St. Jude discovers cellular vehicle that transports pneumonia

St. Jude Children's Research Hospital (ALSAC)
Friday, 15 September 2000

Goal of researchers is to develop an effective pneumococcal vaccine for children

Pneumococcal disease is the most prevalent invasive disease of children in terms of both deaths and life-threatening complications. One such pneumococcal disease, pneumonia, kills 3.7 million children each year and is the most deadly childhood disease worldwide. Existing vaccines and those currently in clinical trials are not effective in protecting young children. Seeking strategies for an effective vaccine, a team of researchers from St. Jude Children's Research Hospitalâ – led by Elaine Tuomanen, M.D. – studied how the bacterium Streptococcus pneumoniae traffics from the throat to the blood stream. The findings of their study were published in the journal Cell on September 15.

Researchers at St. Jude have long known that nearly everyone has a harmful bacterium called Streptococcus pneumoniae or pneumococcus sitting quietly in the back of their throats. But these same researchers were perplexed why only one in 100 people actually become sick with pneumococcal illnesses, such as pneumonia, ear infections, bacteremia (bacteria found in the blood), and meningitis.

The St. Jude research team looked at multiple human cell structures in their quest to identify how the infectious microbe travels from an innocuous place in the throat to the blood stream where the disease becomes active. They discovered that the bacterium hijacks the human system for exporting Immunoglobulin A onto the surface of the throat, and drives it backwards into the blood stream. "When the human cell mounts a defense response, Immunoglobulin A comes to the cell surface. There the bacterium finds it very handy to bind to and dive back into the cell following this molecular chaperone," said Tuomanen. Further research showed that the bacterial binding partner is choline-binding protein A, which St. Jude is developing as a potential vaccine candidate to block pneumococcal invasion.

St. Jude Children's Research Hospital, in Memphis, Tenn., was founded by the late entertainer Danny Thomas. The hospital is an internationally recognized biomedical research center dedicated to finding cures for catastrophic diseases of childhood. The hospital's work is supported through funds raised by the American Lebanese Syrian Associated Charitiesâ (ALSACâ ). All St. Jude Hospital patients are treated regardless of their family's ability to pay. ALSAC covers all costs of treatment beyond those reimbursed by third party insurers, and total costs for families who have no insurance.

For more information, or to contact St. Jude Children's Research Hospital (ALSAC), see their website at: www.stjude.org