The present invention discloses modified Streptococcus pneumoniae pneumolysin proteins that contain glycosylation site consensus sequences. The invention also discloses a conjugate comprising a modified pneumolysin protein and an antigen (for example a Streptococcus pneumoniae saccharide antigen), wherein the antigen is linked (either directly or through a linker) to an amino acid residue of the modified pneumolysin protein.
