CHAMPAIGN, Ill. -- A respiratory virus that strikes hardest at young children and the elderly in nursing homes has lost a preliminary bout with a two-fisted enemy -- genetically modified cherry tomatoes containing an edible vaccine. The match took place in lab tests at the University of Illinois.

The greenhouse-grown tomatoes carried genetic coding of a fruit-specific promoter that targets a major protein on the outside envelope of the respiratory syncytial virus. In a recent issue of the European journal Transgenic Research, UI scientists reported that 22 of 25 mice eating the vaccine-containing tomatoes had increased antibody production in two of their immune systems.

Over 28 days, two sets of mice were fed five times with genetically modified or unaltered wild-type cherry tomatoes. Control mice fed unaltered tomatoes showed no protective response when subjected to the RSV antigen, a tamed form of the virus that still elicits immune responses.

"The results were very good," said Schuyler S. Korban, a professor of plant genetics. "They tell us that by feeding this tomato to mice, we can stimulate both the mucosal and serum immune systems."

Instead of injecting serum-based vaccines that stimulate an immune response in the bloodstream, edible vaccines could be used medicinally to build protection in the mucosal system -- immune cells along the nose, throat and mouth -- where the RSV virus first enters. The antibodies created by the immune response go after the F glycoprotein, which is responsible for the initial attachment of RSV to its target cells in the body.

"This paper establishes a vaccine approach to this virus, for which there currently is no effective vaccine," said corresponding author Dennis E. Buetow, a professor of molecular and integrative physiology. "For reasons that are not clear, injectable vaccines that have been attempted have not worked well in humans. Early attempts actually made the disease worse on subsequent i
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Contact: Jim Barlow
b-james3@uiuc.edu
217-333-5802
University of Illinois at Urbana-Champaign
30-Jul-2000