Immuno-enhancing Effects of Adjuvants and how to measure?

·         Adjuvants may exert their immune-enhancing effects according to five immune-functional activities:

1.    Help in the translocation of antigens to the lymph nodes where they can be recognized by T cells,

a matter that leads to greater T cell activity with a heightened clearance of pathogen from the body.

2.    Provide physical protection to antigens which grants the antigen a prolonged delivery.                                                                                               The organism will be exposed to the antigen for a longer duration, making the immune system more robust.( Strong)

3.    Help to increase the capacity to cause local reactions at the injection site during vaccination,  greater release of danger signals by chemokine-releasing cells  like helper T cells and Mast cells.

4.    Induce the release of inflammatory cytokines which helps to not only recruit B and T cells at sites of infection, but also to increase transcriptional events leading to a net increase of immune cells as a whole.

5.    Increase the innate immune response to antigen by interacting with pattern recognition receptors (PRRs),specifically Toll-like receptors (TLRs), on accessory cells.

Method/ Criteria for evaluation of Adjuvant as immune-enhancing includes:

Adjuvant should be meet the following

q  Induces both antibody and CTL responses.

q   In animal models and humans.

q   Long lasting responses.

q   Dose sparing capability.

q   Good safety profile in humans.

q   Industrialized.

Ideally, adjuvants should strongly stimulate B- and T- cell immunity ,

while avoiding the excess innate immune system activation and,

 inflammatory cytokine production that mediates adjuvant reactogenicity.