Laboratory suncus: a new model animal for tonsil research.

Palatine and tubal tonsils of normal and horseradish peroxidase (HRP) sensitized laboratory suncuses (Suncus murinus) were examined by immunoelectron microscopy. The individual tonsil consisted of lymphoepithelial symbiosis containing M cells and a lymph nodule. The high-endothelial venules and efferent lymphatics were situated in the parafollicular region of the nodule. Staining of the frozen tonsil sections by our recently developed anti-Suncus T and B lymphocyte monoclonal antibodies revealed that T cells occupied the parafollicular zone and B cells localized within the follicles. In the present intra-tympanic cavity HRP sensitization, numerous HRP-antibody producing cells were seen not only in the tubal tonsils but also in their regional lymph nodes, spleen and palatine tonsils. The same HRP-antibody was rarely detected within the submesangial regions of the kidney. These findings presume that Suncus tonsil is homologous to the human tonsil. The Suncus is, therefore worthy as a model animal for tonsil research.