title: Mediator responses of alveolar macrophages and kinetics of mononuclear phagocyte subset recruitment during acute primary and secondary mycobacterial infections in the lungs of mice.
abstract: Little is known about the activation programme induced in alveolar macrophages upon phagocytosis of mycobacteria and the concomitant mononuclear phagocyte migratory responses that shape the acute phase of mycobacterial infection. Using high-speed cell sorting in conjunction with real-time RT-PCR analysis, we show that sorted alveolar macrophages of transgenic CX3CR1+/GFP mice infected with red fluorescent-labelled Mycobacterium bovis BCG exhibited weak transcriptional changes of lysosomal cathepsins B, L, D, K and S, whereas antimicrobial cathepsin G was strongly induced upon infection. Moreover, mRNA levels of pattern recognition receptors TLR2, TLR4 and NOD2 were downregulated as were neutrophil chemoattractants KC, MIP-2 and IP-10, whereas highly upregulated mRNA levels of the monocyte chemoattractant CCL2 were observed. M. bovis BCG infection of the mice elicited the alveolar accumulation of highly CX3CR1-positive alveolar dendritic cells but not neutrophils within the alveolar compartment, whereas no increased accumulation of CX3CR1high lung parenchymal dendritic cells (lung DC) or CX3CR1neg lung macrophages compared with controls was noted. In contrast, CX3CR1+/GFP mice previously immunized with M. bovis BCG rapidly responded with increased accumulations of both CX3CR1high alveolar and lung parenchymal DC and CX3CR1neg lung macrophages upon intratracheal M. bovis BCG challenge. Moreover, alveolar and lung macrophages and lung DC were found to contribute to early uptake of M. bovis BCG. Together, acute mycobacterial infection triggers both rapid changes in gene expression profiles in infected alveolar macrophages and a compartment-specific accumulation of mononuclear phagocyte subsets contributing to M. bovis BCG uptake in vivo.
authors.affiliation: Laboratory for Experimental Lung Research, Department of Pulmonary Medicine, Hannover School of Medicine, Hannover, Germany.
authors.forename: Mrigank
authors.initials: M
authors.lastname: Srivastava
authors.forename: Antje
authors.initials: A
authors.lastname: Meinders
authors.forename: Kathrin
authors.initials: K
authors.lastname: Steinwede
authors.forename: Regina
authors.initials: R
authors.lastname: Maus
authors.forename: Nadine
authors.initials: N
authors.lastname: Lucke
authors.forename: Frank
authors.initials: F
authors.lastname: Bühling
authors.forename: Stefan
authors.initials: S
authors.lastname: Ehlers
authors.forename: Tobias
authors.initials: T
authors.lastname: Welte
authors.forename: Ulrich A
authors.initials: UA
authors.lastname: Maus
mesh_terms: D000818:Animals; D000073883:CX3C Chemokine Receptor 1; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008168:Lung / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D016676:Macrophages, Alveolar / Q000378:metabolism* / Q000382:microbiology / Q000473:pathology; D051379:Mice; D008807:Mice, Inbred BALB C; D008822:Mice, Transgenic; D008856:Microscopy, Fluorescence; D009000:Monocytes / Q000378:metabolism / Q000382:microbiology / Q000473:pathology; D009163:Mycobacterium bovis / Q000254:growth & development*; D053473:Nod2 Signaling Adaptor Protein / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019707:Receptors, Chemokine / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051195:Toll-Like Receptor 2 / Q000235:genetics / Q000378:metabolism; D051197:Toll-Like Receptor 4 / Q000235:genetics / Q000378:metabolism; D014397:Tuberculosis, Pulmonary / Q000235:genetics* / Q000378:metabolism / Q000382:microbiology
chemical_list: D000073883:CX3C Chemokine Receptor 1; C471885:Cx3cr1 protein, mouse; D053473:Nod2 Signaling Adaptor Protein; C495945:Nod2 protein, mouse; D012333:RNA, Messenger; D019707:Receptors, Chemokine; C493486:Tlr2 protein, mouse; C493487:Tlr4 protein, mouse; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D049452:Green Fluorescent Proteins