STUDIES ON THE ANTIBACTERIAL ACTION OF HUMAN SALIVA

I. A BACTERICIDIN FOR LACTOBACILLI

¹ Department of Periodontics and Endodontics, Division of Research, University of Washington, School of Dentistry, Seattle, Wash.

The results further characterize a salivary bactericidin active against Lactobacillus acidophilus, ATCC 4357.

The lactobacillus bactericidin was quantitated in paired parotid and submaxillary salivas collected from 25 individuals. Whereas there was marked variation between subjects ranging from 4 to 64 units of bactericidin per milliliter, there was less variation between the paired salivas of the two glands for given subjects. With one exception, the bactericidin levels in the parotid salivas were equal to or greater than those of the submaxillary salivas. Tests for the lactobacillus bactericidin in the serums of the various subjects were negative.

The lactobacillus bactericidin is apparently a salivary factor which requires a dialyzable heat stable cofactor for its activity. It is moderately heat stable over a wide range of pH with maximum stability at pH 5.5.

The lactobacillus bactericidin is not identical with salivary amylase or lysozyme.