期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1999
卷号：96
期号：17
页码：9857-9862
DOI：10.1073/pnas.96.17.9857
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Nerve damage is the hallmark of Mycobacterium leprae infection, which results from M. leprae invasion of the Schwann cell of the peripheral nervous system. We have recently shown that the laminin-2 isoform, specially the G domain of laminin 2 chain, on the Schwann cell-axon unit serves as an initial neural target for M. leprae. However, M. leprae surface molecules that mediate bacterial invasion of peripheral nerves are entirely unknown. By using human 2 laminins as a probe, a major 28-kDa protein in the M. leprae cell wall fraction that binds 2 laminins was identified. After N-terminal amino acid sequence analysis, PCR-based strategy was used to clone the gene that encodes this protein. Deduced amino acid sequence of this M. leprae laminin-binding protein predicts a 21-kDa molecule (ML-LBP21), which is smaller than the observed molecular size in SDS/PAGE. Immunofluorescence and immunoelectron microscopy on intact M. leprae with mAbs against recombinant (r) ML-LBP21 revealed that the protein is surface exposed. rML-LBP21 avidly bound to 2 laminins, the rG domain of the laminin-2 chain, and the native peripheral nerve laminin-2. The role of ML-LBP21 in Schwann cell adhesion and invasion was investigated by using fluorescent polystyrene beads coated with rML-LBP21. Although beads coated with rML-LBP21 alone specifically adhered to and were ingested by primary Schwann cells, these functions were significantly enhanced when beads were preincubated with exogenous 2 laminins. Taken together, the present data suggest that ML-LBP21 may function as a critical surface adhesin that facilitates the entry of M. leprae into Schwann cells.
