University of Pennsylvania Jun 6 2025 In the quest to design vaccines that better help the body's immune system fight disease, scientists are always looking for more tools for their arsenal. The strong antibody responses generated by vaccines provide an important first round of defense, but "you always want to have a backup plan," says Biomedical Graduate Studies Ph.D. student Emily A. Aunins, considering viruses mutate to evade antibody responses that become widespread in a population. T cells,