CD11b expression on neutrophils in human crevicular fluid collected from clinically healthy gingivae

This study investigated the cell surface expression of CD11b (Mo 1, Mac-1, CR 3) by neutrophils (PMNs) from human crevicular fluid (CF-PMNs). CD11b expression on CF-PMNs was compared, using flow cytometry, to that on peripheral blood PMNs (PB-PMNs) isolated simultaneously from the same subjects. CD11b expression by CF-PMNs was also compared to that on PB-PMNs stimulated with formylmethionylleucylphenylalanine (fMLP) or crevicular fluid supernatant (cell-free portion of CF diluted with buffer) (CFS). Crevicular PMNs consistently expressed more CD11b than unstimulated PB-PMNs (p less than 0.001). The level of CD11b expressed on these CF-PMNs was significantly greater than that expressed by PB-PMNs stimulated with 10(-8) M fMLP (p less than 0.05). The level of CD11b surface expression on CF-PMNs was not statistically different from that expressed on PB-PMNs stimulated with CFS or 10(-6) M fMLP. However, CFS significantly stimulated upregulation of surface CD11b expression on PB-PMNs relative to that achieved with 10(-8) M fMLP (0.01 less than p less than or equal to 0.025). Thus it is concluded that CF-PMNs express a high level of CD11b and CFS can upregulate CD11b expression on PB-PMNs to a level that is at least as great as that achieved with 10(-8) M fMLP.