The lymphoproliferative response during human experimental gingivitis

Abstract

The lymphocyte blastogenic responses to antigen preparations of bacteria from dental microbial plaque and to other non‐oral stimulants were longitudinally assayed in eitht adult subjects using the experimental gingivitis model. During the 28 days of the experimental period, these subjects abstained from all oral hygiene procedures which let to accumulatio of increased amounts of microbial dental plaque and subsequent gingivitis. In general, all subjects demonstrated a significant increase in the lymphoproliferative response to all doses of phytohemagglutinin (PHA) during the experimental period. The subjects were divided into 2 groups based on rate of plaque accumulation. Slow plaque formers exhibited a gradual linear increase in blastogenic response to bacterial antigen preparations throughout the experimental period. In the group characterixed by rapid accumulation of plaque, a marked early increase in blastogenic responses to antigens of Actinomyces viscosus, Actinomyces naeslundii, Bacteroides melaninogenicus, and Treponema denticola was observed. These same subjects, however, demonstrated a reduction in lymphocyte response to the above antigens during the later phase of the experimental period, when gingivitis was most severe. This decrease, in light of the similtaneous increase in PHA response, suggests the existence of a homeostatic mechanism to control the immune response during episodes of increased antigen load.