Objective of this proposal is to engineer a Powder-Laden, Dissolvable MicroNeedle Array (PLD-MNA) to improve newborn Hib vaccination. Due to the immature immune system, most of the newborn vaccines induce suboptimal immune responses and require multiple boosters to induce a protective immunity. The lengthened vaccination schedule, in conjunction with a rapid decline of maternal antibodies after birth, leaves a few months of a vulnerability period to various infections for every newborn, which is the single major factor for a high rate of vaccine- preventable diseases occurring in newborns. To eliminate or greatly shorten the vulnerable period, we identified a potent adjuvant cGAMP, an agonist of the stimulator of IFN genes (STING) that could robustly bolster adaptive immune responses in neonatal mice. We will combine this potent adjuvant and powder-based epidermic vaccination to vigorously augment Hib vaccine and reduce Hib vaccine dosage from the current 4 to 2 doses in this proposal. We will first fabricate PLD-MNA encapsulated with Hib conjugated PRP-T vaccine and cGAMP and characterize its loading capacity and delivery efficiency in both newborn mice and piglets. We will also minimize skin irritation, if there is any, in a piglet model and optimize the dosage of immunization in newborn mice.
Aim 2 will validate whether prime at birth and boost 10 days later with PLD-MNA packaged with PRP-T/cGAMP can induce a comparable or superior immune response than four alum/intramuscular immunizations of PRP-T vaccine in the presence of maternal antibodies. This needle-free, potentially home-use vaccination, if successful, would represent a paradigm-shifting technology to augment many vaccines for newborns and infants, because most of current infant vaccines are made in a form of powder and can be directly loaded into the PLD-MNAs and applied to newborns.
The proposal aims at development of a novel technology to deliver powdered Hib vaccines into the epidermis of the newborns. This safe, sufficient, and minimal invasive vaccination strategy could potentially reduce the vaccination dosage and eliminate the vulnerable time to Hib infection for newborns before a significant decline of maternal antibody.