[Expression of "chimeric" (murine/human) immunoglobulin genes in lymphoid and nonlymphoid cells]

A recombinant tandem of mouse/human immunoglobulin (Ig) genes was constructed and inserted in the plasmid pGEM1 under the control of the T7 RNA polymerase promoter. Constant Ig genes of murine origin were replaced with human genomic ones. Isotype IgG1 was changed for IgE. Lymphoid cell line Sp2/0 and CHO (chinese hamster ovary) cells were used for transfection. Both cell lines contained the semisynthetic gene of T7 RNA polymerase in their genomes and stably expressed this polymerase. Transfected clones of Sp2/0 and CHO cells synthesized k-light (25 kD) and epsilon-heavy (70 kD) chains of Ig and the corresponding mRNAs. Both lymphoid and nonlymphoid transfected cell lines synthesized functionally active antibodies interacting with the antigen (pig transferrin). Particular clones synthesized up to 150 ng/ml of chimeric antibodies. However, only lymphoid Sp2/0 cells were capable of efficient secretion. Nonlymphoid CHO cells were able to produce antibodies, but incapable of their efficient secretion.