There has been a great deal of discussion about the use of adjuvants to improve the immunogenicity of vaccines against the 2009 H1N1 pandemic influenza strain. What effect do these compounds have on the immune response?
Adjuvants are compounds added to vaccines that stimulate the immune response. They are often used when the antigen is in short supply, or does not induce a good antibody response. Because the 2009 H1N1 pandemic influenza strains do not replicate well in eggs, it has been suggested that adjuvants be used to ensure that there is sufficient supply of vaccine.
A recent study demonstrates very clearly the effect of adjuvants on the immune response. Mice were immunized with egg-produced 2009 H1N1 influenza vaccine with or without the adjuvant MF59. A boost inoculation was given on day 21. Sera were taken on days 13 and 21 and the antibody response was measured by hemagglutination-inhibition (HI) assay. If you don’t know how an HI assay works, please read my previous description. The results of the assay are shown in the figure.
Dormitzer, PR, Rappuoli, R, Casini, F, Wack, A et al (2009). Adjuvant is necessary for a robust immune response to a single dose of H1N1 pandemic flu vaccine in mice PLoS Currents: Influenza