Advances in Dental Research, Vol 8, 254-262, Copyright © 1994 by International & American Associations for Dental Research
Bacterial-protein interactions in the oral cavity
C. W. Douglas
Department of Oral Pathology, School of Clinical Dentistry, University of Sheffield, UK.
Bacteria in the oral cavity must interact with salivary proteins if they
are to survive. Such interactions can take several forms, either providing
nutrients, a means of adhesion to surfaces, or resulting in aggregation or
killing and, therefore, clearance of organisms. Recent work has provided an
insight into the mechanisms of some of these bacterial-protein
interactions, revealing complexity and diversity. For example, the
interaction between a putative Streptococcus mutans adhesin, P1 (B, I/II,
etc.), and a parotid glycoprotein results in adhesion when it occurs at a
surface or aggregation when in solution, and different domains of P1 appear
to be involved in the two processes. An alternative strategy is employed by
Actinomyces viscosus, which interacts, via its type-1 fimbriae, with a
proline-rich salivary protein; however, this interaction occurs only when
the PRP is adsorbed to a surface. A. viscosus takes advantage of a
conformational change in the PRP when it becomes surface-bound, which
exposes a cryptic part of the molecule. A third, and intriguing, type of
interaction is seen between various streptococci and salivary amylase. This
does not result in either adherence or aggregation but provides organisms
with the ability to utilize starch breakdown products for metabolism. An
understanding of the mechanisms involved in bacterial-protein interactions
could conceivably lead to novel methods for controlling specific pathogens,
but the systems operating in the mouth are numerous, complex, and diverse.
