mechanisticModerate evidence
Tumor immune evasion
Increased tumor sialylation engages inhibitory Siglecs and is associated with suppressed antitumor immunity, motivating checkpoint-style interventions.2
Glycome Atlas
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Glycome Atlas
process
Also known as sialic acid immune recognition, self-associated molecular patterns, sialoglycan checkpoint
Gal (β1-4) → GlcNAc; Neu5Ac (α2-3) → Gal
How to read these diagrams (SNFG)
Each shape is a class of sugar and each colour a specific one. Structures read right to left, with the reducing end (the point of attachment) on the right.
Plain-language answer
Many human cells cap their surface sugars with a special sugar called sialic acid. The immune system reads these caps as a self label, which helps it avoid attacking the body's own cells.1
This sialic acid self label is a built-in brake on immune activation. Tumors can exploit it to hide, and some pathogens copy it to evade defenses, which makes it a target for cancer immunotherapy research.12
Technical detail
Terminal sialylation of cell-surface glycans generates ligands for sialic-acid-binding Siglecs, providing a self-recognition axis that sets thresholds for immune activation and is subverted in cancer and infection.12
Because vertebrate cells densely display sialic acids that most pathogens lack, engagement of inhibitory Siglecs by these caps helps immune cells distinguish self from non-self and limit inappropriate activation.12
Hypersialylation by tumors and molecular mimicry by some microbes co-opt this inhibitory axis, a phenomenon being explored therapeutically through the Siglec-sialic acid checkpoint.2
Human relevance
Increased tumor sialylation engages inhibitory Siglecs and is associated with suppressed antitumor immunity, motivating checkpoint-style interventions.2
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References