An ultrastructural study of lymph nodes in antilymphocyte serum-treated mice

The cytoarchitecture of regional axillary lymph nodes of C57BL/6 mice with DBA/1 skin allografts were examined by light microscopy (LM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Lymph nodes from skin-grafted mice injected with rabbit anti-mouse lymphocyte serum (ALS) or normal rabbit serum (NRS) were examined ultrastructurally for the pattern of distribution, density and surface topography of their cellular constituents. The lymph node cortex consisted of smooth surface polyhedral-shaped cells tightly packed in the reticulum. A homogeneric population of lymphocytes more spherical in shape and more loosely distributed occupied the follicular region of the cortex. These cells exhibited surface microvilli and were similar in appearance to the free lymphocytes observed in the sinusoidal spaces. Post-capillary venules containing highly villous lymphocytes were observed in the deep cortex. Degradation of cellular organization and cell damage was observed in lymph nodes from ALS-treated mice. These alterations were believed to be a direct effect of ALS. This conclusion was based on the character of the cell damage observed in isolated lymphocytes, in suspension exposed to ALS with and without complement.