| 摘要 |
Construction of a single gene encoding a signal-chain immunoglobulin-like molecule is described. This single-gene approach circumvents inefficiencies inherent in delivering two genes into a mammalian cell and in the assembly of a functional immunoglobul in molecule. It also facilitates ex vivo transfection of cells for gene-therapy protocols . The single-chain protein comprises the heavy- and light-chain variable (V H and V L) domains of a monoclonal antibody covalently joined through a short linker peptide, while the carboxy l end of a V domain is linked to the amino terminus of a human constant region such as .gamma. 1 Fc, through the hinge region. The single-chain protein assembles into a dimeric molecule of ~ 120 kDa and is secreted into the culture fluid. The single-chain immunoglobulin-like protein shows similar antigen binding affinity to that of chimeric or parental antibody an d mediates ADCC. This single-gene construct approach provides a way of generating an immunoglobulin- like molecule which retains the specificity, binding properties, and cytolytic activity of a parental monoclonal antibody, and thus is a useful therapeutic and diagnostic reagent against a range of antigens, such as human carcinomas. |
