Temperature shift for high yield expression of polypeptides in yeast and other transformed cells
Methods for producing heterologous proteins are disclosed. In particular, the present disclosure provides improved methods of producing desired proteins, including multi-subunit proteins such as antibodies, with a higher yield and improved purity. In exemplary embodiments, the transformed cells are a yeast, e.g., methylotrophic yeast such as Pichia pastoris.
1. A method of producing a desired antibody in yeast cells, comprising:
(a) culturing at a first temperature yeast cells comprising one or more genes that encode said desired antibody; and
(b) culturing said yeast cells at a second temperature and allowing said yeast cells to produce said desired antibody;
wherein said first temperature is between 27.5 degrees C. and 28.5 degrees C. and said second temperature is between 30 degrees C. and 31 degrees C., and
wherein the promoter or promoters which regulate the transcription of the one or more genes that encode said desired antibody are not temperature inducible.
2. The method of claim 1 , wherein said yeast cells are Pichia yeast cells.
3. The method of claim 1 , wherein said yeast cells are Pichia pastoris yeast cells.
4. The method of claim 1 , wherein said first temperature is 28 degrees C.
5. The method of claim 1 , wherein said antibody comprises a human antibody or humanized antibody.
6. The method of claim 1 , wherein said method increases the yield of said desired antibody relative to the same method effected without a difference between said first temperature and said second temperature.
7. The method of claim 1 , wherein said method decreases the relative abundance of one or more product-associated variants relative to the same method effected without a difference between said first temperature and said second temperature.
8. The method of claim 1 , wherein said method decreases the relative abundance of product-associated variants having a higher or lower apparent molecular weight than said antibody as detected by size exclusion chromatography or gel electrophoresis relative to the same method effected without a difference between said first temperature and said second temperature.
9. The method of claim 1 , wherein said method decreases the relative abundance of antibodies having aberrant disulfide bonds relative to the same method effected without a difference between said first temperature and said second temperature.
10. The method of claim 1 , wherein said method decreases the relative abundance of antibodies having reduced cysteines relative to the same method effected without a difference between said first temperature and said second temperature.
11. The method of claim 1 , wherein said method decreases the relative abundance of antibodies having aberrant glycosylation relative to the same method effected without a difference between said first temperature and said second temperature.
12. The method of claim 1 , wherein said yeast cells comprise methylotrophic yeast.
13. The method of claim 12 , wherein the genes that encode said desired antibody are integrated into one or more genomic loci.
14. The method of claim 1 , wherein at least one of the genes encoding said subunits of said desired antibody are expressed under control of an inducible promoter.
15. The method of claim 1 , wherein step (a) comprises culturing said yeast cells in a culture medium comprising glycerol as a carbon source until said glycerol is exhausted.
16. The method of claim 1 , wherein said desired antibody is expressed under control of a promoter selected from the group consisting of: the CUP1, AOX1, ICL1, glyceraldehyde-3-phosphate dehydrogenase (GAP), FLD1, ADH1, alcohol dehydrogenase II, GAL4, PHO3, PHO5, and Pyk promoters, tetracycline inducible promoters, thiamine inducible promoters, chimeric promoters derived therefrom, yeast promoters, mammalian promoters, insect promoters, plant promoters, reptile promoters, amphibian promoters, viral promoters, and avian promoters.
17. The method of claim 1 , wherein said yeast cells comprise diploid, tetraploid cell, or polyploid cells.
18. The method of claim 1 , further comprising purifying said desired antibody from said yeast cells or from the culture medium.
19. The method of claim 18 , wherein said desired antibody is purified from an intracellular component, cytoplasm, nucleoplasm, or a membrane of said yeast cells.
20. The method of claim 1 , wherein said yeast cells secrete said desired antibody into the culture medium.
21. The method of claim 1 , wherein step (a) comprises a batch phase comprising culturing the yeast cell in a medium comprising a carbon source.
22. The method of claim 1 , wherein step (b) comprises a fed batch phase.
23. The method of claim 4 , wherein said yeast cells comprise yeast of the genus Pichia.
24. The method of claim 4 , wherein said yeast cells comprise Pichia pastoris.
25. The method of claim 1 , wherein said yeast cells comprise Pichia angusta, Pichia guilliermondii, Pichia methanolica , or Pichia inositovera.
26. The method of claim 1 , wherein at least one of the genes encoding said subunits of said desired antibody are expressed under control of a promoter selected from the group consisting of the AOX1 promoter, the CUP1 promoter, a tetracycline inducible promoter, a thiamine inducible promoter, and the FLD1 promoter.
27. The method of claim 13 , wherein the genes that encode said desired antibody are integrated into one or more genomic loci selected from the group consisting of the pGAP locus, 3′ AOX TT locus; PpURA5; OCH1; AOX1; HIS4; GAP; pGAP; 3′ AOX TT; ARG; and the HIS4 TT locus.