Profiling of inflammatory cytokines produced by gingival fibroblasts after human cytomegalovirus infection

Abstract

Introduction: The purpose of this study was to determine the profile of inflammatory cytokines that are produced after in vitro infection of gingival fibroblasts with human cytomegalovirus (HCMV).

Materials and methods: Gingival fibroblasts were infected with the Towne strain of HCMV and the cytokine profile in the supernatant was studied using a human inflammation antibody array. Expression of messenger RNA (mRNA) using reverse transcription-polymerase chain reaction for interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha) was also analyzed in infected gingival fibroblasts and gingival specimens from subjects with and without periodontitis according to HCMV detection. HCMV was determined in subgingival samples by nested polymerase chain reaction.

Results: Gingival fibroblasts produced mainly IL-1alpha, IL-12p40, IL-12p70, IL-6, TNF-alpha, and IL-1beta after HCMV infection. Expression of mRNA for IL-1beta and TNF-alpha was increased after HCMV infection. Production of IL-1beta and TNF-alpha was increased in HCMV-positive periodontitis specimens. In addition, infected gingival fibroblasts produced more IL-8, monocyte chemoattractant protein 1, macrophage inflammatory proteins 1alpha, and 1beta over time postinfection in comparison to baseline. The lowest production of all cytokines studied corresponded to IL-2, IL-4, IL-13, and interferon-gamma. A decreasing production pattern was observed for granulocyte-macrophage colony-stimulating factor, IL-7, and IL-17 while IL-11 and macrophage colony-stimulating factor were increased at 72 h postinfection.

Conclusions: HCMV infection in gingival fibroblasts upregulated the production of proinflammatory-related cytokines and chemokines. The expression of IL-1beta and TNF-alpha was increased both in vitro and in specimens from HCMV-positive subjects with periodontitis. The overproduction of proinflammatory cytokines and chemokines as a result of viral infection should be considered an important pathogenic mechanism linking HCMV to periodontitis in vivo.