David Martinez is examining the quirks of the human immune system that make our antibody responses to dengue virus infection so different from the defenses mounted against its cousins, which include Zika virus, yellow fever virus, and West Nile virus. When people infected with dengue virus later become infected with a second variant of the virus, they can experience severe, sometimes hemorrhagic reactions. Martinez ultimately wants to understand how the immune mechanisms causing these reactions can be exploited to prevent or cure viral disease.