FRIDAY, JUNE 22, 2018

New TB protein that stops production of immune cell protein discovered

Ohio State University researchers have determined that the tuberculosis bacterium contains a unique molecule on its outer surface that stops production of a protein in the immune cells that maintains it in a latent state.
The researchers found that lipomannan prevents the body's immune cells from producing tumor necrosis factor, Infection Control Today reports. When TNF is not produced sufficiently, the TB bacterium can grow unchecked and cause an uncontrolled active infection outside and inside the lungs.
"There are several unique components on the Mycobacterium tuberculosis outer cell wall that help it sneak into the lung relatively unnoticed," Larry Schlesinger, a professor and chair of the Department of Microbial Infection and Immunity at Ohio State University and the senior author of the study, said, according to Infection Control Today. "The more we can learn about how these cell wall structures influence the human immune response, the closer we can get to developing a more effective strategy to treat or even prevent an active tuberculosis infection."
The studies found that lipomannan can block TNF at the microRNA level. MicroRNAs are small segments of RNA that can regulate or fine-tune a gene's protein-building function. MicroRNAs have been implicated most frequently in the development of cancer and this is among the first studies to show that pathogenic bacteria can also influence their activation in immune cells.
"This really speaks to the power of the tuberculosis bacterium to adapt to the human host," Schlesinger said, Infection Control Today reports. "It has had centuries to develop a sophisticated way to deal with its encounter with the human. Fortunately, genomic technology is allowing us to identify microRNAs more and more rapidly, which might allow us to catch up with the TB bacterium and figure out a way to outsmart it."
Close to two billion people worldwide are thought to be infected with TB bacteria and an estimated one in 10 will develop active disease characterized by a chronic cough and chest pain.