Murine CD8alpha+ Dendritic Cell Migration
Murine CD8alpha+ dendritic cells (DC) are antigen-presenting cells with tolerogenic properties, including ability to prolong allograft survival. Little is known, however, regarding their migratory ability, either in vitro or in vivo. Limited work to date has yielded inconsistent findings, and potential impediments to use of this subset to promote tolerance induction are reported discrepancies regarding their ability to home to secondary lymphoid tissue. Despite functional differences from classic CD8alpha- DC, the two subsets exhibit similar phenotypes and commonly coexist in the same tissues, suggesting expression of similar homing molecules/receptors. The central hypothesis underlying these studies was that CD8alpha+ and CD8alpha- DC have equal ability to respond to migration-inducing factors, both in vitro and in vivo. Our aim was to determine the factors and potential therapeutic targets that regulate CD8alpha+ DC migration. Herein we have employed an in vitro chemotaxis assay for the determination of which, if any, CC chemokines specifically regulate the migration of CD8alpha+ (and CD8alpha-) murine spleen DC. We also used this assay with the addition of endothelial cell layers, to assess the adhesion molecules that facilitate DC transendothelial migration. Two chemokines (CCL19 and CCL21) elicited CD54-dependent migration of both mature DC subsets, in the presence or absence of endothelial cells, but CD8alpha+ DC migrated in consistently fewer numbers than CD8alpha- DC in vitro. Our findings led us to investigate the importance of the in vitro migration-inducing chemokines in vivo. In these studies we compared the ability of DC subsets to migrate to T cell areas of wild type and specific chemokine-deficient mice. Unlike our in vitro results, the DC subsets migrated with equal efficiency in normal recipients. After sc injection into CCL19/CC21-deficient mice, CD8alpha- DC trafficked more efficiently than CD8alpha+ DC to draining lymphoid tissue. The necessity of specific chemokine-directed DC migration in vivo for alloimmune responses was borne out in transplant studies in which impaired migration of DC resulted in significant prolongation of murine cardiac allograft survival. These studies demonstrate, for the first time, potential chemokine and adhesion molecule targets for manipulation of murine DC subset migration in vivo.
Advisor:Angus W Thomson; Walter Storkus; Chau-Ching Liu; Louis D Falo; Simon Barratt-Boyes
School:University of Pittsburgh
School Location:USA - Pennsylvania
Source Type:Master's Thesis
Date of Publication:04/20/2004