Engineering and characterization of a novel fusion protein incorporating B7.2 and an anti-ErbB-2 single-chain antibody fragment for the activation of Jurkat T cells.
The provision of the T-cell costimulatory molecule B7 to tumor cells can be an effective way to trigger a tumor-specific cytolytic T-cell response. One way to provide B7 to tumor cells would be to couple an antitumor antibody directly to B7. Such a molecule should target tumors displaying antigen and provide the costimulatory signal to T cells, resulting in the initiation of an antitumor T-cell response. To this end, a fusion protein was designed that incorporates a single-chain antibody fragment (scFv) to erbB-2 (Her2/neu), an oncogene product overexpressed by 30% to 50% of breast carcinomas, and the ECD of B7-2 (CD86). This fusion protein, expressed and purified from Pichia pastoris, was shown to retain binding activity to both counter receptors, erbB-2 and CD28. The fusion protein was also shown to target erbB-2-positive tumor cells and to deliver a CD28-specific T-cell costimulatory signal. These results suggest that a fusion protein engineered to target tumor cells and signal T cells for activation may be an effective means of cancer immunotherapy. Further studies should be performed to characterize the fusion protein in erbB-2 tumor-bearing mice for in vivo tumor targeting, biodistribution, and efficacy.
Marshall
K W
KW
Department of Anesthesia, University of California, San Francisco, USA.
Marks
J D
JD
D000595:Amino Acid Sequence; D000818:Animals; D015703:Antigens, CD / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D051940:B7-2 Antigen; D016466:CHO Cells; D006224:Cricetinae; D006801:Humans; D007135:Immunoglobulin Variable Region / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D019169:Jurkat Cells; D007700:Kinetics; D008213:Lymphocyte Activation / Q000235:genetics; D008562:Membrane Glycoproteins / Q000737:chemistry* / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D011485:Protein Binding / Q000235:genetics / Q000276:immunology; D015202:Protein Engineering / Q000379:methods; D011817:Rabbits; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000138:chemical synthesis* / Q000302:isolation & purification / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000276:immunology; D020349:Surface Plasmon Resonance; D014162:Transfection
D015703:Antigens, CD; D051940:B7-2 Antigen; D007135:Immunoglobulin Variable Region; D008562:Membrane Glycoproteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D011993:Recombinant Fusion Proteins; C497964:CD86 protein, human