Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.563978
Title: Characterising lymphocyte trafficking across blood vascular and lymphatic endothelial cells
Author: Ahmed, Syed Rumel
ISNI:       0000 0004 2727 5960
Awarding Body: University of Birmingham
Current Institution: University of Birmingham
Date of Award: 2012
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Abstract:
The recruitment of peripheral blood lymphocytes (PBL) to sites of inflammation and their subsequent traffic into the lymphatic circulation is important in host defense. However, surprisingly little is known about their recruitment from the blood vasculature into inflamed tissue, and almost nothing about their egress from inflamed tissue via the lymphatic circulation. We showed that both human macrovascular and microvascular endothelial cells stimulated by TNF$$\alpha$$ and IFN$$\gamma$$, preferentially recruited memory T-lymphocytes (CD45RO positive cells) from a mixed pool of PBL. T-cells that had migrated across vascular endothelial cells subsequently utilised a combination of $$\beta$$1 and $$\beta$$2 integrins to traverse cytokine activated lymphatic endothelium. In addition we provide evidence that PGD2 was critical for the transmigration of lymphocytes through vascular endothelium. The process of trans-lymphatic migration was also significantly retarded in the presence of a function neutralising antibody against CCR7. Most importantly, we observed that memory T-cells showed a markedly enhanced capacity to migrate across lymphatic endothelium if they had first traversed a vascular endothelial cell barrier. We have shown that addition of exogenous PGD2 to isolated lymphocytes is able to restore the enhanced migration capacity of lymphocytes that have previously migrated through a vascular monolayer. The nature of the priming signal delivered by the process of migration across blood vessel endothelium remains to be fully identified, but is likely to be important in regulating the dynamics of an inflammatory response.