Vaccines evoke an immune response to an antigen, and the immune system reacts by producing T cells and antibodies. The B memory cells remember the antigen so that if the body encounters it later, antibodies can be produced by B cells to break down the antigen. For bacteria with a polysaccharide coating, the immune response creates B cells independent of T cell stimulation. By<unk> ng the polysaccharide to a protein carrier, a T cell response can be induced. Normally, polysaccharides by themselves cannot be loaded onto the major histocompatibility complex (MHC) of antigen presenting cells (APC) because MHC can only bind peptides. In the case of a<unk> , the carrier peptide linked to the polysaccharide target antigen is able to be presented on the MHC molecule and the T cell can be activated. This improves the vaccine as T cells stimulate a more vigorous immune response and also promote a more rapid and long-lasting immunologic memory. The<unk> on of polysaccharide target antigen to the carrier protein also increases efficiency of the vaccine, as a non<unk>  against the polysaccharide antigen is not effective in young children. The immune systems of young children are not able to recognize the antigen as the polysaccharide covering disguises the antigen. By combining the bacterial polysaccharide with another antigen, the immune system is able to respond.
Conjugate vaccine
Synthetic vaccine
Subunit vaccine
Attenuated vaccine
Genetically modified vaccine
Inactivated vaccine
Cell-based vaccine
Heterologous vaccine