use of adjuvants and peptides in modern vaccines?
In many vaccines, there are two components: One immunogenic substance, these can be parts or complete (inactivated) pathogens (for example the small pox vaccination), peptides or proteins (like the tetanus vaccination) or polysacceride components from the capsule of bacteria (for example against MenC). Against these components the actual immune response is directed. See references 1 to 3 for some more details.

Then they can (depending on the vaccine) contain adjuvants, which enhance the immunologic reaction of the body. This is done either to enhance the reaction and to get a proper immune reaction but also to be able to reduce the amount of injected antigen. So the adjuvant simply causes a general inflammatory reaction. Classically Alum (aluminium hydroxide is used here), newer adjuvants are squalen based oil-in water preparations or CpG olinucleotides (see references 4 and 5 for numerous examples on adjuvants and literature).

So what you basically do is to identify (more or less) a part of the pathogen which can serve as a vaccine and use this part for the vaccine.


Making Vaccines: How Are Vaccines Made
Designing Tomorrow's Vaccines
Strategies for designing and optimizing new generation vaccines
Dose Optimization Strategies for Vaccines: The Role of Adjuvants and
New Technologies
Vaccine Adjuvants Review