HOUSTON -- A new vaccine may provide the first effective protection against Lyme disease, say medical researchers in Texas and Maryland.
Scientists at Texas A&M University's Institute of Biosciences and Technology in Houston and MedImmune, Inc., in Gaithersburg, Md., say tests in laboratory animals suggest the new candidate vaccine could protect humans against Lyme disease even after they've been infected with the bacterium that causes the disease.
If tests of the vaccine in laboratory animals continue to be promising, MedImmune plans to request FDA approval to begin studies in humans in 1997, company officials say. MedImmune scientists will describe the results of the MedImmune-Texas A&M studies during the Seventh International Congress on Lyme Borreliosis Friday (June 21) in San Francisco.
Lyme disease is caused by a bacterium known as Borrelia burgdorferi. The spiral-shaped organism is found in tiny ticks called deer ticks, which pass the disease to humans and animals when the ticks bite them to feed on their blood.
The new vaccine is based on a protein from the Lyme-causing bacterium discovered by IBT molecular biologists Magnus Hook and Betty Guo in 1993. Hook is Neva and Wesley West Professor and director of the institute's Center for Extracellular Matrix Biology and Guo is a graduate student in his laboratory.
In 1995, they isolated the gene responsible for producing the protein and began collaborating with MedImmune, Inc. to test a vaccine based on the protein in laboratory animals.
This candidate vaccine appears to offer some advantages over other potential vaccines based on different proteins from the Lyme-causing organism, the Texas A&M researchers say.
"Unlike antibodies to the other protein, these antibodies can clear the bacterium after the infection has begun," says Guo.
The protein -- decorin-binding protein, or DBP -- attaches, or binds, to a protein known as decorin found in human skin and cartilage tissue. Antibodies to DBP produced by the immune system appear to provide complete protection against disease caused by the Lyme-causing bacterium, the scientists say.
Unlike potential vaccines based on other proteins from the Lyme bacterium, the DBP-based candidate vaccine appears to allow the immune system to clear the disease-causing organisms from the body even if administered as long as four days after infection with the bacterium.
Lyme disease is named for the town of Lyme, Conn., where medical authorities identified the first cases of the disease. In humans, its early symptoms often include a circular rash surrounding the bite of a tick, fever, headache and nausea.
When diagnosed early, it is easily and effectively treated with antibiotics. Untreated, however, its complications can range from arthritis-like joint pain to neurological, heart and liver complaints.
Lyme disease has been reported in 49 states, including Texas. Nationally, more than 10,000 new cases are reported each year, public health authorities say.
An exclusive licensing agreement to the United States and international patent applications for DBP owned by The Texas A&M University System was negotiated by the A&M System's Technology Licensing Office. Under the terms of the agreement, the A&M System will receive payments from MedImmune upon the accomplishment of product development milestones and royalties on sales once the vaccine receives FDA approval.
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