U.S. Army awards veterinary college researcher $1 million grant to develop vaccine

July 22, 2003

Blacksburg, Va. -- A bacteriologist in the Virginia-Maryland Regional College of Veterinary Medicine has been awarded a $1.06 million grant from the U.S. Army to develop a vaccine for tularemia.

Thomas J. Inzana, the Tyler J. and Francis F. Young Professor of Bacteriology at Virginia Tech and his research team in the college's Center for Molecular Medicine and Infectious Diseases have begun a four-year program to develop a vaccine and diagnostic test for tularemia, which is commonly known as "rabbit fever." The etiologic agent of tularemia is Francisella tularensis, which the Centers For Disease Control (CDC) classifies as a Category A bioterrorism agent.

Tularemia is an infection characterized by ulcers, swollen glands, fever, and flu-like symptoms. The organism can spread through the blood and lymphatic systems to infect the respiratory tract, where it can cause more serious health problems. Pneumonic tularemia may have about a 30 percent mortality rate, according to Inzana.

While not uncommon in wildlife throughout the United States, Inzana says, it is a relatively rare disease in people. Only about 100-200 cases of tularemia in humans are reported every year, Inzana says. The bacteria are transmitted to humans and animals by ticks and biting flies, or can be ingested by wildlife from drinking water. Humans are also infected through minor cuts or abrasions on the hands by handling infected animals.

The military is concerned about F. tularensis because of its heartiness and its virulence. Whereas about 10,000 Bacillus anthracis (anthrax) spores are required to cause disease, only about 10 F. tularensis cells are required to cause disease, according to Inzana. The organism could conceivably be aerosolized and used as a bioterrorism agent at home or abroad; hence, the military interest. A World Health Organization Committee estimated that aerosol dispersal of 50 kilograms of virulent F. tularensis over a city of 5 million people would result in 250,000 inhabitants becoming seriously infected, including 19,000 deaths.

One aspect of F. tularensis that makes it dangerous is its ability to resist host defenses, Inzana says. Unlike many bacteria, F. tularensis has the ability to survive inside some of the front-line defenders of the body's immune system. As phagocytic cells such as macrophages rush to attack and consume the invading pathogens, F. tularensis actually uses the macrophage as a home and multiplies within it.

While scientists do not yet know much about the biology of the organism, they do know that it has a capsule-like substance on its surface. Inzana, who recently developed and patented a vaccine for swine pleuropneumonia by mutating the DNA required for capsule synthesis by Actinobacillus pleuropneumoniae, and selecting for a non-capsulated vaccine strain, plans to apply his expertise in bacterial carbohydrate antigens to the new vaccine and diagnostic test development program.

His research team will isolate and characterize both the capsule and the outer membrane proteins that enable the organism to survive inside the macrophage. The key to creating an effective vaccine will be their ability to identify and stimulate the production of proteins that stimulate T-cells of the cellular immune system. It is hoped that antibodies to the capsule will help to clear the bacteria that are not yet in phagocytic cells, and that T cells of the cellular immune system will kill the cells harboring the bacteria.

Inzana is also working with professor of electrical and computer engineering Anbo Wang and research scientist Kristie Cooper of Virginia Tech's Center for Photonics Technology to develop photonic-based bio-sensors to detect the F. tularensis capsule or DNA in the field. Ultimately, that research could lead to the development of rapid pathogen sensing biosensors that could detect multiple pathogens on the battlefield.

Inzana is director of Clinical Microbiology in the Veterinary Teaching Hospital and a professor in the Department of Biomedical Sciences and Pathobiology. He is a diplomate of the American Board of Medical Microbiology and a Fellow of the American Academy of Microbiology. He has generated $4 million in extramural funding and been awarded three patents for intellectual properties arising out of research that has led to the development of vaccines for economically important agricultural diseases.

Virginia Tech

Related Immune System Articles from Brightsurf:

How the immune system remembers viruses
For a person to acquire immunity to a disease, T cells must develop into memory cells after contact with the pathogen.

How does the immune system develop in the first days of life?
Researchers highlight the anti-inflammatory response taking place after birth and designed to shield the newborn from infection.

Memory training for the immune system
The immune system will memorize the pathogen after an infection and can therefore react promptly after reinfection with the same pathogen.

Immune system may have another job -- combatting depression
An inflammatory autoimmune response within the central nervous system similar to one linked to neurodegenerative diseases such as multiple sclerosis (MS) has also been found in the spinal fluid of healthy people, according to a new Yale-led study comparing immune system cells in the spinal fluid of MS patients and healthy subjects.

COVID-19: Immune system derails
Contrary to what has been generally assumed so far, a severe course of COVID-19 does not solely result in a strong immune reaction - rather, the immune response is caught in a continuous loop of activation and inhibition.

Immune cell steroids help tumours suppress the immune system, offering new drug targets
Tumours found to evade the immune system by telling immune cells to produce immunosuppressive steroids.

Immune system -- Knocked off balance
Instead of protecting us, the immune system can sometimes go awry, as in the case of autoimmune diseases and allergies.

Too much salt weakens the immune system
A high-salt diet is not only bad for one's blood pressure, but also for the immune system.

Parkinson's and the immune system
Mutations in the Parkin gene are a common cause of hereditary forms of Parkinson's disease.

How an immune system regulator shifts the balance of immune cells
Researchers have provided new insight on the role of cyclic AMP (cAMP) in regulating the immune response.

Read More: Immune System News and Immune System Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.