September 22, 2011 -- (Bronx, NY) -- 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."
The National Foundation for Infectious Diseases estimates that 175,000 people are hospitalized with pneumococcal pneumonia in the United States each year. In addition, pneumococcal bacteria cause 34,500 bloodstream infections and 2,200 cases of meningitis annually.
There are two pneumococcal vaccines: one for adults and one for infants and children. The pediatric pneumococcal conjugate vaccine has dramatically reduced the incidence of pneumococcal disease in children and adults by protecting vaccinated children and by reducing person-to-person transmission of the bacterium, (a phenomenon known as herd protection). However, the vaccine doesn't cover all strains of disease-causing pneumococcus, and the vaccine currently used for adults does not prevent pneumonia. Fortifying current pneumococcal vaccines to stimulate antibodies that make pneumococcal bacteria less able to protect themselves -- or kill them directly -- could enhance their effectiveness.
The paper is titled "Antibodies to Streptococcus pneumoniae Capsular Polysaccharide Enhance Pneumococcal Quorum Sensing." Co-authors include lead author Masahide Yano, Ph.D, Shruti Gohil, M.D., J. Robert Coleman, Ph.D., and Ph.D. candidate Catherine Manix, all of Einstein. The research was supported by research and training grants from the National Institute of Allergy and Infectious Diseases of the National Institutes of Health.
About Albert Einstein College of Medicine of Yeshiva University
Albert Einstein College of Medicine of Yeshiva University is one of the nation's premier centers for research, medical education and clinical investigation. During the 2010-2011 academic year, Einstein is home to 724 M.D. students, 256 Ph.D. students,122 students in the combined M.D./Ph.D. program, and 375 postdoctoral research fellows. The College of Medicine has 2,770 full time faculty members located on the main campus and at its clinical affiliates . In 2010, Einstein received nearly $200 million in support from the NIH. This includes the funding of major research centers at Einstein in diabetes, cancer, liver disease, and AIDS. Other areas where the College of Medicine is concentrating its efforts include developmental brain research, neuroscience, cardiac disease, and initiatives to reduce and eliminate ethnic and racial health disparities. Through its extensive affiliation network involving five medical centers in the Bronx, Manhattan and Long Island – which includes Montefiore Medical Center, The University Hospital and Academic Medical Center for Einstein – the College of Medicine runs one of the largest post-graduate medical training programs in the United States, offering approximately 150 residency programs to more than 2,500 physicians in training. For more information, please visit www.einstein.yu.edu.