title: Programmed death ligand-1 expression and memory T-cell generation in Coxiella burnetii infection.
abstract: Programmed death ligand-1 (PD-L1) is a co-signaling molecule that regulates T-cell responses in vivo. Its role in bacterial infections, including Q fever, a zoonosis due to Coxiella burnetii infection, is not well understood. We showed by flow cytometry that PD-L1 membrane expression was specifically increased in T-cells from patients with acute Q fever, not from patients with Q fever endocarditis, suggesting that PD-L1 plays a role in the early phases of C. burnetii infection. To assess this hypothesis, we studied the role of PD-L1 in C. burnetii-infected mice. C. burnetii infection resulted in PD-L1 up-regulation in splenocytes. Anti-PD-L1 antibodies injected into the mice did not affect the total number of splenic T-cells but increased the relative number of CD4(+) T-cells compared with CD8(+) T-cells. Additionally, anti-PD-L1 antibodies significantly increased the number of splenic CD4(+) and CD8(+) T cells that expressed low membrane CD62L levels. Our results indicate that the increased expression of PD-L1 by T-cells is associated with a decreased number of memory T-cells during C. burnetii infection, opening new perspectives in the understanding of Q fever pathophysiology.
authors: Aix-Marseille University, Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, UMR 63, CNRS 7278, IRD 198, INSERM U1095, Marseille, France; Inserm UMR 1068, Centre de Recherche en Cancérologie de Marseille, Marseille, France.
authors: Mignane B
authors: MB
authors: Ka
authors: Aix-Marseille University, Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, UMR 63, CNRS 7278, IRD 198, INSERM U1095, Marseille, France.
authors: Yassina
authors: Y
authors: Bechah
authors: Inserm UMR 1068, Centre de Recherche en Cancérologie de Marseille, Marseille, France.
authors: Daniel
authors: D
authors: Olive
authors: Aix-Marseille University, Unité de Recherche sur les Maladies Infectieuses Transmissibles et Emergentes, UMR 63, CNRS 7278, IRD 198, INSERM U1095, Marseille, France. Electronic address: jean-louis.mege@univ-amu.fr.
authors: Jean-Louis
authors: JL
authors: Mege
mesh_terms: D000818:Animals; D060890:B7-H1 Antigen / Q000032:analysis*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D007156:Immunologic Memory; D016130:Immunophenotyping; D019041:L-Selectin / Q000032:analysis; D018655:Lymphocyte Count; D008810:Mice, Inbred C57BL; D011778:Q Fever / Q000276:immunology*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D015854:Up-Regulation
chemical_list: D060890:B7-H1 Antigen; C423236:CD274 protein, human; D019041:L-Selectin
keywords: CD62L; Coxiella burnetii; PD-L1; T-cells