Variation in Memory T Cells Following Periodontal Treatment

Abstract

T cells are a major cell subset of the adaptive immune system that play a central role in periodontitis. One distinguishing feature of adaptive immunity is immunological memory. Memory refers to the ability of the immune system to respond more rapidly and efficiently to a specific pathogen that has been encountered previously. Memory T cells can be divided into four subsets based on surface expression of CD45RA and CCR7 expression where TN cells are CCR7+CD45RA+, effector memory T cells which re-express CD45RA (TEMRA) are CCR7-CD45RA+, central memory T cells (TCM) are CCR7+CD45RA-, effector memory T cells (TEM) are CCR7-CD45RA-. Periodontal parameters and peripheral blood mononuclear cells were collected from 54 periodontitis patients at baseline, 3-, 6- and 12-months post-therapy and 40 healthy controls. TN, TCM, TEM and TEMRA cells were identified using flow cytometry in CD4+, CD8+, CD4+CD8+ and CD4-CD8- T-cells At baseline, periodontitis subjects had significantly lower TN but higher CD4+ TCM, CD8+ TCM, CD4+CD8+ TEM, and CD4-CD8- TEM cell proportions compared to health. Periodontal therapy decreased TEM and CD4+ and CD8+ TCM cells, but increased TN and CD4+ and CD8+ TEMRA cells. Thus, periodontal management modifies peripheral memory T-cell profile in periodontitis.