A WMed researcher who has spent more than 10 years studying B cells and their immune response in the body has received funding from the National Institutes of Health to study the influence that sex has on health and disease.
A research project by Nichol Holodick, PhD, titled “Sex Determines Age-related Changes in the Repertoire and Function of Natural Antibodies Protective against Streptococcus pneumoniae with Increasing Age,” has been supported with a four-year, $1.51 million grant that was awarded to WMed in September by the National Institute of Allergy and Infectious Diseases, which is part of the National Institutes of Health (NIH).
Dr. Holodick studies a specific subset of white blood cells, B cells, that make proteins called antibodies, which are able to bind to and facilitate the clearance of bacteria. Her research project focuses the loss of protective antibodies against pneumococcal bacteria with advancing age and the role of sex in determining differences in protection from infection between males and females.
“B-1 cells make natural antibodies, which are present all the time,” Dr. Holodick said. “They make this antibody even before they see the bacteria, so they’re special in that way. These natural antibodies are part of our first line of defense.”
Normally a person requires two weeks to make specific antibodies against an infection, but B-1 cells provide antibodies essential in protection from infection during the time required for the immune system to mount a specific response over a two week period, Dr. Holodick said. B-1 cell natural antibodies are essential for protection during the early phases of bacterial infection. What Dr. Holodick has found in previous studies is that natural antibodies change depending on age and sex. The grant will help Dr. Holodick understand how, as we age, sex plays a role in the maintenance of protective natural antibody production.
Studies have shown that infection of Streptococcus pneumoniae, a type of bacteria that causes pneumonia, claims the lives of men over the age of 65 eight times more frequently than males aged 5 to 49, Dr. Holodick said. B-1 cells provide protection from the bacteria through the production of natural antibody, but her studies have shown the antibody in aged male mice does not protect against Streptococcus pneumoniae infection.
“I’m interested in how B-1 cells and the antibodies they produce change over time,” Dr. Holodick said. “Why with age are males in particular less protected from streptococcus pneumonia? I’m interested in what changes happen over time leading to less effective natural antibody. The grant will help to understand one angle, or one arm, of what might be going on, and that relates to differences between males and females. The grant focuses on how estrogen affects B-1 cell production of natural antibodies capable of providing protection against S. pneumoniae in the aged.”
Dr. Holodick’s research will have a significant impact on the health of the people of Michigan, especially the elderly, said Greg Vanden Heuvel, PhD, the medical school’s Associate Dean for Research.
“We are delighted with the success of Dr. Holodick,” Dr. Vanden Heuvel said. “She is a leader in the field of Immunology and a member of the Center for Immunobiology, one of the foremost centers for the study of B1 cells in the country.”