Internalization of Mycobacterium bovis Bacillus Calmette-Guérin into osteoblast-like MC3T3-E1 cells and bone resorptive responses of the cells against the infection.
Mycobacterium bovis BCG (BCG) is a live vaccine used worldwide against tuberculosis. However, it has unfavourable side effects such as osteitis or osteomyelitis, and these sometimes lead to vertebral caries in some patients as a result of bone resorption. Osteoblasts might play a role in the bone resorption caused by BCG infection, because they are central cells in bone metabolism. Cultured osteoblast-like cell lines (MC3T3-E1) derived from C57BL mice susceptible to BCG infection cells were infected with BCG at several doses. Interestingly, internalization of BCG-enveloped phagosome-like membrane in osteoblast-like cells were observed by transmission electron microscopy (TEM). Owing to infection, the proliferation and alkaline phosphatase activity of the osteoblast-like cells were reduced in a dose-dependent manner. On the other hand, interleukin (IL)-6 production was considerably enhanced by infection. These results suggest that BCG infects osteoblasts, suppressing their proliferation and differentiation and inducing bone resorption, which may be related to osteitis/osteomyelitis and bone caries caused by BCG infection.
Hotokezaka
H
H
Department of Orthodontics, Nagasaki University School of Dentistry, Sakamoto, Japan.
Kitamura
A
A
Matsumoto
S
S
Hanazawa
S
S
Amano
S
S
Yamada
T
T
D000818:Animals; D001862:Bone Resorption / Q000209:etiology* / Q000378:metabolism / Q000382:microbiology*; D002454:Cell Differentiation; D002455:Cell Division; D002460:Cell Line; D015850:Interleukin-6 / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D009163:Mycobacterium bovis; D010006:Osteoblasts / Q000166:cytology / Q000382:microbiology* / Q000502:physiology*; D014376:Tuberculosis / Q000150:complications* / Q000662:veterinary*
D015850:Interleukin-6