Accumulating evidence suggests that Fusobacterium nucleatum contributes to the progression and carcinogenesis of an increasing number of tumours, including colorectal, pancreatic, esophageal, breast cancer, by inducing inflammation and suppressing host immunity, as well as of Alzheimer's disease. F. nucleatum is a therapeutic target for antibiotic treatment and a live attenuated strain has also been explored for a vaccine against colorectal cancer. Bacterial surface glycans include lipopolysaccharide (LPS) that perform multiple functions and are crucial in the immune surveillance and mediate colonization, symbiosis, virulence, pathogenesis, immune evasion. In some cases, bacteria can also mimic the glycan structures of the host, in an event called molecular mimicry, to establish infection, dampening host immune recognition. Understanding the role of glycans and glycosylation in immunity is critical to fully understand etiology and progression of relevant immune diseases. The components of lipopolysaccharides (LPS) present on the surface of the Gram-negative bacteria are therefore important for development of glycoconjugate vaccine. Several human beneficial and harmful bacteria pathogens have evolved the ability for displaying host immune receptors ligands on the cell surface. In particular, F. nucleatum apparently acquired the ability to evade immunosurveillance via molecular mimicry, this strongly correlating its promotion of CRC progression through the generation of a pro-inflammatory environment. We already showed that F. nucleatum ssp. animalis interacts with Siglec-7 expressed on innate immune cells, observed using either F. nucleatum-derived outer membrane vesicles (OMVs) and lipopolysaccharide (LPS). Therefore, the improvement of our understanding of bacterial envelope compositions, structure, molecular recognition and interaction with host receptors (figure ). The trisaccharides contain all-rare sugars such as 2-acetamido-2-deoxy-Dglucuronic acid (GlcNAcA) and 2,4,6-trideoxy-2-acetamido-4-amino-D-Galp (AAT) not found in human hosts, which makes them potential candidates for vaccine development. Although the only difference between the two structures I and II is the presence or absence of 4Nacetylation in the AAT sugar, it imparts a zwitterionic character to structure II as the two free NH2 group and two carboxylic acids can create complimentary charges at physiological pH.