B-cell lymphoma is a cancer in which an immune cell reproduces uncontrollably. The particular malevolent cell has a unique protein marker, which makes each case different. Currently, patients are treated using chemotherapy and radiation with mixed success.

Personalized vaccines use the cancerous cell's marker to trigger an immune response against the cancer.  Oncologist Ronald Levy of Stanford University says that these protein vaccines can be grown in tobacco plants with the help of a special tobacco plant virus.

Starting with a normal tobacco plant, Levy says all that is needed is to "scratch one leaf and add the virus solution." The virus infects the whole plant and in about a week "you can harvest the leaves and get the protein [vaccine] out."

Plants are not the only way to produce vaccines. Previous work manipulated mice to make vaccines, but the process is expensive and time-consuming. While bacteria may be able to produce the vaccines more quickly, they still require special incubators and costly facilities. Levy says that plants, on the other hand, do not need such expensive equipment so they are "very suitable for small batches of many different products."

Plant-made vaccines may also be more effective than traditional mice-produced vaccine. Plants fold proteins differently than mice cells, and they also attach different sugars to the proteins. Both of these might give plant-made vaccines "more ability to attract the immune systems' attention."

Levy and his colleagues demonstrate that plant-grown vaccines are safe in humans and provoke an immune response. They now plan to investigate how effectively the vaccines treat lymphoma. Levy notes the irony that the tobacco plant — responsible for cigarettes and, thereby, lung cancer — may now offer hope treating another type of cancer.

This work is in the July 22 edition of the Proceedings of the National Academy of Science.