Lymphocyte migration through the lymphatic sinuses of the chicken's lymph node

We have described the lymphocyte migration through the sinus wall of the lymph node. The sinuses showing lymphocyte migration are located in a given area of the node that might be comparable with the T-dependent deep cortex of the mammalian lymph nodes. The lymphocyte migration takes place through the cytoplasm of the endothelial cell presumably by formation of the transendothelial channels, which are produced by vesicles of the endothelial cell. The intensive vesiculation preceding the formation of transendothelial channels might indicate the direction of the migration. The absence of vesicles in the endothelial cell and the dilated intercellular space between the lymphocyte and endothelial cell suggest that the lymphocyte in the sinus wall may be "resting". The presence of the multivesicular body in the pseudopod or in the vicinity of the pseudopod of the lymphocyte may contribute to the migration.