Fig. 1.
Interactions of polysaccharide and conjugate vaccines with FDC, B, and Tfh cells in the GCs. (Top) Polysaccharide alone. (Middle) Polysaccharide coformulated with protein. (Bottom) Conjugate vaccine. Circles A and B show the two mechanisms by which conjugate vaccines can engage the TCR. In circle A, the peptide is loaded into the MHC molecule and is the antigen recognized by the TCR. In circle B, the TCR recognizes the sugar linked to the peptide anchored in the MHC. From ref. 11. Modified with permission from AAAS.