Establishment of immortalized human minor salivary gland cells and chemokine expression induced by IFN-γ, TNF-α, and IL-1β.

The role of inflammatory response by salivary gland cells is considered to be important in the pathogenesis of salivary gland chronic inflammation, as seen in Sjögren's syndrome patients. The primary salivary gland cell cultures are required to investigate such inflammatory responses, though primary cells exhibit a limited replicative short lifespan with only a few passages. An immortalized human minor salivary gland cell line, NSG cells, was established by transfection with human telomerase reverse transcriptase (hTERT) and SV40 large T antigen (SV40LT). The effects of IFN-γ, TNF-α, and IL-1β on chemokine expression in those cells were then examined. Following hTERT expression vector and SV40LT vector transfections into minor salivary gland cells with a non-viral method, real-time PCR was employed to examine the effects of IFN-γ, TNF-α, and IL-1β on chemokine mRNA expression. Additionally, ELISA was used to examine the effects of combinations of IFN-γ, TNF-α, and IL-1β on CXCL10 and CXCL1 protein expressions. NSG cell growth was found to continue for more than 100 population doublings and the cells constitutively expressed immortalized-related and salivary gland-associated genes. IFN-γ, TNF-α, and IL-1β each increased the examined chemokines by various levels. Both TNF-α and IL-1β separately increased IFN-γ-induced CXCL10 in the NSG cells, whereas IFN-γ decreased CXCL1 induced by TNF-α or IL-1β. An immortalized human minor salivary gland cell line was established by hTERT and SV40LT transfection. The examinations showed that IFN-γ, TNF-α, and IL-1β have important roles for development of salivary gland inflammation, such as Sjögren's syndrome.