Production of genetically engineered antibodies in myeloma cells: Design, expression, and applications

The criteria for producing recombinant antibodies in myeloma cells are discussed. Heavy- and light-chain genes are cloned into expression vectors with different selectable markers and transfected simultaneously into recipient cells. Expression vectors that contain not only the elements required for gene expression but features that facilitate the exchange of variable or constant region genes have been designed. Obtaining variable region genes of interest has been greatly facilitated by the advent of the polymerase chain reaction. Murine variable region genes may be joined to human constant regions, whose domain structure has been exploited by the design of cloning "cassettes." In these, unique restriction sites placed between constant region exons allow for domain duplication, deletion, or exchange. Immunoglobulin fusion proteins, in which antigen specificities have been fused to heterologous proteins, have been produced successfully. Certain antibody properties have also been altered by site-directed mutagenesis. These manipulations not only have provided useful insights into structure-function relationships in antibodies, but enable the production of antibodies with altered or novel properties.