The present invention relates generally to glycoconjugates comprising a saccharide covalently conjugated to a carrier protein through a spacer containing ((2-oxoethyl)thio)). In an aspect the invention provides oxo-eT linked glycoconjugates comprising a saccharide covalently conjugated to a carrier protein through a ((2-oxoethyl)thio) spacer having the formula (I):






wherein:
A is a group (C═X)m wherein X is S or O and m is 0 or 1;
B is a bond, O, or CH2; and when m is 0, B can also be (C═O);
R is a C2-C16 alkylene, C2-C16 heteroakylene, NH—C(═O)—C2-C16 alkylene, or NH—C(═O)—C2-C16 heteroakylene, wherein said alkylene and heteroalkylene are optionally substituted by 1, 2 or 3 groups independently selected from COOR′ where R′ is selected from H, methyl, ethyl or propyl.




The invention further relates to immunogenic compositions comprising such glycoconjugates, and to methods for the preparation and use of such glycoconjugates and immunogenic compositions.