Sulfated glycans control lymphocyte homing.

Area of Science:

• Immunology
• Glycobiology
• Cellular Biology

Background:

• Lymphocyte homing to secondary lymphoid organs is essential for effective immune responses.
• Sulfated glycans, particularly 6-sulfo sialyl Lewis X (6-sulfo sLe(x)), are key ligands for L-selectin on high endothelial venules (HEVs).
• These interactions facilitate lymphocyte trafficking to peripheral lymph nodes.

Purpose of the Study:

• To review the functions of sulfated glycans in lymphocyte homing.
• To discuss their roles in both physiological and pathological conditions, including chronic inflammation and nasal allergy.
• To highlight the differential homing mechanisms for various lymphocyte subsets.

Main Methods:

• Review of existing literature on sulfotransferase-deficient mice models.
• Analysis of studies investigating lymphocyte homing to nasal-associated lymphoid tissues (NALT).
• Examination of the roles of L-selectin, P-selectin glycoprotein ligand-1, and CD44 in T cell homing.

Main Results:

• 6-sulfo sLe(x) is critical for CD4(+)CD25(-) T cell homing to NALT and is implicated in nasal allergy.
• Homing of CD4(+)CD25(+) regulatory T cells to NALT involves L-selectin-sulfated glycan interactions, P-selectin glycoprotein ligand-1, and CD44.
• The L-selectin-sulfated glycan pathway is also important for lymphocyte homing in chronic inflammatory conditions.

Conclusions:

• Different lymphocyte subsets utilize distinct carbohydrate-dependent homing mechanisms.
• Sulfated glycans play a significant role in lymphocyte trafficking in both normal immune function and disease states.
• Understanding these mechanisms is crucial for developing targeted therapies for inflammatory and immune disorders.