Obesity is associated with chronic inflammation, but does fat tissue offer protection during infection? Zhang et al. noticed that the fat layers in the skin of mice thickened after inoculation with the pathogenic bacterium Staphylococcus aureus (see the Perspective by Alcorn and Kolls). Mutant mice incapable of forming new fat cells were more susceptible to infection. The differentiating fat cells secreted a small-molecule peptide called cathelicidin, specifically in response to the infection. By contrast, mature fat cells produce less cathelicidin, and are thus less protective.
L.-j. Zhang, C. F. Guerrero-Juarez, T. Hata, S. P. Bapat, R. Ramos, M. V. Plikus, R. L. Gallo, Dermal adipocytes protect against invasive Staphylococcus aureus skin infection. Science 347, 67–71 (2015).[Abstract] [Full Text]