User:Chunshengyan/Peptide-based synthetic vaccine

Peptide-based synthetic vaccines are the vaccines made from chemically synthetic peptides which are consist of amino acids. The peptide mimics the epitopes of the antigen that triger direct and potent immune response. In the future, the synthetic vaccine may not only provide protection again the disease but also cure the disease.

Advantages of Peptide-based vaccines:

1.   The vaccines are fully synthesized by chemical synthesis and can be treat as chemical entity.

2.   With more advanced solid phase peptide synthesis (SPPS) using automation and microwave techniques, the production of peptides becomes faster, more efficient and cheaper.

3.   The vaccines do not have any biological contamination since they are chemically synthesized.

4.   The vaccines are water-soluble and can be kept stable under simple conditions.

5.   The peptides can be specially designed for specificity. A single peptide vaccine can be designed to have mutiple epitopes to generate immune response for several diseases.

6.   The vaccines only contain a short peptide chain, so they are less like to lead to allergic or auto immune response.

Disadvantages： poor immugenicity, unstable in cells, lack of native conformation, only effective for limited population.

Epitope Design:

The whole petide vaccine is to mimic the epitope of antigen, so epitope design is the most import stage of vaccine development and requires an accurate understanding of the amino acid sequence of the immunogenic protein interested. The designed epitope is expected to generate strong and long-period immuresponse against the pathogen.

1.   Not necessary to be the dominant epitope of the pathogen. THe non dominant epitope could generate stonger immune response. Ex. APR-1 epitopes other than Necator americanus APR-1 protein which is the dominant epitope shows better abilities to induce antibiotics.

2.   Take hypersensitivity into consideration. Ex. Some IgE-inducing epitopes cause hypersensitivity reaction due to the overlap with IgG epitopes in the Na-ASP-2 protein from hookworm.

3.   Some short peptide epitopes need elongating to amintain the native conformation. Ex. B-cell epitopes could only have 5 amino acids, but to induce immune response, sequence from yeast GCN4 protein is used to