Functions of tonsils in the mucosal immune system of the upper respiratory tract using a novel animal model, Suncus murinus.
CONCLUSIONS
The human palatine tonsils and the nasopharyngeal tonsil were considered the defense mechanism against ingested or inhaled foreign pathogens. The current findings suggest that the tubal tonsils possess abilities of active transportation of foreign antigens, and will act as inductive and effector sites in the mucosal immune system. Our results also indicated a significant difference in roles of immune responses among individual tonsillar organs, suggesting functional sub-compartmentalization.


OBJECTIVE
To address the function of tonsils in inducing local immune responses, we evaluated the antigen uptake of tubal tonsils and the induction of specific immune responses in a small laboratory animal with both tubal and palatine tonsils, i.e. Suncus murinus.


METHODS
S. murinus were injected with 2 x 10(6) CFU of FITC-labeled Staphylococcus aureus via the right tympanic cavity. The distribution of the FITC-labeled S. aureus was examined under a fluorescent microscope. S. murinus were also immunized with 100 microg of ovalbumin (OVA) mixed with 2 microg of cholera toxin (CT) via the right external ear meatus every 2 days for 2 weeks. One week after the final immunization, sera, pairs of tubal and palatine tonsils, and the neck lymph nodes were obtained to evaluate the induction of specific immune responses.


RESULTS
The FITC-labeled S. aureus particles were detected in tubal tonsils and also in cervical lymph nodes. Total IgA-producing cells and OVA-specific antibody-producing cells were identified in the immunized tubal tonsils. Trans-external ear meatus immunization of tubal tonsils also evoked systemic antibody responses.
Suzumoto
Masaki
M
Department of Otolaryngology-Head and Neck Surgery, Wakayama Medical University, Kimiidera 811-1, Wakayama-shi 641-0032, Wakayama, Japan. suzumoto@wakayama-med.ac.jp
Hotomi
Muneki
M
Fujihara
Keiji
K
Tamura
Shinji
S
Kuki
Kiyonori
K
Tohya
Kazuo
K
Kimura
Michio
M
Yamanaka
Noboru
N
D000234:Adenoids / Q000276:immunology* / Q000473:pathology; D000818:Animals; D000917:Antibody Formation / Q000276:immunology; D002772:Cholera Toxin / Q000276:immunology; D004432:Ear, Middle / Q000276:immunology / Q000473:pathology; D018928:Immunity, Mucosal / Q000276:immunology*; D007124:Immunoenzyme Techniques; D007070:Immunoglobulin A / Q000378:metabolism; D007074:Immunoglobulin G / Q000378:metabolism; D007075:Immunoglobulin M / Q000378:metabolism; D008198:Lymph Nodes / Q000276:immunology / Q000473:pathology; D008297:Male; D010047:Ovalbumin / Q000276:immunology; D014066:Palatine Tonsil / Q000276:immunology* / Q000473:pathology; D020545:Respiratory Mucosa / Q000276:immunology* / Q000473:pathology; D012788:Shrews; D013211:Staphylococcus aureus / Q000276:immunology
D007070:Immunoglobulin A; D007074:Immunoglobulin G; D007075:Immunoglobulin M; D010047:Ovalbumin; D002772:Cholera Toxin