PLoS Pathog. 14, e1007244 (2018)

Clearance of skin infections caused by the human pathogenic bacteria MRSA involves production of protective cytokines and chemokines and formation of an abscess composed of neutrophils and extracellular matrix components that encapsulate bacteria to prevent their dissemination to the bloodstream and to other organs. However, the events of the early defense response upon an encounter with the bacteria are poorly understood. Brandt et al. examined LTB4, a lipid signaling molecule that has been shown to be produced early upon phagocyte activation, as a potential candidate involved in shaping in the immune response. The authors used mice with deleted 5-LO, an enzyme in the LTB4 biosynthetic pathway, or those deficient for the high-affinity LTB4 receptor BLT1 to conclude that LTB4 is required beginning at the time of infection to promote neutrophil chemotaxis (potentially as a chemoattractant), abscess formation, and thus control of bacterial load. They also defined a novel role for skin-resident macrophages in regulating abscess formation. These results, combined with the observation that an ointment containing LTB4 can enhance the efficacy of a topical antibiotic against MRSA, suggest that LTB4 could be useful to boost immunity against MRSA infection.

Credit: PLoS