Lipopolysaccharide induces rapid loss of follicular dendritic cell-secreted protein in the junctional epithelium.

UNLABELLED Oshiro A, Iseki S, Miyauchi M, Terashima T, Kawaguchi Y, Ikeda Y, Shinomura T. Lipopolysaccharide induces rapid loss of follicular dendritic cell-secreted protein in the junctional epithelium. J Periodont Res 2012; 47: 689-694. © 2012 John Wiley & Sons A/S Background and Objective:  We have previously reported that mRNA encoding follicular dendritic cell-secreted protein (FDC-SP) is expressed specifically in the junctional epithelium at the gingival crevice. Other tissues, such as tonsil, prostate gland and trachea, also express high levels of FDC-SP. These tissues participate in a range of functions closely related to innate immunity. Therefore, it is hypothesized that FDC-SP plays a crucial role in close association with the host defense system within the gingival crevice. Accordingly, the main aim of this study was to investigate the expression and localization of FDC-SP in and around the junctional epithelium and to observe the dynamic changes of FDC-SP in experimental inflammation. MATERIAL AND METHODS   We examined, immunohistochemically, the expression of FDC-SP in the junctional epithelium using a specific antibody raised in rabbit after immunization with a synthetic peptide derived from the hydrophilic region of FDC-SP. Experimental inflammation was induced in the upper molars of Wistar rats by applying bacterial lipopolysaccharide (LPS; 5 mg/mL in sterile saline) for 1 h. RESULTS   We confirmed that FDC-SP is present in the junctional epithelium in a pattern that is consistent with the expression of FDC-SP mRNA. Of special interest is that no FDC-SP was detectable in the junctional epithelium 3 h after transient topical treatment with LPS. CONCLUSION   The presence of FDC-SP in the junctional epithelium and its loss after LPS treatment strongly support our hypothesis of FDC-SP playing a crucial role in close association with the host defense system within the gingival crevice.