Blastogenic responsiveness of human lymphoid cells to mitogens and to homogenates of periodontal pocket bacteria

Experiments aimed at demonstrating significant differences in the blastogenic responsiveness of peripheral blood mononuclear cells (PBM) activated using bacterial preparations and pokeweed mitogen (PWM) were performed. The known variables in the in vitro assay system were controlled to the greatest extent possible. A range of cell and activator concentrations, incubation times extending from 3 to 7 days, conical microtest wells, and a labeling procedure which accurately reflects blastogenesis was used. Under these test conditions, cultures of activated patient cells did not differ significantly from activated control cells in counts incorporated, in Stimulation Index, or in incubation time, cell concentration, or activator dose required for maximal blastogenesis, except for cultures activated with LPS and PWM. Responsiveness of cultures of patient cells activated with LPS was significantly lower than that of cultures of control cells (P < 0.01). Cultures from most normal control donors exposed to PWM became maximally activated at 3 days' incubation, while cultures from most patients required 5 to 7 days. Cultures of patient cells did differ significantly (p < 0.05) from control cells in that their spontaneous lymphocyte proliferation was suppressed. These observations indicate that patients with periodontitis may have abnormalities in basic immunologic control mechanisms.