Dr. Louisa Hope-Weeks Associate Professor Chemistry Aerosolized PLA and PLGA Nanoparticles Enhance Humoral, Mucosal and Cytokine Responses to Hepatitis B Vaccine Porous poly(L-lactic acid) (PLA) and poly(lacticco- glycolic acid) (PLGA) nanoparticles were tested for pulmonary delivery of Hepatitis B vaccine. In particular, the effects of particle size and hydrophobicity on mucosal and cell-mediated immune responses were investigated. Three formulations of PLA and PLGA nanoparticles containing a fixed amount of Hepatitis B surface antigen (HBsAg) were prepared by a double- emulsionsolvent-evaporation method and characterized for surface morphology, charge, size, density and in vitro release. The immune responses were studied by measuring secretory IgA levels in mucosal fluids and quantitating cytokine levels in rat spleen homogenates. This study demonstrates that inhalable nanoparticles of HBsAg produce an enhancement of immune responses.