Escherichia coli bacteria.Wikimedia, Eric Erbe and Christopher Pooley of USDA.Vaccines were created to protect us from pathogens ranging from influenza and measles to smallpox, polio, and diphtheria. But vaccines to some pathogens—like HIV and the herpes simplex virus (HSV)—have repeatedly failed in clinical trials. In the lone successful HIV vaccine trial to date, the vaccine only provided slight protection over the placebo. And GlaxoSmithKline (GSK) reported last year that its promising HSV2 vaccine against genital herpes sputtered in a large, late-stage trial.
Most vaccines provide the immune system with key pathogen-derived molecules to help it later recognize and attack the same intruder. But many of the molecules are, by themselves, “not really capable of provoking strong immune responses,” explained Dennis Klinman, an immunologist at the National Cancer Institute.
One way to boost the effectiveness of a vaccine is to include adjuvants—extra ingredients that prompt the immune system to take notice and elicit protection. The most commonly used adjuvants, first approved for human use almost 80 years ago, are aluminum-based salts (alum salts), usually aluminum hydroxide or aluminum phosphate. But alum salts only effectively rouse certain types of immune cells. T cells that recognize and kill infect cells—important in clearing infections—are not well stimulated by alum.
Now, scientists ...
