Vaccines combined with adjuvant systems have been proven to enhance immunogenicity(Perrie et al. 2008).

What is an adjuvant?
An adjuvant as an agent that can stimulate an immune system while having few if any direct effects when given by itself.

What do adjuvants do?
The role of an adjuvant is to provide protection by preventing the antigen from degrading and also to make it easier for antigen-presenting cells to locate and engulf antigens(Perrie et al. 2008).

How do they do this?
Adujuvants stimulate the immune system to respond to the vaccine more vigourously, thus providing increased immunity to a particular disease.
They mimic specific sets of conserved molecules called PAMPs, which include:
- liposomes
- lipopolysaccharide (LPS)
- molecular cages for antigens
- components of bacterial cell walls
- endocytosed nucleic acids (such as double-stranded RNA (dsRNA))
- single-stranded DNA (ssDNA)
- unmethylated DpG dinucleotide - containing DNA
An adjuvant with a vaccine can greatly increase the immune response to the antigen by augmenting the activities of dendritic cells(DCs), lymphocytes, and macrophages by mimicking a natural infection.

What adjuvants are used?
Aluminum salts - these are the most common adjuvants used in vaccines for humans.
Organic adjuvants - these are most commonly used in animal vaccines.
Oil-based adjuvants - these are most commonly used in veterinary vaccines.
Virosomes - these are adjuvants with carrier systems (Clements 2002).

Factors effecting immunogenicity
Autoimmune disorders : Ultraviolet radiation Immunosuppression: Adjuvants
Contributed by Sidharsha Naidoo