Oral use of interferon-alpha stimulates ISG-15 transcription and production by human buccal epithelial cells.
ISG-15 is a 15-kDa protein encoded by an interferon (IFN)-stimulated gene (ISG), which is transcriptionally regulated by IFN-alpha and IFN-beta. Considered as part of the cytokine network, ISG-15 has the potential to amplify the immunomodulatory effects of these IFNs by enhancing IFN-gamma production, natural killer cell proliferation, and lymphokine-alphactivated killer cell cytotoxicity. To understand better the mechanism(s) of action of orally administered IFN-alpha, we have studied the effect of IFN-alpha on ISG-15 gene expression by human buccal epithelial cells (BEC). For in vitro studies, ISG-15 mRNA and protein levels were measured in BEC incubated for 0.5, 2, and 9 h with 100 or 1,000 IU/ml of human lymphoblastoid IFN-alpha. For in vivo studies, ISG-15 mRNA was measured in BEC samples collected at baseline, and 0.5, 2, and 9 h after 5-20 min of oral rinsing with 10 ml of IFN-alpha (1,000 IU/ml). ISG-15 mRNA was measured by reverse transcriptase polymerase chain reaction (RT-PCR), and ISG-15 protein production by Western Blot analysis. IFN-alpha augmented BEC ISG-15 gene expression in a concentration dependent manner both in vivo and in vitro. We conclude that orally administered IFN-alpha exerts its immunomodulatory effects in humans in part by upregulating the production of ISG-15 by BEC, thereby enhancing the immune reactivity of mucosa-associated lymphocytes.
Smith
J K
JK
Department of Internal Medicine, James H. Quillen College of Medicine, East Tennessee State University, Johnson City 37614-0622, USA. smithj@etsu.edu
Siddiqui
A A
AA
Krishnaswamy
G A
GA
Dykes
R
R
Berk
S L
SL
Magee
M
M
Joyner
W
W
Cummins
J
J
D000276:Adjuvants, Immunologic / Q000627:therapeutic use*; D000284:Administration, Oral; D002455:Cell Division / Q000187:drug effects; D002610:Cheek; D016207:Cytokines / Q000235:genetics*; D004847:Epithelial Cells / Q000187:drug effects*; D006801:Humans; D066298:In Vitro Techniques; D016898:Interferon-alpha / Q000627:therapeutic use*; D007694:Killer Cells, Natural / Q000166:cytology / Q000187:drug effects; D008970:Molecular Weight; D009061:Mouth Mucosa / Q000166:cytology / Q000187:drug effects*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013268:Stimulation, Chemical; D014158:Transcription, Genetic; D014452:Ubiquitins / Q000031:analogs & derivatives*
D000276:Adjuvants, Immunologic; D016207:Cytokines; D016898:Interferon-alpha; D014452:Ubiquitins; C074034:ISG15 protein, human