title: Lymphocyte response to T-cell mitogen during experimental gingivitis in humans.
abstract: This study was conducted to evaluate the dose response relationships of peripheral blood lymphocytes (PBL) by stimulation of phytohemagglutinin (PHA) during the onset of oral inflammation. Eleven dental students underwent a 3-week experimental gingivitis program (Löe et al., 1965). At time zero, weeks 1, 2, and 3, and after 1 week of reinstituted oral hygiene (week 4), the plaque accumulations were evaluated, the degree of gingival inflammation was assessed, and a blood sample was taken. Quadruplicate microcultures each containing 2 x 10(5) PBL in 0.2 ml of tissue culture medium 199 and 10% fetal calf serum were stimulated with five concentrations of PHA (10 to 0.5 mug/ml) and incubated for 78 h at 37 C in 5% CO2. [3H]thymidine was added to each culture for the final 8 h. The cultures were then harvested and counted by liquid scintillation, and stimulation indexes (SI) were determined. At time zero the maximum PBL response occurred at a PHA concentration of 5 mug/ml (SI = 100). During weeks 1, 2, and 3 the location of the maximum PBL response shifted to a lower PHA concentration (1.0 mug/ml) and increased to over SI =400. The phenomenon of shifting peak PHA responses to lower PHA concentrations could be observed after only 1 week of developing gingival inflammation. The PBL response returned to pre-experimental values after 1 week of reinstituted oral hygiene, which resolved the oral inflammation. The findings show that a dose response relationship exists between PHA concentrations and the PBL response. If these dose response changes seen during developing gingival inflammation are ignored, either a decrease, increase, or no change in PBL response can be shown depending upon the PHA concentration evaluated. Owing to the dose-dependent nature of this PBL response, it is advisable to routinely use dose response curves in order to properly evaluate the full responsiveness of PBL to mitogenic substances.
mesh_terms: D000328:Adult; D003773:Dental Plaque / Q000175:diagnosis; D004305:Dose-Response Relationship, Drug; D005891:Gingivitis / Q000276:immunology*; D006801:Humans; D008213:Lymphocyte Activation / Q000187:drug effects*; D008934:Mitogens / Q000494:pharmacology*; D013601:T-Lymphocytes
chemical_list: D008934:Mitogens