The Cytokines, Interleukin-1β, Interleukin-6 and Interferon-γ Upregulate the Expression of Intercellular Adhesion Molecule-1 (ICAM-1) in Rat Thyroid Cell Line, FRTL-5

OBJECTIVES: Recently, the role of adhesion molecules in the immune system has been recognized. ICAM-1 plays an important role in a variety of inflammatory and immune mediated mechanisms, including recruitment and targeting of lymphocytes. We observed the effects of cytokines on expression of rat homologue of human intercellular adhesion molecule-1 in rat thyroid cell line, FRTL-5. METHODS: We have examined expression of rat intercellular adhesion molecule-1 (ICAM-1, CD54), a homologue of human intercellular adhesion molecule-1, by immunocytochemistry (immunoperoxidase staining) in the continuously growing rat thyroid cell line, FRTL-5. RESULTS: Low level of ICAM-1 expression was noted at basal condition and this basal expression was not influenced by thyrotropin. Expression in rat homologue of ICAM-1 is increased by interferon-γ, interleukin-1β and interleukin-6 with a dose dependent manner. CONCLUSION: These results show that a pure line of rat thyroid cells can express an ICAM-1 homologue and this is directly enhanced by cytokines such as rat interferon-γ, human interleukin-1β and interleukin-6. Expression of this homologue is partially responsible for lymphocyte adhesion to thyroid cells, which is likely to be a major event in T cell recognition of thyroid antigens in autoimmune thyroiditis.