The Journal of Medical Microbiology, Vol 16, Issue 3 281-293, Copyright © 1983 by Society for General Microbiology
Effect of serum concentration and metabolic inhibitors on the attachment of Treponema pallidum to rabbit cells
G. H. Wong, B. Steiner, S. Faine and S. Graves
The effect of host-cell metabolism on the attachment of Treponema pallidum
to mammalian cells in vitro was studied. The growth of baby rabbit genital
organ (BRGO) cells was enhanced by increasing the concentration of serum
("serum shift-up") in the growth medium. Cells starved for 24 h in
serum-free medium showed a burst of DNA synthesis when shifted to fresh
medium containing 20% serum. In aerobic conditions, they were much more
heavily coated with attached T. pallidum than cells shifted to 20% serum
after maintenance at serum concentrations of 2.5%, 5% or 10%. This effect
was very pronounced during the first few hours of co-incubation. In
microaerophilic conditions, the extent of T. pallidum adherence also
paralleled the increase in DNA synthesis by BRGO cells. Cycloheximide and
methotrexate greatly inhibited DNA and protein synthesis in BRGO cells, but
did not affect the motility of T. pallidum. When BRGO cell metabolism was
inhibited by these two drugs, attachment of T. pallidum was significantly
decreased. These results indicate that T. pallidum attaches best to
actively growing BRGO cells in tissue culture. This may explain the
apparently preferential parasitism of actively growing tissues by T.
pallidum in syphilis in man.
