Early after skin wounds, innate immune cells, including natural killer (NK) cells, infiltrate the wound bed within the first 24 hours. The application of widely used calcium alginate dressings facilitates cutaneous healing by releasing Ca2+ ions into the exudate and locally enriching its level. Since Ca2+ ions have been identified as one of the main activators of NK functions, the effects of two alginate dressings, Algosteril® (Algo, pure Ca2+ alginate) and Biatain® Alginate (BIA, Ca2+ alginate with CMC), and CaCl2 solution were compared on NK cell cytotoxicity by analyzing K562 lysis and CD107a expression as well as on their IFN-γ and TNF-α production. NK cells were isolated from healthy donor blood and incubated during 18h with a 3mM CaCl2 solution or conditioned media (CM) prepared from the alginate dressings according to ISO 10-993 standard. Our results showed that CaCl2 solution or the pure calcium alginate dressing Algo-CM, but not BIA-CM, significantly enhanced the capacity of NK cells to kill their targets. Algo-CM increased NK cell activation by degranulation of cytotoxic CD56dim NK cells, as shown by CD107a expression. IFN-γ and TNF-a production was shown to be mediated by a Ca2+-independent mechanism. Extracellular Ca2+ influx into NK cells was also induced in response to the pure calcium alginate Algo, suggesting a role for Ca2+ permeable plasma membrane channels. Altogether, the present data showed that the pure calcium alginate dressing Algosteril® enhances NK cell activity. This underlined a mode of action of this medical device in cutaneous wound defense through the activation of NK cell functions in response to the released Ca2+. They also highlighted the non-equivalence between alginate dressing activities.

ESDR615 - Modulation of NK cell activation by calcium from alginate dressings in vitro

The scientific meeting of the European Society for Dermatological Research (ESDR) is held yearly, usually in September. With an international attendance of more than 1000 skin scientists from around the globe, the four-day event includes short oral presentations from peer-reviewed abstracts, keynote lectures from international experts, sponsored symposia, satellite programs, educational events as well as an important focus on posters, networking and building collaborations amongst scientists. For more information about this year’s meeting visit our website.