Vaccines have curtailed the spread of several infectious diseases, such as smallpox, polio and measles. However, vaccines against some diseases, including HIV-1, influenza and malaria, don’t work very well, and one reason could be the timing of antigen and adjuvant presentation to the immune system. Now, researchers reporting in ACS Central Science developed an injectable hydrogel that allows sustained release of vaccine components, increasing the potency, quality and duration of immune responses in mice.
The researchers developed a polymer-nanoparticle hydrogel that could be mixed with vaccine components. When injected under the skin of mice, the material formed a localized area of inflammation that attracted certain types of immune cells, while slowly releasing the antigen and adjuvant over a period of several days. As a result, the mice injected with the hydrogel produced more antibodies over a longer period of time than mice treated with a traditional vaccine. Importantly, the antibodies produced by the hydrogel-vaccine-treated mice had about 1,000-fold higher affinity for the antigen than those made by mice receiving the standard immunization. Although the new system still needs to be tested to see if it improves vaccine protection from specific diseases, this study demonstrates a simple, effective vaccine delivery platform that enhances the potency and duration of antibody-mediated immunity in mice, the researchers say.