Method for cell expansion

• US 9,845,455 B2
• Filed: 04/19/2013
• Issued: 12/19/2017
• Est. Priority Date: 05/15/2008
• Status: Active Grant

• Current Assignee: Cytiva Sweden AB (Danaher Corporation)
• Original Assignee: GE Healthcare Bio-Sciences AB (GE Healthcare Technologies, Inc.)
• Inventors: Anneren, Cecilia, Kaisermayer, Christian, Lundgren, Mats, Tschop, Johanna, Lundstrom, Therese, Magnusson, Ann-Christin, Blueml, Gerald
• Primary Examiner(s): Ault, Addison D
• Application Number:
  US13/866,169
• Publication Number:
  US 20130236970A1
• Time in Patent Office: 1,705 Days
• Field of Search: None
• CPC Class Codes: C12M 23/14 Bags
• CPC Class Codes: C12M 23/34 Internal compartments or partitions
• CPC Class Codes: C12M 25/16 Particles; Beads; Granular material; Encapsulation chemical or physical processes conducted in the presence of fluids and solid particles B01J8/00
• CPC Class Codes: C12M 47/02 Separating microorganisms from the culture medium; Concentration of biomass separating microorganisms from their culture media C12N1/02
• CPC Class Codes: C12N 5/0075 using microcarriers
• CPC Class Codes: C12N 5/0663 Bone marrow mesenchymal stem cells (BM-MSC)

Abstract

The present invention relates to a method for cell expansion. More closely, it relates to a method for expansion of cells, such as mesenchymal stem cells, on microcarriers in a plastic bag bioreactor. The invention enables expansion to therapeutic amounts of stem cells. The method comprises the following steps: a) addition of cells in cell culture medium and microcarriers to a plastic bag container; b) allowing the cells to adhere to the microcarriers while the container is kept substantially still; c) addition of further cell culture medium once the cells have adhered; d) culturing the cells under gentle and constant agitation; e) increase the surface area for continued culturing; and f) final harvesting of cells by an active detachment and separation step.

Claims

1. A method, comprising:

a) adding mesenchymal stem cells in a cell culture medium and microcarriers to a bag bioreactor wherein the volume of added mesenchymal stem cells and microcarriers is between 150-300 ml, the seeding density is 1-10 adherent cells/microcarrier and the amount of microcarriers is at least 0.2 g (dry weight) per liter;

b) allowing the mesenchymal stem cells to attach to the microcarriers while the bioreactor is kept in fixed position;

c) adding additional cell culture medium to the bioreactor once the mesenchymal stem cells are attached;

d) culturing the mesenchymal stem cells by agitation, to yield the cell culture; and

e) increasing the surface area for continued culturing, wherein the step of increasing includes;

i. securing the bag bioreactor in an angled upright position, at an opening in an upper corner of the bag bioreactor, by an external component such that the microcarriers are moved by gravity to a single corner inside the bag bioreactor opposite the upper corner;

ii. collecting the microcarriers by sedimentation in the single corner of the bag bioreactor, the microcarriers having the mesenchymal stem cells attached thereon;

iii. transferring the collected microcarriers to an external separation device using gravity flow or overpressure on the bag bioreactor

iv. detaching the mesenchymal stem cells from the microcarriers inside the external separation device;

v. separating the detached mesenchymal stem cells from the microcarriers by flowing, under agitation, a buffer through the external separation device;

vi. adding new microcarriers and the detached mesenchymal stem cells to the bag bioreactor for continued culturing;

f) harvesting the mesenchymal stem cells of step e) by active detachment and separation;

wherein step e) is repeated until 3-8 g microcarriers per liter medium is reached; and

wherein one therapeutic cell dose of mesenchymal stem cells can be produced per 2 liter of culture volume.

2. The method of claim 1, wherein the microcarriers are provided with magnetic particles.

3. The method of claim 1, wherein the mesenchymal stem cells are cells from adipose tissue, bone marrow or cord blood.

4. The method of claim 3, wherein the mesenchymal stem cells are adult mesenchymal stem cells.

5. The method of claim 1, wherein the mesenchymal stem cells are infected with a virus.

6. The method of claim 1, wherein the bag bioreactor is an inflated bioreactor bag.

7. The method of claim 1, wherein the mesenchymal stem cells are detached in step f, by using enzymes, thermo responsive agents, pH responsive agents, chelating agents and/or osmolality-changing agents.

8. The method of claim 7, wherein the mesenchymal stem cells detached in step f, by addition of a protease, such as trypsin.

9. The method of claim 1, wherein the external separation device comprises at least one screen with pores having circle-equivalent diameters larger than the average cell diameter and smaller than the average microcarrier diameter.

10. The method of claim 1, wherein the external separation device comprises a rotating agitator.

11. The method of claim 1, wherein the external separation device comprises a retentate compartment, separated from a permeate compartment by a screen sheet.

12. The method of claim 11, wherein the external separation device comprises a rotating agitator in the retentate compartment and the external separation device is positioned so that the retentate compartment is below the screen and the permeate compartment.

13. The method of claim 12, comprising a step of introducing the microcarriers in the retentate compartment under agitation, and adding a protease such as trypsin to the retentate compartment to allow the mesenchymal stem cells to detach from the microcarriers.

14. The method of claim 1, wherein the external separation device comprises one or more tubular screens.

15. The method of claim 14, wherein the external separation device comprises one or more tubular screens with the lumens fluidically connected to a retentate circuit and with a permeate compartment surrounding the one or more tubular screens.

16. The method of claim 14, wherein the external separation device comprises one or more tubular screens with the lumens fluidically connected to a permeate compartment and with a retentate compartment surrounding the one or more tubular screens.