and cytotoxicity of the two diabodies were compared in vitro and vivo. RESULTS: The disulfide-stabilized (ds) diabodies produced by Escherichia coli were secreted with high yields in a fully active form without a decrease in affinity. Compared with the parental diabody, the disulfide-stabilized (ds) diabody proved more stable in vitro and in vivo without reducing binding affinity. Both were able to effectively eliminate humanlymphoma Raji cells by redirecting T lymphocytes in vitro and in vivo, but the ds diabody was more effective in inhibiting the growth of xenografts transplanted in BALB/C nude mice. CONCLUSION: The antiCD3×antiCD19 ds diabody is more suitable for a controlled polyclonal T cell therapy of humanCD19-positive B cell malignancies than its parental diabody.
Authors: A Löffler; P Kufer; R Lutterbüse; F Zettl; P T Daniel; J M Schwenkenbecher; G Riethmüller; B Dörken; R C Bargou Journal: Blood Date: 2000-03-15 Impact factor: 22.113