One recent approach to vaccine development has been production of peptide vaccines. In these vaccines, antigenic peptides are injected instead of whole bacteria or viruses. Peptide vaccines have not been particularly useful against viral pathogens because viral infections require a CD8+ T cell mediated immune response. Why is a peptide vaccine unable to create such a response?

Explanation below

Explanation:

Immunization is the process of protecting the body from infections. This can be divided into two, namely

1. Natural immunization

2. Artificial immunization

Natural immunization is the one that is being developed by the body naturally, to protect the body from infections. This is usually known as the white blood cells.

Artificial immunization is being developed through the introduction of atenuated organisms into the body, so that the body can react by producing antibodies against that infectious organisms. This is known as vaccination.

The peptide vaccines have been developed for the body to be able to produce antibodies against some infections.

It should be noted that, owing to the relatively small size of peptides, they are often weakly immunogenic by themselves and therefore require carrier molecules, to add chemical stability and adjuevating for the induction of a robust immune response.