Histatins are human salivary antifungal proteins which are enriched in histidines. In a previous study we have quantitated histatins in salivary secretions and whole saliva (WS) using a zinc precipitation method (Flora et al., 2001). High histatin concentrations, comprising histatins 1, 3 and 5, were found in human parotid secretions (PS) and submandibular/sublingual secretions (SM/SL) with levels ranging between 4.5-5.5 mg% and 14.0-18.4 mg% in PS and SM/SL, respectively. WS histatin levels were significantly lower ranging between 0.22-0.54 mg%. Objective: To investigate the basis for this histatin concentration difference between pure glandular secretions and WS. Methods: Pure histatin 1, 3 or 5 were added to boiled or unboiled WS samples from one individual to a final concentration of 50 µg/ml. At various time intervals (0, 1, 5, 10, 30 and 60 min) 1-ml samples were removed, boiled and subjected to zinc precipitation. The precipitate containing the histatins was analyzed by HPLC for quantification using peak integration and comparison to histatin standards. Results: Histatin 1, 3 or 5 added to unboiled WS rapidly and completely disappeared within 5 min of incubation. Histatins added to boiled WS were relatively stable over the 60 min time interval but the amount of histatin recovered from 1-ml at t = 0 min was always lower than the 50 µg added. Typically, the reduction of histatins amounted to 26% for histatin 1, 37% for histatin 3 and 61% for histatin 5. Conclusion: The rapid disappearance of histatins from unboiled WS and the protection of histatins by boiling suggests that these proteins, once in the oral cavity, undergo proteolysis. The 26-61% loss of measurable histatins from boiled WS points towards the association of histatins with other proteins forming complexes that are not accounted for by the quantitation method. Supported by NIH/NIDCR Grants DE05672, DE07652 and DE14950.

Back to the Salivary Research Program
Back to the IADR/AADR/CADR 82nd General Session (March 10-13, 2004)

Top Level Search