An immunogenic composition comprising: (a) a glycan conjugate including a carrier and one or more glycans, and optionally (b) an adjuvant; wherein each of the one or more glycans is conjugated with the carrier through a linker having the formula (III): wherein: X 1 is selected from -OR, wherein R is selected from an oxygen protecting group, optionally substituted C 1-10 alkyl, optionally substituted aryl, optionally substituted acyl, and optionally substituted imidoyl; or X 1 is selected from -SR, wherein R is selected from a sulfur protecting group, optionally substituted C 1-10 alkyl, optionally substituted aryl, optionally substituted acyl, and optionally substituted imidoyl; each instance of R 1 , R 2 , R 3 , R 4 , and R 5 is independently selected from hydrogen, halogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted heterocyclyl, optionally substituted aryl, -N 3 , - NO 2 , -N(R B ) 2 , -N(R A )C(O)R A , -OR A , -OC(O)R A , -SR A , -C(O)N(R B ) 2 , -CN, -C(O)R A , - C(O)OR A , -S(O)R A , -SO 2 R A , -SO 2 N(R B ) 2 , and -NHSO 2 R B ; R 6 is -OH; L is selected from hydrogen, halogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, -N 3 , -NO 2 , -N(R B ) 2 , -N(R A )C(O)R A , -OR A , -OC(O)R A , -SR A , -C(O)N(R B ) 2 , -CN, -C(O)R A , - C(O)OR A , -S(O)R A , -SO 2 R A , -SO 2 N(R B ) 2 , -NHSO 2 R B , and substituted heterocyclyl; wherein: each instance of R A is independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted heterocyclyl, and optionally substituted aryl; and each instance of R B is independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted heterocyclyl, and optionally substituted aryl; and provided the glycan conjugate is not of the formulae (III-a) or (III-b): or (a) a glycan conjugate including a carrier and one or more glycans, and optionally (b) an adjuvant; X 1 is selected from -OR, wherein R is selected from an oxygen protecting group, optionally substituted C 1-10 alkyl, optionally substituted aryl, optionally substituted acyl, and optionally substituted imidoyl; or X 1 is selected from -SR, wherein R is selected from a sulfur protecting group, optionally substituted C 1-10 alkyl, optionally substituted aryl, optionally substituted acyl, and optionally substituted imidoyl; each instance of R 1 , R 2 , R 3 , R 4 , and R 5 is independently selected from hydrogen, halogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted heterocyclyl, optionally substituted aryl, -N 3 , - NO 2 , -N(R B ) 2 , -N(R A )C(O)R A , -OR A , -OC(O)R A , -SR A , -C(O)N(R B ) 2 , -CN, -C(O)R A , - C(O)OR A , -S(O)R A , -SO 2 R A , -SO 2 N(R B ) 2 , and -NHSO 2 R B ; R 6 is -OH; L is selected from hydrogen, halogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted aryl, -N 3 , -NO 2 , -N(R B ) 2 , -N(R A )C(O)R A , -OR A , -OC(O)R A , -SR A , -C(O)N(R B ) 2 , -CN, -C(O)R A , - C(O)OR A , -S(O)R A , -SO 2 R A , -SO 2 N(R B ) 2 , -NHSO 2 R B , and substituted heterocyclyl; each instance of R A is independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted heterocyclyl, and optionally substituted aryl; and each instance of R B is independently selected from hydrogen, optionally substituted alkyl, optionally substituted alkenyl, optionally substituted alkynyl, optionally substituted heterocyclyl, and optionally substituted aryl; and provided the glycan conjugate is not of the formulae (III-a) or (III-b): or <EOS>