1. Making a Master or Working Cell Bank
Bioman 2009
July 27 to July 30
Rochester, NY
Presenter: Dana M. Hopkins
Wm. Davies, Jr. Career & Technical HS

2. Master Cell Bank (MCB) Established from a single clone
Represents a cell reserve “Frozen in Time”
--Preserves characteristics
--Prevents contamination and deterioration
Produced in accordance with regulatory standards (21CFR 610)

3. Cell line characterization
Testing objectives of cell line
--Confirm identity (expression construct)
--Confirm purity (contamination)
--Confirm genetic stability (coding region)
Quality assurance established from master bank to end-of-production/post production cells (EPC/PPC)

4. Safety testing of cell banks
Eliminates/minimize adventitious agents to the biopharmaceutical
--bacteria
--mycoplasma
--fungi
--viruses

5. Source of Contaminants
Cell Substrate
Endogenous viruses
Exogenous microbial contaminants
Source material screening
-Human (HIV, HBV, HCV, CJD, etc)
-Animal (TSE sources, species-specific viruses.

6. Contaminants (cont.) Raw Materials
*Cell culture reagents (animal and non- animal)
Environment
Water
Air
Human/Technicians

7. Regulatory Documents
CBER/FDA: Points to consider in cell line characterization
CBER/FDA: Points to consider in manufacturing and testing
European Pharmacopeia (EP)
US Pharmacopeia (USP)
Japanese Pharmacopeia (JP)

8. Validated In-house Guidelines
Species Identity: Confirmed by iso-enzyme analysis and cross-species contamination
Species Banding Pattern: Confirmed by agarose gel electrophoresis
DNA Fingerprinting: Karyology

9. Purity Testing Sterility:
--Bulk harvest/cell banks tested for bacterial & fungal contamination.
Mycoplasma:
--Two methods recommended by inoculation in broth and agar.

10. Purity Testing Adventitious viruses
--Invitro assay with indicator cell lines
--Invivo assay with embryonic chicken eggs
Retrovirus (rodent cell lines):
--XC plaque assay
--S+L- focus assay

11. Purity Testing Transmission Electron Microscopy (TEM)
Reverse transcriptase assay:
--Product enhanced RT (PERT)
--Unique enzyme in retroviruses
--PCR sensitive to cDNA enzyme

12. Building the Master Cell Bank Transformation or Transfection
Introduce Foreign Gene that expresses Protein Product: (bacterial transformation)
pick one pick one
  
Screen for expression of foreign gene
o o
oo o o
Bacteria
Lawn

13. Grow Cells to 90% Confluence
Images Courtesy of Corning Inc

14. Cell Preparation for Freezing
Check cell line for stability and contaminations.
Refeed cells to ensure log phase of growth.
Label cryotubes with cell line, cells/vial, date, MCB
Count cells with a hemocytometer. Use trypan blue for viability.

15. Freezing Media 60 ml DMEM, 40 ml FCS, 1 ml Penicillin-Streptomycin
Filter through 0.2u filter
Aliquot in 15ml conical tubes for long storage at -80, or refrigerator for shorter periods of time.
For 100% DMSO:
4ml pH adjusted medium (DMEM)
1ml sterile 100% DMSO
0.1ml versene (prevents clumping of cells)

16. Cell Prep. Cont. Transfer cell suspension to centrifuge tubes.
Centrifuge at 1000rpm fo 5 minutes, 2-8oC.
Siphon off all the medium.
Slowly add chilled freezing medium to yield 1 x 107 cells/ml.
Resuspend cells by gently pipetting.
Place tubes on ice. Dispense cells, 1 ml/vial.
Parafilm cryovials and place in -80 freezer.

17. Mammalian Cells Trypsinize adherent cells and pellet
For each 100 mm dish, resuspend pellet in half the volume of freezing medium. (if freezing 10 vials, add 5 mLs media)
20% DMSO made fresh daily
Add dropwise DMSO to 10% final vol.
Final suspension: DMEM with 20% FCS, 10% DMSO, cells from 100 mm dish.
Chill cells on ice in centrifuge tube before dispensing in pre-chilled, 1 mL vials

18. Thawing Mammal Cells Working Cell Bank
Points to Consider:
Cells should be thawed rapidly and then diluted slowly into warm growth medium.
Transfer one 1ml vial to 50ml centrifuge tube. Slowly (dropwise) add 10ml warm medium.
Pelleting DMSO cells may harm fragile cells.
DMSO is toxic to cells. Change media quickly.
DMSO is OSHA sensitive. Replace with glycerol if at all possible

19. Schrieber’s Protocol Thaw vial quickly in 370C water.
Transfer cells to sterile, 15ml centrifuge tube
Add FBS in 1 minute increments:
50ul/1min;100ul/1min; 200ul/1min; 400ul/1min; 800ul/1min
4) Centrifuge for 5 minutes at 1000rpm
5) Aspirate supernatant, resuspend in 5-6ml warm media.
7) Transfer to T-25 flask, incubate at 370C/5% CO2
8) After 24 hours, check viability, remove/add 5-6 ml fresh warm media.

20. References
Shama, B., “Manufacturing of Low Molecular Drugs”, Contocor, Raritan, NJ, 2005.
Blackwell, JV, “Mycoplasma-Recent developments in Detecting and Preventing Bioreactor Contaminants”, ISPE annual meeting, Scottsdale, AZ, Nov. 2005
Cooper, J., ECACC, “A cell banking process for the provision of cryo-preserved, “assay ready” cells for drug discovery programs. 16 July, 2009.
http: Cell line characterization.