Helicobacter pylori(Hp)is responsible for chronic gastritis,peptic ulcers,and even gastric cancers.Currently,there is no vaccine to prevent or treat Hp infections.Here,we described the chemical synthesis of α-1,6-glucans with different lengths(di-to hexasaccharide),which are present in the core oligosaccharide of Hp lipopolysaccharide(LPS).The 1,2-cis-glucosidic bonds were constructed successfully using a synergistic glycosylation strategy based on acyl remote participation and solvent effects.The results of glycan microarrays indicated that all synthesized α-1,6-glucan fragments possessed a strong binding to IgG antibodies in both rabbit serum immunized with Hp O1 LPS and patient serum infected with Hp.The α-1,6-linked trisaccharide exhibited strong binding affinity to anti-LPS rabbit IgG antibodies.The α-1,6-glucan trisaccharide and pentasaccharide elicited a strong response to IgG antibodies in sera of most Hp-infected patients.Some patients'sera exhibited strong binding activity with α-1,6-linked disaccharide.The results suggest that the α-1,6-glucan disaccharide,trisaccharide and pentasaccharide could be important carbohydrate antigen fragments in Hp lipopolysaccharide.