How exactly are cells used in vaccine development?
The use of cells to develop vaccines can be broken down into two pieces. First, production. Second, testing.
Biologics, things like antibodies and viruses, need to be grown in living organisms by definition. Non-biologics can be produced without cells. Cells are given the instructions for the biologic and given time to produce a lot of it before harvesting. This is all done in dishes/flasks/bioreactors depending on the scale. After harvesting, there is a whole series of filtration/purification steps completed to produce a substance that contains no remnants of the cell line used.
Viral-vector based vaccines require cells to be produced. The mRNA-based vaccines do not require cells to grow their components.
After production and purification comes testing! No matter how a vaccine is produced, it is tested in cell lines to characterize it before moving into animals. This process provides invaluable information that informs scientists about the potency of a drug (how well it does what it should) and any potential toxicity (how safe does it appear to be).
Immortalized cell lines are populations of cells modified to grow indefinitely for the purpose of consistency in the lab. I describe which lines are known to be used in some of the most talked about vaccines and the ethical discussion around their origins.
I believe transparency is key to having open conversations. While it is not my call to decide how you feel about where the lines came from, it is my responsibility here to make sure you are fully informed about how and why they are used and that they do not exist in the final vaccine formulation.
I also specifically include HeLa Cells because they are the most widely used immortalized cell line and the story of Henrietta Lacks should be told at every opportunity to honor her.
Posted on Instagram on March 6, 2021.