Page 653 - Veterinary Immunology, 10th Edition

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FIG. 21.2 The composition of the microbiota on canine skin. (From
Hoffmann AR, Patterson AP, Diesel A, et al: The skin microbiome in healthy and
allergic dogs. PLoS One 9(1):e83197, 2014.)

In mice, it has been shown that the skin microbiota influences
local inflammatory and T cell responses (Fig. 21.3). Epidermal Th17
+
and CD8 T cells are especially affected. The microbiota control the
balance between effector and regulatory T cells within skin tissue.
They influence keratinocyte production of IL-1 and its effects on
epidermal dendritic cells and thus control local T cell responses.
Skin bacteria can activate antigen-specific T cells across the intact

epithelium. However, the presence of Treg cells in neonatal skin
mediates tolerance to skin commensal bacteria at a time when the
skin is establishing its microbiota. Wound healing in germ-free mice
is significantly accelerated and scarring is much reduced. Skin

bacteria certainly contribute to the failure of some wounds to heal
promptly.

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