title: Role of the programmed Death-1 pathway in the suppressive activity of alternatively activated macrophages in experimental cysticercosis.
abstract: We characterised a population of macrophages potentially involved in the immunoregulation induced by experimental cysticercosis. Following Taenia crassiceps infection, macrophages recruited in the peritoneal cavity were isolated and co-cultured at different ratios with T cells from naïve mice previously stimulated with anti-CD3/CD28 antibodies; these macrophages inhibited naïve T cell proliferation. This suppressive effect was Interleukin (IL)-10, Interferon-gamma (IFN-gamma), and nitric oxide (NO) independent. In contrast, macrophage-T cell contact was necessary to maintain anergy of T cells. Reverse transcriptase-PCR analysis of these macrophages showed higher transcripts of IL-10, chitinases Fizz1 and Ym1, and arginase-1 compared with naïve macrophages; by contrast, IL-12p40, and inducible nitric oxide synthase (iNOS) transcripts were undetected, whereas C-C chemokine ligand 5 (CCL5) was unchanged. Analysis of the membrane molecules expressed on Taenia-induced macrophages showed an up-regulation of several markers, mainly programmed death ligand 1 (PD-L1) and PD-L2. Blockade of PD-L1, PD-L2 or their receptor PD-1, but not of another marker, eliminated their ability to inhibit T-cell proliferation. Parallel experiments using ovalbumin (OVA)-peptide as a model antigen displayed similar results. Additionally, the same mechanism appears to be functional in splenocytes of T. crassiceps-infected mice given that blockade of PD-1, PD-L1 or PD-L2 re-established their ability to proliferate in response to parasite antigens. Moreover, Taenia-induced macrophages were able to suppress a mixed lymphocyte reaction in a PD-1-dependent manner. Thus, cestode infections induce macrophages alternatively activated with strong suppressive activity involving the PD-1/PD-L's pathway.
authors.affiliation: Facultad de Estudios Superiores Iztacala, Laboratory of Immunoparasitology, Unidad de Biomedicina, Universidad Nacional Autónoma de México, Av. De los Barrios #1, Los Reyes Iztacala, Edo. de México, Mexico. literrazas@campus.iztacala.unam.mx
authors.forename: Luis I
authors.initials: LI
authors.lastname: Terrazas
authors.forename: Daniel
authors.initials: D
authors.lastname: Montero
authors.forename: César A
authors.initials: CA
authors.lastname: Terrazas
authors.forename: José L
authors.initials: JL
authors.lastname: Reyes
authors.forename: Miriam
authors.initials: M
authors.lastname: Rodríguez-Sosa
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000276:immunology; D018122:B7-1 Antigen / Q000276:immunology*; D060890:B7-H1 Antigen; D049109:Cell Proliferation; D017635:Clonal Anergy / Q000276:immunology*; D018920:Coculture Techniques; D003551:Cysticercosis / Q000276:immunology*; D005260:Female; D005434:Flow Cytometry; D008213:Lymphocyte Activation / Q000276:immunology; D007959:Lymphocyte Culture Test, Mixed; D008262:Macrophage Activation / Q000276:immunology*; D017737:Macrophages, Peritoneal / Q000276:immunology*; D008562:Membrane Glycoproteins / Q000276:immunology*; D008565:Membrane Proteins / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D010455:Peptides / Q000276:immunology*; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D015398:Signal Transduction / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology
chemical_list: D051017:Apoptosis Regulatory Proteins; D018122:B7-1 Antigen; D060890:B7-H1 Antigen; C498919:Cd274 protein, mouse; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C484279:Pdcd2 protein, mouse; D010455:Peptides