Dr. Stephen Keith Chapes's laboratory

"Our laboratory focuses on macrophages and other inflammatory cells. In particular, we are interested in processes that induce immunosuppression—like cancer therapy, AIDS, and stressful environments—to determine how inflammatory cells are affected. The first of two current projects explores cellular immunity to Ehrlichia chaffeensis. People with AIDS have suppressed numbers of CD4+ helper T-cells and develop opportunistic infections, like ehrlichiosis, as well as cancers such as Kaposi's sarcoma. In addition, depressed immune functions result from cancer surgery and chemotherapy, rendering patients more susceptible to ehrlichiosis. We are working to understand how helper T-cells and other immune system components control ehrlichial infections by using immunosuppressed mice to determine what components of the immune system are important to resistance to this commonly-found, tick-borne pathogen.

Our second project attempts to determine how macrophage hematopoiesis and differentiation are altered by space flight. Cancers of the immune system are among the most devastating because the cancer cells are the immune cells that the body needs for resistance to infectious diseases. Hematopoiesis involves rapid cell division. Mutations during this stage of cell development can be particularly harmful because the cells are programmed for replication and trafficking throughout the body. Therefore, understanding the process of hematopoiesis, even during space flight, will help in the understanding of the development of white blood cell cancers."