Vaccine proves protective in preliminary studies.(sepsis)

2002 DEC 11 - (NewsRx.com & NewsRx.net) -- A group of researchers from the Scripps Research Institute (TSRI) have designed a vaccine that might be used to protect against the pernicious consequences of severe sepsis, an acute and often deadly disease that is estimated to strike 700,000 Americans a year and millions more worldwide.

Though the new vaccine has not yet been applied to clinical trials in humans, it has worked well in preclinical studies, the results of which the team reported in Angewandte Chemie.

"The vaccine provided outstanding protection," said author Kim Janda, PhD, who holds the Ely R. Callaway, Jr. Chair in Chemistry at TSRI.

Sepsis, also known as septic shock and systemic inflammatory response syndrome, is characterized by shock to one's organs following poisoning with endotoxins - chemical components of certain bacteria. The endotoxin molecules themselves are not particularly harmful, but the way that the immune system reacts to them is.

When bacteria like the deadly N. meningitides invade the body, they trigger the immune system to stage a biochemical defense. One of the ways that the body initially responds to such an infection is to recruit white blood cells, like macrophages, which engulf the pathogens and destroy them. The macrophages also fight the pathogens by producing chemicals at the site of an infection that induce inflammation.

However, there is a limit to how much inflammation a body can take. If the infection is widespread, the systemic endotoxin levels can be so high that the macrophages respond by producing a lethal amount of inflammatory chemicals. One of these chemicals is called tumor necrosis factor alpha (TNF-alpha).

The prognosis for sepsis is dire. It can affect many parts of the body, from the bones to the brain, and death due to septic shock can occur in a matter of hours. According to the National Institutes of Health, 2% of all hospital admissions suffer from sepsis, and its typical case-fatality rate is around 30%. According to the Centers for Disease Control and Prevention, sepsis is one of the 10 leading causes of both infant and adult mortality in the United States, and, in 1999, directly caused more than 30,000 deaths.