TCell Migration and Extravasation

Following activation, T cells leave the lymph node and start trafficking via the bloodstream to the dermal vessels (Fig. 5.1b). Stimulation by keratinocyte-derived cytokines (IL-8, CCL27) leads to increased expression of adhesion molecules, including E-selectin and ICAM-1, in the post-capillary venules of inflamed skin. E-selectin is the target for cutaneous lymphocyte antigen (CLA) on the T-cell surface. Binding of CLA to E-selectin, as well as the interaction of the lymphocyte chemo-kine receptor (CCR10) with its ligand CCL27, slows circulating lymphocytes and causes their "rolling" along the endothelial wall.

As a result of increased exposure to chemokines, the affinity of LFA-1 for ICAM-1 is increased, probably mediated by a conformational change in the LFA-1 molecule. Bound T cells flatten and pass through the epithelium into the surrounding tissue - a process known as diapedesis. Once they have left the venule, T cells respond to chemokines; drawing them towards the site of inflammation in the dermis, and from there into the epidermis.

Was this article helpful?

0 0
Natural Treatments For Psoriasis

Natural Treatments For Psoriasis

Do You Suffer From the Itching and Scaling of Psoriasis? Or the Chronic Agony of Psoriatic Arthritis? If so you are not ALONE! A whopping three percent of the world’s populations suffer from either condition! An incredible 56 million working hours are lost every year by psoriasis sufferers according to the National Psoriasis Foundation.

Get My Free Ebook

Post a comment