title: Loss of dendritic cell migration and impaired resistance to Leishmania donovani infection in mice deficient in CCL19 and CCL21.
abstract: The encounter between APC and T cells is crucial for initiating immune responses to infectious microorganisms. In the spleen, interaction between dendritic cells (DC) and T cells occurs in the periarteriolar lymphoid sheath (PALS) into which DC and T cells migrate from the marginal zone (MZ) along chemokine gradients. However, the importance of DC migration from the MZ into the PALS for immune responses and host resistance to microbial infection has not yet been elucidated. In this study, we report that following Leishmania donovani infection of mice, the migration of splenic DC is regulated by the CCR7 ligands CCL19/CCL21. DC in plt/plt mutant mice that lack these chemokines are less activated and produce less IL-12, compared with those in wild-type mice. Similar findings are seen when mice are treated with pertussis toxin, which blocks chemokine signaling in vivo. plt/plt mice had increased susceptibility to L. donovani infection compared with wild-type mice, as determined by spleen and liver parasite burden. Analysis of splenic cytokine profiles at day 14 postinfection demonstrated that IFN-gamma and IL-4 mRNA accumulation was comparable in wild-type and plt/plt mice. In contrast, accumulation of mRNA for IL-10 was elevated in plt/plt mice. In addition, plt/plt mice mounted a delayed hepatic granulomatous response and fewer effector T cells migrated into the liver. Taken together, we conclude that DC migration from the MZ to the PALS is necessary for full activation of DC and the optimal induction of protective immunity against L. donovani.
authors.affiliation: Department of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom.
authors.forename: Manabu
authors.initials: M
authors.lastname: Ato
authors.forename: Asher
authors.initials: A
authors.lastname: Maroof
authors.forename: Soombul
authors.initials: S
authors.lastname: Zubairi
authors.forename: Hideki
authors.initials: H
authors.lastname: Nakano
authors.forename: Terutaka
authors.initials: T
authors.lastname: Kakiuchi
authors.forename: Paul M
authors.initials: PM
authors.lastname: Kaye
mesh_terms: D000818:Animals; D002465:Cell Movement; D002478:Cells, Cultured; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D019742:Chemokines, CC / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D003713:Dendritic Cells / Q000166:cytology* / Q000378:metabolism*; D005786:Gene Expression Regulation; D018664:Interleukin-12 / Q000378:metabolism; D007893:Leishmania donovani / Q000502:physiology*; D007896:Leishmaniasis / Q000276:immunology / Q000378:metabolism* / Q000469:parasitology / Q000473:pathology*; D008264:Macrophages / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013154:Spleen / Q000469:parasitology / Q000473:pathology; D013997:Time Factors
chemical_list: C515461:Ccl19 protein, mouse; C515479:Ccl21c protein, mouse; D054415:Chemokine CCL19; D054421:Chemokine CCL21; D019742:Chemokines, CC; D018664:Interleukin-12