A diverse group of immune cells called pulmonary macrophages patrol the lungs, consuming bacteria and particles while occasionally triggering inflammation. Alveolar resident macrophages (AMs) and bone marrow (BM)-derived macrophages are the two primary subgroups of macrophages that coexist during homeostasis. Due to changing expression of cell surface markers during lung inflammation, it is difficult to identify and characterize these subsets.
Now, Timothy Blackwell, MD, and associates have created a method to mark AMs and BM-derived macrophages independently using lipophilic fluorescent dyes that adhere to cell membranes (intratracheal injection and tibial injection). Following intratracheal injection of the bacterial toxin LPS, they used the method to monitor the distinct macrophage subsets and analyze the gene expression profiles.
The research, which was published in The Journal of Immunology, demonstrates that during LPS-induced inflammation, the new approach successfully distinguishes between AMs and BM-derived macrophages. According to the scientists, it should be helpful for researching macrophage subgroups during lung inflammation, infection, and injury.
Wei Han, MD, Yang Liu, PhD, Raphael Hunt, MS, Sergey Gutor, PhD, and Ana Serezani, PhD were all co-authors of the study. The Department of Veterans Affairs and the National Institutes of Health (grant HL151106) provided funding for the study.