Dual lineages of langerhans cells cooperate for immune barrier recovery after skin injury

Summary: Abstract Body: Tissue-resident immune cells in the skin provide a first line of defense against infections. Langerhans cells (LCs) in the epidermis act as sentinels by surveilling skin and presenting antigens in lymph nodes. While LCs maintain well-organized spatial distribution in healthy skin, the mechanisms governing their de novo reconstitution following tissue damage remain elusive. Through longitudinal tracking of LCs and their progenitor cells in live adult mice, we discovered that most activated LCs near wounds (eLCs) stay local and directly contribute to restoring LCs in injured tissue rather than migrating to lymphatics. Simultaneously, monocytes infiltrate the epidermis during wound repair and differentiate into additional LCs (mLCs) that remain long after healing. While the inhibition of Cxcr2 signaling impairs eLCs contribution, mLCs compensate for this deficiency. Our findings reveal fundamental mechanisms of immune barrier recovery through coordinated repopulation by distinct LC lineages in damaged skin. Sangbum Park¹ 1. Medicine, Michigan State University, East Lansing, MI, United States. Stem Cell Biology, Tissue Regeneration and Wound Healing