NEW YORK (June 14, 2007) -- In a finding that could have important implications for HIV vaccine research, new research at Weill Cornell Medical College illuminates the ways in which the body prevents its mucosal surfaces from being overwhelmed by bacteria.
Bacteria, most of them "friendly," appear in huge quantities along the intestinal wall, the mouth, nose and throat, and the anal and urogenital tracts. Now, groundbreaking research at Weill Cornell shows that the epithelial cells that line these mucosal surfaces help guide the immune system's efforts to keep bacteria in check.
"That's a wholly new finding, since most biologists think of epithelial cells as a barrier cell -- not as a highly active player in immune function," explains senior researcher Dr. Andrea Cerutti, associate professor in the Department of Pathology and Laboratory Medicine at Weill Cornell Medical College.
"Armed with this knowledge, perhaps we can harness the mechanisms we've discovered to ward off more dangerous pathogens that use mucosal surfaces as their point of entry into the body -- viruses such as HIV, or rotavirus, the diarrhea pathogen that kills millions of children in poor countries each year," he explains.
His team published their findings in the June issue of Immunity.
The new research focused on a type of protective immune system antigen called immunoglobulin A (IgA), which is produced by immune system B cells. In humans, IgA takes two forms -- IgA1 and IgA2.
IgA2, especially, is found in high concentrations along mucosal sites wherever friendly, "commensal" bacteria abound, such as in the intestine where these germs aid in digestion. "Of course, left unchecked, even these bacteria could overrun the gut and cause harm," Dr. Cerutti says. "But somehow the immune system keeps them in balance, giving us the bacteria's benefits with no dangers."
IgA2 is a key player in this balancing act, but since there are
Contact: Andrew Klein
New York- Presbyterian Hospital/Weill Cornell Medical Center/Weill Cornell Medical College