An expression system for recombinant production of a desired protein comprises CHO cells transformed with a DNA sequence having the desired protein coding sequence under control of the human metallothionein-II promoter. The cells can be maintained on serum-free medium and induced in the presence of an induction mediator. In addition, the system may include an enhancer element and/or a resistance-conferring gene to provide increased levels of expression. The system can process genomic as well as intronless DNA, and is capable of producing proteins which have the same characteristics as those obtained from native sources. Human growth hormone which is indistinguishable from that produced by the pituitary has been thus produced.
This application is a continuation of U.S. Ser. No. 06/801,674, filed 25 Nov. 1985 and now abandoned, which is a continuation-in-part of U.S. Ser. No. 06/701,296, filed 13 Feb. 1985 and now abandoned.
The invention relates to an expression system which permits control of the levels of protein produced, and optionally provides production of the mature form of the protein directly. The expression systems of the invention include the desired gene downstream of a first DNA which comprises the reverse transcript of an inducible translational regulator and a second DNA which is the reverse transcript of an mRNA capable of self-stabilization. This translated sequence is in turn under the control of a transcriptional promoter which may also be inducible. In a preferred embodiment, the inducible translational regulator is the iron responsive element (IRE) region of ferritin mRNA, and the stabilizing element is also a portion of the ferritin sequence. The expression system is useful, especially, for the production of toxic proteins since protein production can be delayed until desired.
The invention relates to a CHO cell-line capable of producing antibody, the cell-line having been co-transfected with a vector capable of expressing the light chain of the antibody and a vector capable of expressing the heavy chain of the antibody wherein the vectors contain independently selectable markers; also included is a CHO cell-line capable of producing a human antibody or an altered antibody, the cell-line having been transfected with a vector capable of expressing the light chain of the antibody and the heavy chain of the antibody; process for the production of antibody using a CHO cell-line and antibody having CHO glycosylation.
Methods of production of desired recombinant proteins, polypeptides and peptides are disclosed which utilize mammalian host cells engineered for autonomous and regulated growth in low cost protein/serum-free culture media. Preferred host cells express insulin or an insulin-like growth factor, and/or transferrin and are engineered so that addition of an inducer (e.g., ZnCl.sub.2 +CdCl.sub.2) halts growth and simultaneously induces the expression of the desired recombinant protein, polypeptide or peptide.
The invention relates to a CHO cell-line capable of producing antibody, the cell-line having been co-transfected with a vector capable of expressing the light chain of the antibody and a vector capable of expressing the heavy chain of the antibody wherein the vectors contain independently selectable markers; also included is a CHO cell-line capable of producing a human antibody or an altered antibody, the cell-line having been transfected with a vector capable of expressing the light chain of the antibody and the heavy chain of the antibody; process for the production of antibody using a CHO cell-line and antibody having CHO glycosylation.
The invention relates to a CHO cell-line capable of producing antibody, the cell-line having been co-transfected with a vector capable of expressing the light chain of the antibody and a vector capable of expressing the heavy chain of the antibody wherein the vectors contain independently selectable markers; also included is a CHO cell-line capable of producing a human antibody or an altered antibody, the cell-line having been transfected with a vector capable of expressing the light chain of the antibody and the heavy chain of the antibody; process for the production of antibody using a CHO cell-line and antibody having CHO glycosylation.
