Starai awarded $1.5m to study Legionnaires' disease

Originally named from an outbreak at an American Legion convention in 1976, Legionellosis or Legionaires' disease is a severe type of pneumonia that affects only a small percentage of the population but can be fatal. UGA researcher Vincent Starai was recently awarded $1,503,565 by the National Institutes of Health to investigate how the bacterium that causes Legionellosis overcome the body’s defenses.

Starai is an assistant professor who holds a joint appointment with the departments of microbiology in the Franklin College of Arts and Sciences and infectious diseases in the College of Veterinary Medicine.

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Bacteria enter the lungs and are attacked by phagocytes, the white blood cells that fight infection. Normally phagocytes eat foreign particles, engulfing and breaking them into smaller fragments within a specialized compartment called the lysosome, but Legionella bacteria somehow block this process. Instead of fusing with the lysosome and disintegrating, the pathogen survives as a whole entity inside the phagocyte. The microbe then multiplies and reproduces inside the larger host cell. When the phagocyte finally dies, it releases a batch of new Legionella microbes ready to infect more phagocytes.

Over the next five years, Starai will look at proteins secreted by Legionella that prevent the host cell’s internal membranes from fusing with the lysosome. The fusion of these membranes is an essential step in the degradation of invading microbes.

“Legionella pneumophila produces and secretes a number of proteins that alter or inhibit membrane fusion,” said Starai. “Our goals are to study the mechanisms through which the bacteria alter the host cell environment.”



Starai has already determined that one particular Legionella protein, LegC3, directly interferes with the fusion of membranes. Under the NIH grant, his team will identify where LegC3 binds inside the phagocyte host cells, and how the protein manipulates host cell membrane fusion processes. The researcher will also identify the function of several other proteins produced by the bacteria and ascertain what role they play in the bacteria’s survival.

Persistant, as well as drug resistant, microbes and bacteria are increasingly the focus of research in infectious disease and researchers will look to gain insights and new models for studying other diseases from this work. Congratulations to Dr. Starai.