PREFERENCE OF LYMPHOCYTE-HOMING TO HIGH ENDOTHELIAL VENULES IN PALATINE TONSILS OF MUSK SHREW (SUNCUS-MURINUS)

We studied the lymphocyte-homing to palatine tonsils of the musk shrew , a new experimental animal originally developed in Japan. The tonsils of the animals have typically high endothelial venules (HEV) in the p arafollicular region. The in vivo migration test showed that blood-cir culating lymphocytes were able to home to the tonsils through the HEV. The in vitro lymphocyte-HEV binding assay clearly indicated the bindi ng preference of the lymphocytes to be the tonsillar HEV. First, bindi ng of B cells to the tonsillar HEV was seen to a greater extent than t hat of T cells, which was consistent with the result in the assay of P eyer's patch. Second, binding of lymphocytes from axillar and inguinal lymph nodes was similar to that of lymphocytes from the mesenteric ly mph nodes, which differed from the result in the assay of Peyer's patc h. These findings suggest that, in the musk shrew, the regulation of l ymphocyte-homing through the HEV is different in the tonsil and Peyer' s patch, at least in part. These homing properties of musk shrew tonsi ls may reflect their immunological role in the local response against oral antigens.