Titerless Infected-cells Preservation and Scale-up (TIPS) David J. Wasilko & S. Edward Lee Pfizer Global Research & Development Groton, CT

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1 Titerless Infected-cells Preservation and Scale-up (TIPS) David J. Wasilko & S. Edward Lee Pfizer Global Research & Development Groton, CT 1

2 TIPS Advantages 1. Titerless system 2. Stable baculovirus stocks 3. Rapid, streamlined process 4. Readily scaleable 2

3 Using the standard method (9-10 weeks to 100-L scale) Using TIPS (2-3 weeks to 100-L scale) 3

4 Presentation Overview Compare typical baculovirus stock to the TIPS stock Baculovirus stock preparation Protein expression using TIPS Long term stability of the TIPS baculovirus stock Process scale-up From a 1-mL baculovirus stock to 10-L or 100-L in one easy step Scale-up in 7-L (5-L liquid) bioreactor 4

5 Baculovirus Stock: Standard Method Start over from bacmid stage Time (months/years) Drop in titer Degradation: Proteases Nucleases Titered Virus Stock (4 C) (Passage 1, 2, 3 ) - Titer - Evaluate Expression - Amplify Re-titer Before Use / Amplification 5

6 TIPS Stock: Baculovirus Infected Insect Cells (BIIC) Baculovirus stored and cryo-preserved within the cell. Time (months/years) Virus titer is not needed with TIPS! Infected Sf9 cell ( -80 C) Thaw the infected Sf9 cells No Stability Issues Small Volume 6

7 The Key to the TIPS Process: Baculovirus-Infected Insect Cell (BIIC) Stocks. Infect Sf9 cells with baculovirus Estimate the MOI (emoi 3.0) In general, infected cells produce ~100 pfu/cell Allow the cells to become infected Monitor diameter increase (~2-3 µm) High cell viability (>90% preferred) Cryo-preserve the healthy infected cells 7

8 TIPS Process and Cell Diameter One of the most important parameter in the TIPS process is cell diameter. Monitor the infection process in real time Used to prepare the BIIC stock Used to predict protein expression Cell Counters: Cedex (Innovatis) Vi-CELL (Beckman Coulter) Cellometer Auto T4 (Nexcelom Bioscience) 8

9 Virus Stock Comparison Volume Environment Storage Temp. Stability Titering Standard Virus Stocks >100 ml Spent media 4-8 o C Questionable Necessary TIPS Infected Cell Stocks 1 ml Native host cells -80 o C No issues Eliminated 9

10 Evaluation of Baculovirus Storage in Sf9 Insect Cells Model protein to evaluate baculovirus storage in the cell Secreted, his-tagged Infected an Sf9 culture with baculovirus (MOI = 3) Monitored cell growth parameters Prepared BIICs every 6 hours 10

11 Cell Growth and Viability During the Infection Process Viable Cell Density ml x x x x10 6 V iable C ell D ensity (m L -1 ) V iability (% ) Viability (% ) x x Time (Hours post infection) 50 11

12 Cell Diameter Increased During the Infection Process Average Cell Diameter (um) 19.0 Average Cell Diameter (um) Time (Hours post infection) 12

13 Change in Cell Diameter is an Indicator of Virus Infection/Release Average Cell Diameter (um) 19 Average Cell Diameter (um) Baculovirus Titer (PFU/mL) Baculovirus Titer (PFU/m L) 1x x10 8 1x x Time (Hours post infection) 13

14 Change in Cell Diameter is an Indicator of Virus Infection/Release Average Cell Diameter (um) 19 Cell Viability (% ) Average Cell Diameter (um) Baculovirus Titer (PFU/mL) Baculovirus Titer (PFU/m L) 1x x10 8 1x Viability (%) x Time (Hours post infection) 14

15 Baculovirus Survival in the Cryopreserved Infected Cells Will the infection process continue after freezing and thawing the BIIC? 1. Thaw the 6-hpi and 12-hpi BIIC stocks 2. Transfer the cells to fresh medium 3. Recovery cell density similar to the original culture at the time of cryopreservation 4. Monitor the infection process by changes in cell diameter 15

16 Comparison of the Original Infection to the 6-Hour BIIC Stock 20 Exp No. 1: Cell Diameter (um) Exp No. 2: Cell Diameter (um) (6-Hour BIIC) Average Cell Diameter (um) Time (Hours post infection) 16

17 Comparison of the Original Infection to the 12-Hour BIIC Stock 20 Exp No. 1: Cell Diameter (um) Exp No. 2: Cell Diameter (um) (12-Hour BIIC) Average Cell Diameter (um) Time (Hours post infection) 17

18 Can the infected cells be used for protein expression? 1-mL 24-hpi BIIC Vial 10 7 Cells/mL (10 9 PFU/mL) Dilution Flask 100-mL 1-mL 1-mL 1-mL (1:100) 100-mL/Flask (1:100) 1-BIIC Vial/10-L Flask 1 Flask 2 Flask 3 Initial Cell Densities: 0.50 x 10 6 Sf9 cells/ml (emoi ~ 0.10) 0.75 x 10 6 Sf9 cells/ml (emoi ~ 0.07) 1.00 x 10 6 Sf9 cells/ml (emoi ~ 0.05) Total Dilution (10-4 ) * Initial cell densities kept low to minimize nutrient limitation effects. * 18

19 Infection Kinetics were Similar in all Three Cultures Viable Cell Density ml SF1 Via. Cell Density (#/ml) SF2 Via. Cell Density (#/ml) SF3 Via. Cell Density (#/ml) Time (hpi) 19

20 Similar Drop in Cell Viability Cell Viability (%) SF1 Viability (% ) SF2 Viability (% ) SF3 Viability (% ) Time (hpi) 20

21 Cell Diameter Indicated that the Cultures were Equally Infected Average Cell Diameter (um) SF1 Diameter (um) SF2 Diameter (um) SF3 Diameter (um) Time (hpi) 21

22 Expression Profile of the Secreted, His-tagged Protein in Flasks 1 and 2 (Western blot) Flask 1 Flask 2 (Hours post infection) M FB/C M FB/C: Optimized control sample from a standard infection. 5.0 x10e5 cells/ml 7.5 x 10e5 cells/ml (Cell density when infected) 22

23 Expression Profile of the Secreted, His-tagged Protein in Flasks 3 (Western blot) Flask 3 (Hours post infection) FB/C M FB/C: Optimized control sample from a standard infection. 1.0 x10e6 cells/ml (Cell density when infected) 23

24 How Stable is the BIIC Stock? New, larger BIIC stock prepared (18-vials) Evaluate BIIC stability: Periodically thaw one BIIC vial. Infect Sf9 cells and conduct a time course study in shake flasks. Evaluate protein expression by Western blot. 24

25 BIIC Stability Determined by Protein Expression (Western blot) Months of Storage Time (hpi): M M The BIIC stock was stable for at least 37 months. 25

26 Stability Study: The BIIC stock has been stable for at least 60 months. 0 Months (2001) 49 Months (2005) 60 Months (2006) Infection Time (hpi) M M M x10e5 cells/ml 7.5x10e5 cells/ml 7.9x10e5 cells/ml (Cell density when infected) 26

27 How can the infected cells be used for scale-up? TIPS Direct Scale-up From 1 ml to 10-L 1-mL BIIC Vial 10 7 Cells/mL (10 9 PFU/mL) 100-mL (1:100) TIPS Direct Scale-up From 1 ml to 100-L 1-mL 1-mL (1:100) 100-mL 1-mL (1:10) (1:100) 10-mL 100-mL (1:1,000) Cells emoi ~ 0.1 Cells 100-mL (10-4 ) 100-mL (10-5 ) emoi ~ 0.01 Test Expression Evaluate Cell 10-L lines Cell Scale-up densities Culture (10-4 ) media Test Expression Evaluate Cell lines 100-L Cell Scale-up densities Culture (10 media -5 ) 27

28 How can the infected cells be used for scale-up? TIPS Direct Scale-up From 1 ml to 10-L 1-mL (1:100) Cells 100-mL (10-4 ) Test Expression 1-mL BIIC Vial 10 7 Cells/mL (10 9 PFU/mL) 100-mL (1:100) TIPS Direct Scale-up From 1 ml to 100-L 100-mL 1-mL 1-mL (1:10) (1:100) 10-mL 100-mL (1:1,000) emoi ~ 0.1 Cells 100-mL (10-5 ) emoi ~ L Scale-up (10-4 ) Test Expression 100-L Scale-up (10-5 ) 28

29 Bioreactor Scale-up Using the 60 Month BIIC Stock Scale-up in 7-L Bioreactors (5-L Liquid) 1-BIIC/10-L Volume Ratio Cells infected at approx. 8.5x10e5 cells/ml 1-BIIC/100-L Volume Ratio Additional round of baculovirus amplification Cells infected at approx. 5.5x10e5 cells/ml Evaluate protein expression by Western blot. 29

30 Scale-up in 7-L Bioreactors (5-L Liquid) TIPS Scale-up 1-BIIC/10-L Ratio 1-mL BIIC Vial 10 7 Cells/mL (10 9 PFU/mL) 100-mL TIPS Scale-up 1-BIIC/100-L Ratio 1.5-mL (1:100) 50-mL (1:100) Cells 150-mL (10-4 ) (1:100) 10-mL 100-mL (10-3 ) (1:10) 50-mL (1:100) Shaker Flask (10-4 ) emoi ~ 0.1 Bioreactor A 5-L Scale-up (1-BIIC/10-L) (10-4 ) Bioreactor B 5-L Scale-up (1-BIIC/100-L) (10-5 ) emoi ~

31 Bioreactor Culture (1-BIIC/10-L Ratio) (Cell Growth and Viability During the Infection Process) Viable Cell Density ml x x10 6 Bioreactor A (Cell Density) Bioreactor A (Viability) Viability (%) x Time (Hours post infection) 0 31

32 Bioreactor Culture vs. Shake Flask Culture (1-BIIC/10-L Ratio) (Cell Growth and Viability During the Infection Process) Viable Cell Density ml x x10 6 Bioreactor A (Cell Density) Bioreactor A (Viability) Shake Flask Culture (Cell Density) Shake Flask Culture (Viability) Viability (%) x Time (Hours post infection) 0 32

33 Bioreactor Culture (1-BIIC/10-L Ratio) (Change in Cell Diameter During the Infection Process) Cell Diameter (um) 19.0 Bioreactor A Time (Hours post infection) 33

34 Bioreactor Culture vs. Shake Flask Culture (1-BIIC/10-L Ratio) (Change in Cell Diameter During the Infection Process) Cell Diameter (um) 19.0 Bioreactor A Shake Flask Incubator temperature ~ 2 C above the set point! Time (Hours post infection) 34

35 Protein Expression: 1-BIIC/10-L Volume Ratio in a Flask and a 7-L (5-L Liquid) Bioreactor Shake Flask (2006) Bioreactor A (2006) Infection Time (hpi) M M 7.9x10e5 cells/ml 8.6x10e5 cells/ml (Cell density when infected) 35

36 Bioreactor Culture (1-BIIC/100-L Ratio) (Cell Growth and Viability During the Infection Process) Viable Cell Density ml Bioreactor B (Viable Cell Density) Bioreactor B (Viability) Viability (%) Time (Hours post infection) 0 36

37 Bioreactor A (1-BIIC/10-L Ratio) Bioreactor B (1-BIIC/100-L Ratio) (Cell Growth and Viability During the Infection Process) Viable Cell Density ml Bioreactor A (Viable Cell Density) Bioreactor A (Viability) Bioreactor B (Viable Cell Density) Bioreactor B (Viability) Viability (%) Time (Hours post infection) 0 37

38 Bioreactor B (1-BIIC/100-L Ratio) (Change in Cell Diameter During the Infection Process) Average Cell Diameter (um) 19.0 Bioreactor B: Average Cell Diameter Time (Hours post infection) 38

39 Bioreactor A (1-BIIC/ 10-L Ratio) Bioreactor B (1-BIIC/100-L Ratio) (Change in Cell Diameter During the Infection Process) Average Cell Diameter (um) 19.0 Bioreactor A: Average Cell Diameter Bioreactor B: Average Cell Diameter Time (Hours post infection) 39

40 Protein Expression in 7-L (5-L Liquid) Bioreactors Bioreactor A: 1-BIIC/ 10-L Volume Ratio Bioreactor B: 1-BIIC/100-L Volume Ratio Shake Flask Study (2006) Bioreactor A (2006) 10-L Bioreactor B (2006) 100-L Infection Time (hpi) M M M 7.9x10e5 cells/ml 8.6x10e5 cells/ml (Cell density when infected) 5.5x10e5 cells/ml 40

41 Summary Compared baculovirus stocks Cell diameter: Monitor the infection process Predict protein expression BIIC stocks are very stable Process is readily scalable 1-mL to either 10-L or 100-L in one easy step! Powerful tool Very flexible 41

42 Reference David J. Wasilko and S. Edward Lee. TIPS: Titerless Infected-Cells Preservation and Scale-up. BioProcessing Journal 5(3): (2006). Available at: 42

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