Researchers discover how a novel type of antibody works against pneumococcal bacteria

Researchers at Albert Einstein College of Medicine of Yeshiva University have discovered how a novel type of antibody works against pneumococcal bacteria. The findings, which could improve vaccines against pneumonia, appear in the September/October issue of mBio, the online journal of the American Society for Microbiology.

Until recently, scientists thought that antibodies work against pneumococcal bacteria by killing them with the help of immune cells. However, several years ago, Einstein researchers discovered antibodies that were very effective against experimental pneumococcal disease in mice even though they were not able to induce bacterial killing by immune cells. In the current study, the researchers examined how these antibodies interact with pneumococcal bacteria and found that they cause the bacteria to clump together, enhancing a phenomenon called quorum sensing.

"Quorum sensing is a way that bacteria communicate with one another," explained senior author Liise-anne Pirofski, M.D., professor of (http://www.einstein.yu.edu/medicine/medicine.aspx) medicine and of microbiology & immunology, chief of infectious diseases at Einstein and Montefiore Medical Center, the University Hospital for Einstein, and the Selma and Dr. Jacques Mitrani Professor in Biomedical Research at Einstein. "Here, the ability of antibodies to enhance quorum sensing causes the bacteria to express genes that could kill some of their siblings, something called fratricide, and weaken the defense mechanisms that enable bacteria to survive and grow in a hostile environment."

Source: Albert Einstein College of Medicine