2010 Volume 30 Issue 2 Pages 124-128
Lymph nodes are small organs occurring in series along the course of lymphatic vessels. The parenchyma consists of a highly organized accumulation of lymphoid tissue, which recognizes antigens in the lymph and builds up a specific immune reaction against them especially in lymphoid follicles. Afferent lymphatic vessels come from the relatively huge area in the body and enter the node at multiple sites over its convex surface. Therefore, in this study, we investigated whether the parenchyma of the node is restricted by the afferent vessels. Two different colored tracers, inks (black and red) or fluorescent dyes (AlexaFluor® 488/594) , were subcutaneously injected in the tongue and gingiva of mice. At the indicated time, submandibular lymph nodes were dissected and examined under light and/or fluorescent microscopy. Injection of 0.1 ml of a tracer at 1 h showed that the tracers entered into the whole area of the node whereas a 0.02 ml injection showed that traces localized some restricted area in the node. The lymph node at 1 h after the injection of two tracers showed that both traces penetrated into different parts of the node. Furthermore, at 48 h two different tracers were detected at the different follicles. These results indicated the regional restriction of lymphoid follicles in the node which might be regulated by the different site of afferent vessels to the node and suggest that each of the lymphoid follicles in a node respond to different antigens.
