Recombinant Mycobacterium leprae protein associated with entry into mammalian cells of respiratory and skin components.
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.
Sato
Naoya
N
Department of Dermatology, Graduate School of Medical Science, Kitasato University, 1-15-1 Kitasato, Sagamihara, Kanagawa 228-8555, Japan.
Fujimura
Takao
T
Masuzawa
Mikio
M
Yogi
Yasuko
Y
Matsuoka
Masanori
M
Kanoh
Maho
M
Riley
Lee W
LW
Katsuoka
Kensei
K
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*
D001426:Bacterial Proteins; C520228:Mce1A protein, Mycobacterium leprae; D011994:Recombinant Proteins; D002118:Calcium