Interferon-gamma expression in the inner ear of rats following secondary immune reaction in the endolymphatic sac.
Recently, we demonstrated increased intercellular adhesion molecule-1 (ICAM-1) expression in the inner ear of systemically pre-sensitized rats after antigen [keyhole limpet hemocyanin (KLH)] challenge into the endolymphatic sac (ES), in good correlation with the cellular infiltration. Interferon-gamma (IFN-gamma) is an important cytokine that upregulates the expression of ICAM-1. Here, we report upregulation of IFN-gamma expression in the inner ear of systemically pre-sensitized rats after antigen (KLH) challenge into the ES. Immunoreactivity for IFN-gamma was detected in the spiral ligament, suprastrial region, spiral modiolar veins, spiral collecting venules, surface membrane of the perilymphatic compartment and perilymphatic space of immunized, but not control, rats. IFN-gamma expression was detected at 1.5 h post-challenge, peaked at 6 h and gradually returned to baseline levels after 7 days. Interestingly, the time kinetics of IFN-gamma expression were in good correlation with those of ICAM-1. These observations demonstrate that antigen challenge into the ES induces IFN-gamma expression, which can then upregulate ICAM-1 expression and induce cell infiltration, suggesting that IFN-gamma may play a crucial role in immune-mediated inner ear diseases.
Pawankar
Ruby
R
Department of Otolaryngology, Nippon Medical School, Tokyo, Japan. Pawankar_Ruby/ent@nms.ac.jp
Tomiyama
Shunichi
S
Ikezono
Tetsuo
T
Nonaka
Manabu
M
Jinnouchi
Ken
K
Yagi
Toshiaki
T
D000818:Animals; D007758:Ear, Inner / Q000276:immunology* / Q000473:pathology; D018159:Endolymphatic Hydrops / Q000276:immunology* / Q000503:physiopathology; D004712:Endolymphatic Sac / Q000276:immunology*; D005620:Freund's Adjuvant / Q000276:immunology; D006433:Hemocyanins / Q000276:immunology; D007111:Immunity, Cellular; D007150:Immunohistochemistry; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D007371:Interferon-gamma / Q000096:biosynthesis*; D007700:Kinetics; D023421:Models, Animal; D051381:Rats; D015854:Up-Regulation
D018799:Intercellular Adhesion Molecule-1; D007371:Interferon-gamma; D005620:Freund's Adjuvant; D006433:Hemocyanins; C032808:keyhole-limpet hemocyanin