Circulating activated platelets reconstitute lymphocyte homing and immunity in L-selectin-deficient mice

Thomas G. Diacovo, Michelle D. Catalina, Mark H. Siegelman, Ulrich H. Von Andrian

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93 Scopus citations

Abstract

Peripheral lymph nodes (PLN) are critical for immunologic memory formation in response to antigens that penetrate the skin. Blood-borne lymphocytes first encounter such antigens after they home to PLN through a multi-step adhesion process that is normally initiated by L-selectin (CD62L) in high endothelial venules (HEV). Since naive T cells can not enter PLN normally in L-selectin-deficient mice, a delayed type hypersensitivity response to cutaneously applied antigen cannot be mounted. In this study, we report that the administration of activated platelets into the systemic circulation of L-selectin knockout mice restores lymphocyte trafficking to PLN, and reconstitutes T cell-mediated immunity in response to a cutaneous antigen. These effects required platelet-expressed P-selectin that allows activated platelets to transiently form a bridge between lymphocytes and HEV, thereby enabling lymphocytes to undergo subsequent β2 integrin-dependent firm adhesion. These profound effects of platelet-mediated cell-cell interactions on lymphocyte trafficking and formation of immunologic memory may impact on a variety of autoimmune and inflammatory conditions.

Original languageEnglish (US)
Pages (from-to)197-204
Number of pages8
JournalJournal of Experimental Medicine
Volume187
Issue number2
DOIs
StatePublished - Jan 19 1998

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ASJC Scopus subject areas

  • Immunology and Allergy
  • Immunology

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