Measurement of Salivary Lysozyme

tions in whole saliva meets with consider-able difficulties due to the presence of mu-cins that precipitate during storage or cen-trifugation, resulting in considerable re-duction of the enzyme levels. I-2 Parotid saliva, known to be free of mucins, I would appear to be a more adequate substrate for lysozyme measurements, but our studies have shown that the apparent concentra-tions of lysozyme decline progressively dur-ing storage of parotid saliva. These problems can be obviated by a simple procedure that seems to result in the dissociation of lysozyme-mucin complexes and subsequent elimination of insolubil-ized mucins. Our studies were carried out with saliva samples collected from normal donors, after a two-hour fast and thorough mouthwash to remove debris. Whole saliva was collected by spontaneous salivation into a small beaker. Parotid saliva was ob-tained in a Curby cup during stimulation with a piece of candy for a period of 15 minutes. Both types of saliva samples were placed in a crushed ice bath immediately after collection and were processed in the hour following collection. Collected saliva was divided into four aliquots: one was stored at 4 C without further manipula-tion; a second aliquot was centrifuged at 14,000 rpm for 30 minutes in a cooled cen-trifuge (4 C) and the supernatant was used for further determinations; a third aliquot was filtered through a Millipore filter (Type HA, pore size 0.45 ixm) coupled to a