Cellular adhesion molecules on periodontal lymphocytes.

T cell induced differentiation of B cells has been shown to be dependent on the CD2/LFA-3 and LFA-1/ICAM-1 pathways. Flow cytometric analysis was used to examine these adhesion molecules on T and B cells extracted from gingival tissues before and after stimulation with the putative periodontopathic bacteria, Porphyromonas gingivalis and Fusobacterium nucleatum. Adhesion molecule expression on peripheral blood cells from healthy adults was used as a control. Approximately 50 per cent of B cells extracted from gingival tissues expressed LFA-3 and ICAM-1 compared with 30 per cent positive peripheral blood B cells. Around 50 per cent of gingival T cells expressed CD2 relative to 76 per cent positive peripheral blood T cells. However, 40-50 per cent of both gingival and peripheral blood T cells expressed LFA-1. There was no difference in the expression of adhesion molecules on T and B cells extracted from health/marginal gingivitis or adult periodontitis lesions. After stimulation of gingival cells in vitro, the per cent CD2 positive T cells and LFA-3 and ICAM-1 positive B cells remained relatively stable over the six-day culture period, although P. gingivalis and F. nucleatum appeared to induce an increase in the percentage of gingival T cells expressing LFA-1. In contrast to the gingival lymphocytes, stimulation of peripheral blood cells resulted in an increase in the per cent CD2 positive T cells, LFA-3 and ICAM-1 positive B cells, with a decrease in LFA-1 positive T cells. The results therefore demonstrated that gingival T and B cells express adhesion molecules in vivo.(ABSTRACT TRUNCATED AT 250 WORDS)