Defining High Endothelial Venules and Tertiary Lymphoid Structures in Cancer

Abstract

High endothelial venules (HEVs) are structurally distinct blood vessels that develop during embryonic and neonatal life in all secondary lymphoid organs except the spleen. HEVs are critical for initiating and maintaining immune responses because they extract naïve and memory lymphocytes from the bloodstream, regardless of antigen receptor specificity, and deliver them to antigen-presenting cells inside lymph nodes under homeostatic conditions. HEVs also develop postnatally in nonlymphoid organs during chronic inflammation driven by autoimmunity, infection, allografts, and cancer. Extranodal HEVs are usually surrounded by dense lymphocytic infiltrates organized into lymph-node like, T- and B-cell-rich areas called tertiary lymphoid structures (TLS). HEV neogenesis is thought to facilitate the generation of tissue-destroying lymphocytes inside chronically inflamed tissues and cancers.We are studying the mechanisms underpinning HEV neogenesis in solid cancers and the role of homeostatic T-cell trafficking in controlling cancer immunity. In this chapter we describe methods for identifying HEV in tissue sections of cancerous tissues in humans and mice using immunohistochemical staining for the HEV-specific marker peripheral lymph node addressin (PNAd). L-selectin binding to PNAd is a necessary first step in homeostatic lymphocyte trafficking which is the defining function of HEV. We also describe methods to measure L-selectin-dependent homing of lymphocytes from the bloodstream into lymphoid tissues and tumors in preclinical cancer models.

Enhanced antitumor immunity through sequential targeting of PI3Kδ and LAG3

“… 13 The HEV phenotype is characterized by expression of PNAd with coexpression of the pan-endothelial cell marker, CD31 and a plump and cuboidal morphology ( figure 5H, I ). 26 Vessels displaying this phenotype, thus confirming the presence of HEV, were detected in 18% and 89% of 4T1 tumors in WT and PI3Kδ D910A mice, respectively. The average area of HEVs was calculated (μm 2 ) per tumor in these ( figure 5J ) and in PI-3065-treated mice ( figure 5K ).…”

“…Sections were stained for high endothelial venules (HEV) as described previously. 26 Briefly, antigen retrieval was performed in Tris-EDTA (10 mmol/L; 1 mmol/L, pH 9.0). Endogenous peroxidase activity was quenched using 1% H 2 O 2 /MeOH and non-specific binding was blocked with 2.5% horse serum.…”

Tumor Endothelial Cells (TECs) as Potential Immune Directors of the Tumor Microenvironment – New Findings and Future Perspectives

“…Similar to SLO, TLS are closely associated with specialized vessels called high endothelial venules (HEV), which are located in the peripheral zone of the TLS (Martinet et al, 2011) and characteristically express PNAd, MECA79 and selectin ligands (Jones et al, 2018), all of which are required for lymphocyte homing (Streeter et al, 1988;Girard and Springer, 1995) (Figure 2A). Tumor-secreted cytokines (CXCL13 and IL-7) induce the formation of lymphoid tissue inducer (LTi) cells (Meier et al, 2007), which interact with local stromal cells via Lymphotoxin-α1β2 (Colbeck et al, 2017a).…”

“…TEC lining HEV are characterized by the HEV specific marker PNAd. Binding of T cell expressed L-selectin to PNAd on TEC implies the first step of lymphocyte adhesion, followed by further interactions, such as binding of integrin ligands (ICAM1, VCAM1, and MADCAM1) with the respective receptors (LFA1, VLA4, and α4β7) (Jones et al, 2018). Lymphocytes can then transmigrate into the structured zones of the TLS, where they become activated upon interaction with local DC (Sautès-Fridman et al, 2019).…”

High Endothelial Venules and Pancreatic Ductal Adenocarcinoma: A potential game changer

“…As a pancreatic surgical oncologist and a cancer researcher, I read with great interest the study by Bahmani et al titled: Ectopic High Endothelial Venules in Pancreatic Ductal Adenocarcinoma: A Unique Site for Targeted Delivery, and congratulate them on conducting an elegant study and sharing their promising findings [5]. High Endothelial Venules (HEVs) are specialized post-capillary venules found in the para-cortical areas of lymph nodes (LNs) and they are distinct functionally and morphologically from ordinary venules; they are first characterized in the field of immunology [6]. These studies suggest that HEV pay a central role in lymphocyte trafficking to LNs.…”