Lymph node vascular plasticity during Herpes Simplex Virus Type II infection.

Lymph node (LN) blood supply has long been thought to be integral to the immune response. Recently, the phenomenon of remodeling of the LN feed arteriole during viral infection was demonstrated as a key component of induction of an effective adaptive immune response. Here, the data presented show that during infection the LN feed arteriole is capable of non-pathogenic, reversible, outward remodeling peaking seven days post-immunization before returning to pre-infection size. Using pharmacological blockade and genetic ablation models, the remodeling process is demonstrated to be dependent upon the presence of CD4⁺ T cells in the LN, the expression of endothelial nitric oxide synthase (eNOS), tumor necrosis factor alpha, and age, as well as influenced by mast cells. Collectively, these results demonstrate key links between immune response, arteriole remodeling, and vascular mediators and represent a novel mechanism of vascular modulation of immunity. --P. ii.