Off-site Storage of Cell Lines to Maintain Integrity

Cell lines are likely to suffer undesirable outcomes like senescence, genetic drift, and microbial contamination. Sometimes, even a well-equipped lab can experience equipment failure. Considering the value of an established cell line, replacements can be time-consuming and expensive. Therefore, labs mitigate risk by storing these cells in off-site facilities where they can be frozen down for long-term storage. This article describes how off-site cell line storage maintains integrity to ensure the safety and accuracy of critical cell lines.

The advantage of having an off-site location that is distant from your main storage facility can impact your ability to recover operations after natural disasters. Weather-related power outages or property destruction can have catastrophic impacts on your company’s research and product development progress. By creating diffuse redundancy in your storage, your organization can be positioned to recover from challenging situations.

What Does Proper Cell Line Storage Entail?

Off site cell storage methods focus on maintaining the integrity of cells within a freezing medium at extremely low temperatures. Cryoprotective agents are added to protect cell lines, preventing damage to the cells in the cooling and warming process. Cell vials are placed in special storage systems like ultra-low freezers and liquid nitrogen-cooled dewars during this process.

Where are these Cell Lines Used?

• Cell biology research
• Cell therapy
• Clinical trials
• Stem cell storage

Process of Cryopreservation

Cryopreservation uses liquid nitrogen to store products in lower temperatures, down to -196°C. Such temperatures slow down the biochemical processes in the cells to prevent damage and cell death. In addition, a slow, cryoprotectant-assisted freezing process can control freezing speed and prevent the development of damaging ice crystals.

Protein Production Scale Up in Hollow Fiber Bioreactor Systems

For many years, hollow fiber cell culture has been a unique platform that has many benefits including utilization of a closed system, single-use products, and 3D cell culture. Proteins can be difficult to express, especially those that are highly complex or glycosylated. Because of this, traditional cell culture methods can make protein production challenging, hence the need to use hollow fiber bioreactors. Here are details on how hollow fiber bioreactors increase protein production in cells.

How are Hollow Fiber Bioreactor Systems Different from Other Methods?

Four main characteristics distinguish hollow fiber cell culture from other methods:

• Cells do not use a plastic dish, microcarrier bead, or impermeable support for perfusing and bounding. Instead, they use a porous matrix giving an in vivo-like environment.
• Molecular weight cut-off (MWCO) is controllable.
• Surface-area-to-volume ratio is high, resulting in higher cell densities.
• Serum requirements for cell culture are greatly reduced.

How do Hollow Fiber Bioreactors Increase Protein Production

Hollow fiber bioreactors have thousands of semipermeable capillary membranes known as hollow fibers. These fibers are closely packed in a cylindrical cartridge with an inlet and outlet on each end. The tight packing of the fibers allows for the seeding and high-density growth of cells in the extra capillary space (ECS).

The cell culture media continuously flows within the fibers’ intracapillary space (ICS). With the help of the molecular weight cut off of the hollow fiber, you can control molecular flows. Therefore, small molecule nutrients and oxygen can flow through the fibers to the cells. The waste will move across the fibers to the intracapillary space, where it flows out.

In addition, the MWCO retains the larger molecular weight products like monoclonal antibodies, viruses, recombinant proteins, and cells inside the extra capillary space. The used media can be recirculated or removed from the system. The inflow and outflow of nutrients and waste from the cells within the 3D culture configurations creates an in vivo-like environment which is ideal for cell growth in high densities.

Advantages of Hollow Fiber Bioreactors

• Daily maintenance requires little time and does not require splitting of cells
• Cell cultures are maintainable for many months of ongoing production.
• Cell culture conditions improve protein assembly and folding.
• Small volumes can be harvested at a higher concentration for easy handling and efficient processing.
• Fewer cells are needed for seeding since no seed reactor is used.
• Minimal needs for cell lysis, less DNA contamination, and host cell protein.

A hollow fiber bioreactor system presents laboratories with opportunities to utilize the glycosylation and superior environment for folding that is provided by expression in mammalian cells. In addition, this method effectively produces concentrated products with reduced protein, DNA, RNA, and protease contamination.

Monoclonal vs. Polyclonal Antibodies

One of the key factors in determining the best service or strategy for producing antibodies is the decision of whether to choose monoclonal or polyclonal antibodies. At Cell Culture Company, we are your premier source for monoclonal antibodies customized for your individual needs.

Below are some of the benefits and drawbacks of each type of antibody:

Polyclonal Antibodies

The production of polyclonal antibodies occurs through various B cells in a host animal. These antibodies recognize numerous epitopes of a single antigen. Synthetic peptide and protein are the two most commonly selected antigens. It is possible to produce large quantities of polyclonal antibodies quickly, at low cost, and without the need for complex technology. These benefits make polyclonal antibodies ideal for research efforts.

Advantages of Polyclonal Antibodies

The benefits of polyclonal antibodies include:

• Quick production time
• Low cost
• Great tolerance to antigen changes (polymorphism, denature, and glycosylation heterogeneity)
• Strong target signal, including for protein with low expression
• Strong results in WB and IP/ChIP
• Detection more likely over a range of species
• Applicable for non-characterized antigens

Disadvantages of Polyclonal Antibodies

The potential drawbacks of polyclonal antibodies include:

• Some applications may have a higher reactivity and background noise
• Susceptible to variability from batch to batch

Monoclonal Antibodies

Unlike polyclonal antibodies which are generated from multiple immune cells, monoclonal antibodies are produced by identical immune cells which are clones of just one parent cell. The antibody in this case is very specific, recognizing just a single epitope of an antigen.

Monoclonal antibodies are usually generated through the fusion of myeloma cells with spleen cells from a mouse immunized with the target antigen to generate a hybridoma. Each one of these hybridomas is subsequently grown independently to generate colonies consisting of identical daughter cells. This process enables researchers to gather and compare the secreted antibodies of each hybridoma in order to choose the most advantageous ones to fulfill their ultimate goals of detection and purification.

Monoclonal antibodies are more ideal for applications for the development of antibody drugs or for projects requiring high specificity to the antigens.

Advantages of Monoclonal Antibodies

The various benefits of monoclonal antibodies include:

• Very specific recognition of only a single epitope of an antigen
• High level of consistency across experiments
• Cell lines of immortal hybridoma are theoretically capable of generating unlimited numbers of antibodies
• Ideal for affinity purification
• Low level of cross-reactivity and background noise

Disadvantages of Monoclonal Antibodies

Some of the potential drawbacks of monoclonal antibodies include:

• Longer time for production
• Higher cost
• More susceptible to epitope loss from antigen chemical treatment – but this may be countered by pooling at least two monoclonal antibodies.
• Potentially lower signal

For information about the monoclonal antibody production services we offer at Cell Culture Company, call us today at 763.786.0302 or send us a message through our contact form.