The post-natal development of lymph nodes in mice.

A total of ten major lymph node stations have been studied in ICR-strain mice at various time intervals between birth and the age of four weeks. Comparison of lymph node volumes and of volume changes during the observation period revealed that the mesenteric lymph node (MLN) complex was larger at birth and grew at a faster rate than all other nodes. A distinct numerical increase of cortical lymphocytes in MLN at the end of the first week of life was interpreted to be the result of both immigration of T cells and moderate local proliferation, while the quantitatively more important second phase of growth at the age of between two and three weeks might be the consequence of local lymphocyte production. The comparatively modest changes in lymph nodes removed from the gut (axillary and popliteal nodes) could be explained as being due in large measure to immigration of lymphocytes originating in gut-associated lymphoid tissues (GALT).