Patent US3609259A successfully refreshed from Google Patents.
Patent US5219752A successfully refreshed from Google Patents.
US5219752A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for continuously culturing adherent animal cells
Assignee: Teijin Ltd
•
Filing: 1991-07-15
•
Granted: 1993-06-15
•
Expires: 2011-07-15
Abstract
Abstract Adherent 293 human kidney cells are continuously cultured in suspension in serum-free medium. Fresh medium is fed into a culture vessel and spent medium is withdrawn from the vessel. The 293 cells are maintained in small aggregates in suspension at a density of at least 3x106 cells/ml for 30 days. The formation of large cell clumps is prevented by maintaining the concentration of calcium in the serum-free medium at 0.002 mM to 0.3 mM.
Inventors
- 👤 Yoshiharu Takazawa
- 👤 Michiyuki Tokashiki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:22
CPC Classifications
C; C12; C12N; C12N5/00; C12N5/0018; C12N5/0037; C12N2500/00; C12N2500/05; C12N2500/10; C12N2500/12; C12N2500/14; C12N2500/20; C12N2500/24; C12N2500/25
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
128 words
A process for continuously culturing adherent animal cells selected from the group consisting of 293 strain derived from human fetal kidney cells and tranformants thereof, which cells are capable of secreting protein C in a serum-free medium, comprising: feeding fresh medium into a culture vessel, and withdrawing spent medium from the vessel, maintaining the said adherent animal cells in the serum-free medium in the said vessel in suspension, the said adherent animal cells being maintained in suspension at a density of at least 3×10 6 cells/ml, the concentration of calcium ion in the medium under the culturing conditions being maintained at 0.002 mM to 0.3 mM, and the protein C production level being at least 0.1 μg/10 6 cell/day for a period of about 30 days or longer.
Claim 2
Dependent Claim
128 words
A process for continuously culturing adherent animal cells selected from the group consisting of 293 strain derived from human fetal kidney cells and tranformants thereof, which cells are capable of secreting protein C in a serum-free medium, comprising: feeding fresh medium into a culture vessel, and withdrawing spent medium from the vessel, maintaining the said adherent animal cells in the serum-free medium in the said vessel in suspension, the said adherent animal cells being maintained in suspension at a density of at least 3×10 6 cells/ml, the concentration of calcium ion in the medium under the culturing conditions being maintained at 0.002 mM to 0.3 mM, and the protein C production level being at least 0.1 μg/10 6 cell/day for a period of about 30 days or longer.
Claim 3
Dependent Claim
27 words
The process of claim 1 in which the concentration of a calcium ion in the medium under the culturing conditions is maintained 0.002 mM to 0.25 mM.
Claim 4
Dependent Claim
31 words
The process of claim 1 or 2 in which most of the adherent animal cells in suspension are present as aggregated particles each containing 1.5 to 50 cells on an average.
Claim 5
Dependent Claim
31 words
The process of claim 1 or 2 in which most of the adherent animal cells in suspension are present as aggregated particles each containing 1.5 to 30 cells on an average.
Claim 6
Dependent Claim
24 words
The process of claim 1 in which the adherent animal cells in suspension are present at a density of at least 5×10 6 cells/ml.
Claim 7
Dependent Claim
44 words
The process of claim 1 in which the feeding of the fresh medium, and the withdrawal of the spent medium, into and from the culture vessel are carried out continuously or intermittently, and the liquid level in the culture vessel is maintained substantially constant.
Claim 8
Dependent Claim
25 words
The process of claim 1 in which the suspended state of the adherent animal cells in the culture vessel is maintained by agitation and/or aeration.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-06-14 | 1996-12-14 | 1997-06-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-06-14 | 2000-12-14 | 2001-06-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-06-14 | 2004-12-14 | 2005-06-15 | $7700.00 | Window Closed / Lapsed |