Fig. 5: IL8-dependent directional migration of neutrophils towards infected epidermis.

a Reconstructed 3-D confocal image showing the spatial distribution of infiltrating neutrophils (red, CD15) and HSV-infected epidermis (green) in the skin-on-chip. Neutrophils were perfused through the microvascular network 1 h after the epidermis was infected with HSV-1 K26 (10⁶ PFU). Scale bar: 100 µm. b Top left: Projected cross-sectional view of neutrophil (red) migration into the dermal space toward HSV-infected (green) epidermis in the skin-on-chip. Dashed line indicates the vessel wall. Top right: Horizontal view of infiltrating neutrophils in the HSV-1-infected epidermis. Bottom row: enlarged views of the dashed boxes showing close contacts between neutrophils and infected keratinocytes. c Quantification of neutrophil distribution in z distance. Z = 0: neutrophils inside the vessel; Z > 0: neutrophils migrated out of vessel and moved up toward the infected epidermis. Z < 0: neutrophils migrated out of vessel and moved down, away from epidermis. d Quantification of IL-8, IL-6, RANTES, and TNFα protein expression in culture medium after 5 h of mock or HSV-1 infection (n = 2). e Neutrophil extravasation in response to HSV infection in skin-on-chip either mock-treated (left) or treated with anti-IL-8 neutralizing antibody (right) for 6 h prior to infection. Neutrophils were perfused through the microvascular network 1 h after the epidermis was infected with HSV-1 K26 (10⁵ PFU). Images taken 20 h post infection. Inset images show neutrophil morphology. CD15 (red), DAPI (blue). Scale bar: 100 µm. f Quantification of neutrophils that adhered to the vessel wall or transmigrated out of the vessel (n = 2). Data are provided in a Source data file.