Microbe-induced lymphocyte blastogenesis enhancement after preculture.

The in vitro blastogenic response of human peripheral blood mononuclear cells to Fusobacterium nucleatum and other oral microorganisms was enhanced if the peripheral blood mononuclear cells were cultured for 24 h at 37 degrees C prior to the addition of stimulant. The enhancement which occurred at optimal and supraoptimal concentrations of F. nucleatum (10 to 100 micrograms/ml) was detected after a preculture period of as little as 2 h. The blastogenic response was a result of T-cell proliferation, and enhancement occurred independently of monocytes. Suppressor activity was induced by culturing fresh lymphocytes for 24 h in the presence of supraoptimal concentrations of F. nucleatum. The enhancement phenomenon occurred independently of the prostaglandin effects on lymphocyte blastogenesis and was not abrogated by treatment with indomethacin.