when preparation of modern vaccines we generally use a part of the microbe or the antigen such as polysaccharides to create an effective vaccine against the vaccine. so when the preparation of sub unit and conjugate vaccine we use adjuvant? so what is the use of using an peptide in case of babies having week immune system?
Basically my question is What is the use of peptides when we are using adjuvants to enhance the immunogenic response?
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.
