title: Interactions between an M. tuberculosis strain overexpressing mtrA and mononuclear phagocytes.
abstract: OBJECTIVE
  It was previously shown that the bacterial two-component regulatory signal transduction (2CR) system MtrAB may be associated with the ability of M. tuberculosis (Mtb) to survive in macrophages. In the present work Mtb mutants: Rv-78 with overexpression of mtrA and Rv-129 with elevated level of phosphorylation-defective MtrA were used for further investigation of the potential influence of the MtrAB system on Mtb interaction with human monocytes.
  
  
  METHODS
  Flow cytometry was used to determine the expression of MHC class II molecules. The expression of genes for inducible nitric oxide synthase (iNOS) and cathepsin G was quantified by RT-PCR. The association of Mtb strains with Rab5 and Rab7 positive vacuoles was investigated applying confocal microscopy. IL-10 and IL-12 secretion by monocytes as well as the Mtb susceptibility to cathepsin G were investigated.
  
  
  RESULTS
  Mutation-carried and wild type Mtb strains inhibited MHC class II expression on monocytes to a similar extent. Monocyte stimulation with mycobacteria led to the increased production of IL-10 but no detectable amounts of IL-12 or NO were observed. Expression of the gene for iNOS was not detected while that for cathepsin G was shown, however its intensity was not associated with MtrA mutation. Mtb mutant strains were more effectively enclosed in phagosomes containing the late endosome marker Rab7 as compared to the control.
  
  
  CONCLUSIONS
  The results may confirm the importance of the MtrAB system in mycobacterial capacity for successful survival in phagocytes, especially in the context of high degree of colocalization of Mtb Rv-78 to mature phagosomes.
authors: Department of Immunology and Infectious Biology, University of Lodz, Lodz, Poland. marekfol@poczta.onet.pl
authors: M
authors: M
authors: Fol
authors: L
authors: L
authors: Iwan-Barańska
authors: P
authors: P
authors: Stączek
authors: M
authors: M
authors: Krupiński
authors: S
authors: S
authors: Różalska
authors: M
authors: M
authors: Kowalewicz-Kulbat
authors: M
authors: M
authors: Druszczyńska
authors: M V V S
authors: MV
authors: Madiraju
authors: D
authors: D
authors: Kaczmarczyk
authors: W
authors: W
authors: Rudnicka
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics*; D000900:Anti-Bacterial Agents / Q000737:chemistry; D001426:Bacterial Proteins / Q000235:genetics*; D056649:Cathepsin G / Q000378:metabolism; D016207:Cytokines / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D016753:Interleukin-10 / Q000378:metabolism; D018664:Interleukin-12 / Q000378:metabolism; D008264:Macrophages / Q000378:metabolism; D018613:Microscopy, Confocal; D009000:Monocytes / Q000166:cytology / Q000382:microbiology*; D009154:Mutation; D009169:Mycobacterium tuberculosis / Q000235:genetics* / Q000254:growth & development; D009569:Nitric Oxide / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D010766:Phosphorylation; D016601:RNA-Binding Proteins / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D015398:Signal Transduction; D014157:Transcription Factors / Q000235:genetics
chemical_list: D018528:ATP-Binding Cassette Transporters; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D016207:Cytokines; C100938:MtrA protein, Bacteria; C079092:MtrB protein, Bacteria; D016601:RNA-Binding Proteins; D014157:Transcription Factors; D016753:Interleukin-10; D018664:Interleukin-12; D009569:Nitric Oxide; C496319:NOS2 protein, human; D052247:Nitric Oxide Synthase Type II; D056649:Cathepsin G