Neutrophil chemotactic substances in different fractions of soluble dental plaque material

Extracts of 4‐day‐old dental plaque were fractionated on Sephadex® columns (G‐10; G‐25; G‐200). Five fractions were selected from the protein and conductivity peaks obtained in chromatograms. The chemotactic activity elaborated by the fractions was tested in the Boyden's in vitro model system. The permeability altering capacity of the plaque fractions was tested in vivo in a wound chamber. The results from the in vitro experiments demonstrated that all fractions were chemotactic for rabbit neutrophil leukocytes. Substances of a low molecular size (mol. wt.∼5.000) elaborated, however, the peak chemotactic activity. The results from the in vivo experiments showed that the plaque fractions induced an increased (1) vascular permeability, and (2) emigration of leukocytes from a granulation tissue vasculature. The most pronounced emigration and exudation was induced by the low molecular size fraction (mol.wt.∼5.000).