Cell culture: a strategic service at the source of our core business.
The 7 collaborators that are part of this unit are the guardians of a rich and unique cellular patrimony, a legacy that guarantees us complete autonomy in the production of monoclonal antibodies for immunohematology. Their role is preponderant, requires unfailing rigor and professionalism, and necessitates constant monitoring at all stages of production: clones deserve all the attention they can get, even on weekends and holidays!
Cell culture principle
The clones created and maintained by the cell culture service, were obtained between 1985 and 1991 through the use of 2 techniques:
- the ascite technique in which antibodies are produced by an intraperitoneal tumor induced in mice or rats (technique abandoned for a few years)
- and the technique of fusion of a B lymphocyte (from a mouse previously immunized against a expected antigen) and a myeloma cell (cell from an inactivated cancer line)
The lymphocyte produces antibodies and the mouse myeloma multiplies infinitely: the fusion of a human (or mouse) lymphocyte and a mouse myeloma gives a hybrid cell (or hybridoma) which recovers the 2 characteristics; :
- It will therefore secrete a specific monoclonal antibody in large quantities,
- while multiplying indefinitely as long as appropriate conditions (temperature, pH, oxygen) and strictly selected nutrients are provided.
This cell line is stored in nitrogen (-196°C) in ampoule form. It is the cell bank. From these ampoules, the production process, which lasts from 1 to 4 months, will allow the production of large quantities of monoclonal antibodies.
- Thawing of an ampoule and amplification in rollers
An ampoule of the cell bank is thawed and then amplified in rollers during 3 weeks (cell multiplication) in order to reach the expected cell concentration.
- Cell culture in fermentors or in rollers
If the planned quantity does not exceed 80 liters, the whole culture process remains in “Roller” technique. Otherwise, after 3 weeks, we prepare the inoculum under a laminar flow hood, to obtain sufficient biomass before transfer to the fermentor. All these operations are performed in ISO 7 and in sterile conditions with the following parameters: strictly regulated: pH (buffered medium + regulation thanks to CO2), temperature (37 ° C), oxygene, level inside and mixing. At the end of this step, we have sterile bags of supernatent that have to be clarified, concentrated and dialysed.
- Clarification by frontal filtration
Removing cells using 0,22µ filters
- Concentration by tangential filtration (hollow fiber)
Increasing the product performance and decreasing storage volumes.
Improving the conditions of conservation and activity.
- In process controls
The activity and specificity of each antibody is then tested as well as pH, osmolarity and protein level. All parameters can be adjusted.
- Long-term storage
The monoclonal antibody concentrates are stored in cold rooms at 4°C (2 years of validity) or -30°C (4 years of validity), depending on the seeds and on their use schedule. Our stocks will then be used for the products of our various ranges.