Kinetics of CD11b expression on neutrophils isolated from subjects with healthy gingivae and patients with advanced periodontitis.

The adhesion molecule, CD11b/CD18, plays a role in host defense against bacterial infections owing to its involvement in cell migration and phagocytosis. We examined the kinetics of CD11b expression on neutrophils isolated from peripheral blood (PB-PMNs) and gingival crevicular fluid (CF-PMNs) in subjects with healthy gingivae and in patients with advanced periodontitis in order to assess if CF-PMNs respond differently in regard to CD11b expression from PB-PMNs isolated from healthy or periodontitis subjects. CF-PMNs or formylmethionylleucylphenylalanine (fMLP)-stimulated PB-PMNs were incubated in buffer with or without divalent cations for 60, 90, or 110 minutes. Plasma membrane (surface) CD11b as measured by flow cytometry was found to be reduced with time when cells (PB-PMNs or CF-PMNs) from either controls or patients were treated with calcium- and magnesium-free buffer. However, when CF-PMNs were treated with buffer containing Ca++/Mg++, surface CD11b expression increased on cells from both controls and patients. The reduction in CD11b expression on PB-PMNs is significantly greater than that measured on CF-PMNs over time. Therefore, CF-PMNs respond differently from PB-PMNs which have been artificially stimulated with fMLP in regard to kinetics of CD11b expression on the plasma membrane.