Figure 8. Schematic diagram illustrating the dual mechanisms of action of TNFα leading to the trafficking of neutrophils into and within the lymphatic vasculature upon acute inflammation in vivo.

During the acute inflammatory response of the tissue following antigen sensitisation, endogenous TNFα release primed the freshly recruited neutrophils. This cytokine allow these leukocytes to be attracted to the lymphatic vessels in a CCR7 dependent manner (intravasation). Furthermore, endogenous TNFα also stimulate the lymphatic endothelium to express ICAM-1 on their surface, allowing the neutrophils present in the lymphatic vessels to adhere and crawl along the luminal side in the correct direction toward the flow of the vessel.