Posted by: ateedub | July 22, 2008

Vaccines Grown in Plants

Talk about way cool science. The Scientist is reporting on their blog that a vaccine grown in tobacco plants has successfully completed a phase 1 clinical trial. The paper comes out in PNAS tomorrow.

The vaccine treats non-Hodgkin’s lymphoma, and the use of plants as a medium is so important because the vaccine must be personalized to each individual patient – a typically expensive and time consuming process. I just wanted to expand on The Scientist’s explanation of how this works.

Each patient treated in the trial received a vaccine made up of proteins found on their own tumor’s B-cell surface Ig proteins. These antigens are expected to create an immune response against this protein found on the cancer cells, activating the body’s own immune system to fight the disease.

In this case, the researchers produced the human proteins using plants – by loading a plant virus with the patient’s Ig gene (which becomes the antigen). The virus replicates in the plant and makes millions of copies of the Ig protein which are then purified and injected into a patient.

In simple terms, the plants are the host for viruses producing human proteins. And not just generic human proteins, but proteins found on a specific patient’s tumor. This isn’t the first time someone has done this, but commercialization of this method hasn’t taken off yet.

Aside from the coolness factor, the benefit to doing this in plants (instead of animals) is speed and cost. From The Scientist:

Total time from biopsy to treatment averages three to four months, according to the paper. Animal-based vaccine production for B-cell lymphoma takes double that time, said Levy.

So a new methodology looks like it may be able to put treatments within reach of many more patients. Of course, this was only Phase 1, so there’s no data on how well it worked yet.


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