Low molecular-weight proteins in human gingival crevicular fluid

Samples of gingival crevicular fluid (GCF) were collected in 30 volunteers with inflamed gingiva, using either capillary tubes (cGCF) or Durapore strips (sGCF). They were examined, together with samples of serum from the same patients, by sodium dodecyl sulphate-polyacrylamide gel electrophoresis and/or by two-dimensional electrophoresis, followed by silver staining. The results confirmed that the distribution of the major proteins in GCF is similar to that found in serum. However, an 8.5 kDa protein was found in gingival fluid but not in serum. The low molecular-weight protein appears to decrease with time of fluid sampling with both techniques, and does not originate either from blood or from the cellular fraction of GCF. Two-dimensional electrophoretic analysis suggested that it may consist of several polypeptides.