Quantification of secretory leukocyte protease inhibitor (SLPI) in oral gargle specimens collected using mouthwash

Abstract

BackgroundSecretory leukocyte protease inhibitor (SLPI) is an innate immunity-associated protein known to inhibit HIV transmission, and is thought to inhibit a variety of infectious agents, including human papillomaviruses (HPVs). We aimed to optimize an established ELISA-based SLPI quantification assay for use with oral gargle specimens collected using mouthwash, and to assess preliminary associations with age, smoking status, and alcohol intake. MethodsOral gargle supernatants from 50 individuals were used to optimize the Human SLPI Quantikine ELISA Kit. Sample suitability was assessed and quality control analyses were conducted. ResultsSalivary SLPI was successfully recovered from oral gargles with low intra-assay and high inter-individual variability. Initial measurements showed that salivary SLPI varied considerably across individuals, and that SLPI was inversely associated with age. ConclusionsThis optimized assay can be used to examine the role of SLPI in the acquisition of oral HPV and other infections.