title: Recombinant Mycobacterium leprae protein associated with entry into mammalian cells of respiratory and skin components.
abstract: BACKGROUND
  The transmission of Mycobacterium leprae, the causative pathogen of leprosy, has been postulated to occur mainly through upper respiratory route rather than skin-to-skin contact via minor injuries. The M. leprae genome contains mce1A gene, which encodes a putative mammalian cell entry protein. However, to date, there have been no functional analyses of the M. leprae mce1A gene product.
  
  
  OBJECTIVE
  The aim of this study was to elucidate a possible relationship between this transmission mechanism and the mce1A gene product.
  
  
  METHODS
  We analyzed the cell uptake activity in vitro of polystyrene latex beads coated with a purified recombinant (r-) protein expressed by a 849-bp locus within the mce1A gene.
  
  
  RESULTS
  The r-protein promoted uptake of the beads into human nasal epithelial cells derived from nasal polyps, human bronchial epithelial cell line, normal human dermal fibroblasts, normal human microvascular endothelial cells and normal human keratinocytes cultured at 0.01 mM extracellular calcium concentration [Ca]; no uptake occurred with keratinocytes cultured at 1.2mM [Ca].
  
  
  CONCLUSIONS
  These results suggest that the mce1A gene product can mediate M. leprae entry into respiratory epithelial cells as their natural target cells, which may be the main mode of transmission. Endothelial cells, on the other hand, may serve as the reservoir of the bacilli for long-term infection. The M. leprae Mce1A protein has potential important implications for mode of transmission and pathogenesis of leprosy.
authors.affiliation: Department of Dermatology, Graduate School of Medical Science, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Sato
authors.forename: Takao
authors.initials: T
authors.lastname: Fujimura
authors.forename: Mikio
authors.initials: M
authors.lastname: Masuzawa
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Yogi
authors.forename: Masanori
authors.initials: M
authors.lastname: Matsuoka
authors.forename: Maho
authors.initials: M
authors.lastname: Kanoh
authors.forename: Lee W
authors.initials: LW
authors.lastname: Riley
authors.forename: Kensei
authors.initials: K
authors.lastname: Katsuoka
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D004847:Epithelial Cells / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D015603:Keratinocytes / Q000378:metabolism; D007918:Leprosy / Q000378:metabolism / Q000635:transmission*; D009166:Mycobacterium leprae / Q000378:metabolism / Q000472:pathogenicity*; D009297:Nasal Mucosa / Q000166:cytology / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D020545:Respiratory Mucosa / Q000166:cytology / Q000378:metabolism*; D012867:Skin / Q000166:cytology / Q000378:metabolism*
chemical_list: D001426:Bacterial Proteins; C520228:Mce1A protein, Mycobacterium leprae; D011994:Recombinant Proteins; D002118:Calcium