02549nas a2200385   4500000000100000008004100001260001300042653002300055653001200078653002200090653002100112653001600133653001500149653001100164653001800175653001200193653002500205653001700230653002500247653002300272653000900295100001100304700001500315700001500330700001100345700001500356700001200371700001200383700001500395245012400410300001100534490000700545520159700552022001402149       2007                            d  c2007 May10aBacterial Proteins10aCalcium10aEndothelial Cells10aEpithelial Cells10aFibroblasts10aHela Cells10aHumans10aKeratinocytes10aleprosy10aMycobacterium leprae10aNasal Mucosa10aRecombinant Proteins10aRespiratory Mucosa10aSkin1 aSato N1 aFujimura T1 aMasuzawa M1 aYogi Y1 aMatsuoka M1 aKanoh M1 aRiley L1 aKatsuoka K00aRecombinant Mycobacterium leprae protein associated with entry into mammalian cells of respiratory and skin components.  a101-100 v463 a<p><b>BACKGROUND: </b>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.</p><p><b>OBJECTIVE: </b>The aim of this study was to elucidate a possible relationship between this transmission mechanism and the mce1A gene product.</p><p><b>METHODS: </b>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.</p><p><b>RESULTS: </b>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].</p><p><b>CONCLUSION: </b>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.</p>  a0923-1811