Adhesion Molecules in Skin - Adhesion Molecules - page 293

HECA human endothelial cutaneous antigen

IFN-γ interferon gamma

IgSF immunoglobulin superfamily

IL interleukin

JNK c-Jun N-terminal kinase

LC epidermal Langerhans cells

LFA lymphocyte function associated antigen

LN lymph node

NF-κB nuclear factor kappa B

PECAM platelet endothelial cell adhesion molecule

PNAd peripheral node addressin

PRR pattern recognition receptors

PSGL-1 platelet selectin glycoprotein ligand-1

T CM central memory T cells

T EM ef ector memory T cells

T REG regulatory T cells

TCR t cell receptor

Key Facts about Immunosurveillance and Leukocyte
Migration to Cutaneous Tissues

1. Leukocytes that bear selectin ligands can tether and roll across cutaneous
capillary endothelial surfaces that express selectins. Cells that do not have
an appropriate ligand will move through the vessel too quickly to interact
with the vascular surface and are thus not eligible for recruitment.

2. Rolling cells sample the vessel surface for activation molecules. If the
cells encounter a chemokine for which they have the appropriate counter
receptor, they become activated, upregulate integrin avidity and form i rm
attachments.

3. Firmly attached cells, in turn, must successfully negotiate interaction
with the endothelial cells, junctional proteins and extracellular matrix
components to ef ectively transmigrate and move into the tissue.

4. Each step in this cascade is thus required, but individually insui cient,
providing multiple checkpoints for regulation.

5. All the major ligands necessary for recruitment of circulating leukocytes
to the skin are expressed constitutively on the endothelium of cutaneous
capillaries to ensure continuous surveillance even under non-inl ammatory
conditions.