Journal of Dental Research, Vol 70, 107-110, Copyright © 1991 by International & American Associations for Dental Research Online Journals
Activation of complement by Treponema denticola
H. A. Schenkein and C. R. Berry
Virginia Commonwealth University, School of Dentistry, Richmond 23298.
Oral spirochetes have been shown to be associated with periodontal diseases
and are present in increased numbers in lesions of greater severity. In
this study, the interaction of Treponema denticola with human complement, a
major antibacterial defense system, was examined. For each of two strains
of T. denticola, it was found that both the classical and alternative
pathways of human complement were activated in human serum upon incubation
at 37 degrees C. C3 fragments were deposited on the surface of this
organism following complement activation; the fragments bound included both
of the major C3-derived opsonic fragments C3b and iC3b. Under incubation
conditions identical to those carried out for complement activation in
serum, T. denticola failed to degrade purified, hemolytically-active C3,
although it readily degraded inactivated C3. Thus, despite the documented
proteolytic activity of this organism, complement activation and deposition
of complement-derived opsonins may be important defense mechanisms in the
control of infections with T. denticola.
