For your own good >. A gene-based vaccine protect rainbow trout fish against a virus.
A new type of vaccine provides a plan to build antibodies, bypassing some of the steps require traditional vaccines. So far, the technique has been applied to the protection of fish, but it might one day be adapted for human gene based vaccines.
Traditional vaccines are made from inactivated pathogen. Although they are harmless, the body reacts by developing antibodies that protect then against a true infection. But these vaccines have a low risk of an adverse reaction. The new DNA vaccines provide genes which encode normally found on an infectious agent proteins. The body accumulates antibodies to these proteins, antibodies that defend against later attack by the pathogen carrying proteins. DNA vaccines, however, often do not stimulate the production of more antibodies than conventional vaccines.
Looking for a better way to repel the invaders, Niels Lorenzen the Danish Veterinary Laboratory in Århus, Denmark, speculated that the genes for the antibodies themselves could be delivered directly. His team tested this idea by isolating a gene for an antibody that protects rainbow trout against a virus called VHS. They injected the gene into the muscle of young trout that has never been exposed to VHS.
After 12 days, the researchers found the antibodies circulating in the blood of fish. After 6 more days, they exposed the fish to the virus. Over 0% of treated fish fought the infection. untreated trout, 80% died, the researchers report in the November issue of Nature Biotechnology . The gene vaccine did not protect the fish indefinitely, however; 39 days after injection, the fish showed signs of inflammation at the injection site, and muscle cells that had produced the antibody began dying.
The study is a "significant step" towards the use of antibody genes to create temporary immunity against pathogens, said Scott LaPartra of Clear Springs Trout Company in Idaho. Fish farms are particularly vulnerable to infectious diseases, because the fish are in such close quarters. An antibody gene vaccine could provide a rapid immunity once an outbreak starts. Lorenzen and hope that research on the protection of fish will be useful for human applications, particularly in people with deficient immune system does not respond strongly to standard vaccines.
Related Sites
The Danish Veterinary Laboratory
For more information on DNA vaccines
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