Patent US4983515A successfully refreshed from Google Patents.
US4983515A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Labeled cryopreserved cells for use as targets in cytotoxicity assays
Assignee: Bristol Myers Squibb Pharma Co
•
Filing: 1989-02-16
•
Granted: 1991-01-08
•
Expires: 2009-02-16
Abstract
Abstract Biological cells which are fluorophore-labeled can be stored frozen for a long period of time. After thawing the cells can be used as targets in fluorophore-release cytotoxicity assays.
Inventors
- 👤 Derrick T. Maley
- 👤 Agneta K. Nordstrom
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 04:17
CPC Classifications
C; C12; C12N; C12N1/00; C12N1/04; G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/5005; G01N33/5008; G01N33/5014; G01N33/5017
Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
18 words
Cryopreserved, fluorophore-labeled, viable biological cells which after thawing are suitable for use as target cells in cytotoxicity assays.
Claim 2
Dependent Claim
18 words
Cryopreserved, fluorophore-labeled, viable biological cells which after thawing are suitable for use as target cells in cytotoxicity assays.
Claim 3
Dependent Claim
18 words
Cryopreserved, europium-labeled, viable biological cells which after thawing are suitable for use as target cells in cytotoxicity assays.
Claim 4
Dependent Claim
18 words
Cryopreserved, europium-labeled, viable biological cells which after thawing are suitable for use as target cells in cytotoxicity assays.
Claim 5
Dependent Claim
13 words
Cells of claim 2 which are cells of a stable mammalian cell line.
Claim 6
Dependent Claim
8 words
Cells of claim 3 which are malignant cells.
Claim 7
Dependent Claim
9 words
Cells of claim 2 which are fresh tumor cells.
Claim 8
Dependent Claim
8 words
Cells of claim 2 which are non-malignant cells.
Claim 9
Dependent Claim
11 words
Cells of claim 6 which are coated with an exogenous antigen.
Claim 10
Dependent Claim
21 words
Cells of claim 2 wherein the europium is present in the cells as a chelate of europium and a chelating agent.
Claim 11
Dependent Claim
49 words
A method of producing the cells of claim 1 which comprises (a) labeling viable biological cells with a fluorophore, (b) washing the labeled cells with buffer, (c) suspending the cells in growth medium containing a cryoprotectant, and (d) freezing the cell suspension over a period of about one hour.
Claim 12
Dependent Claim
66 words
A method of producing the cells of claim 2 which comprises (a) treating viable biological cells with a buffered solution of a soluble compound of europium and a chelating agent to label the cells with europium, (b) washing the labeled cells with buffer, (c) suspending the cells in growth medium containing a cryoprotectant, and (d) freezing the cell suspension over a period of about one hour.
Claim 13
Dependent Claim
56 words
In a fluorophore-release assay for measuring cytotoxicity of a cytotoxic agent, wherein the agent is incubated with a suspension of fluorophore-labeled target cells and the release of fluorophore from the target cells is determined by fluorescence measurement, the improvement which comprises thawing the cells of claim 1 and using the thawed cells as the target cells.
Claim 14
Dependent Claim
64 words
In a europium-release assay for measuring cytotoxicity of a cytotoxic agent selected from effector cells, drugs and biological agents, wherein the agent is incubated with a suspension of europium-labeled target cells and the release of europium from the target cells is measured by time-resolved fluorescence, the improvement which comprises thawing the cells of claim 2 and using the thawed cells as the target cells.
Claim 15
Dependent Claim
71 words
In a europium-release assay for measuring cytotoxicity of effector cells selected from natural killer cells, lymphokine-activated killer cells, cytotoxic T-lymphocytes and tumor-infiltrating lymphocytes, wherein a suspension of effector cells is incubated with a suspension of europium-labeled target cells and the release of europium from the target cells is measured by time-resolved fluorescence, the improvement which comprises thawing the cells of claim 2 and using the thawed cells as the target cells.
References Cited (Backward Citations)
US4532203A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |