Improved Humoral Immunity and Protection Against Influenza Virus Infection With a 3D Porous Biomaterial Vaccine

The study developed an injectable immunization platform using a slurry of antigen-loaded hydrogel microparticles that form a porous scaffold for antigen uptake by immune cells. This platform was found to stimulate a strong cellular humoral immune response, with increased CD4+ T follicular helper (Tfh) cells and prolonged germinal center (GC) B cells, comparable to the commonly used adjuvant, aluminum hydroxide (Alum). By increasing the weight fraction of polymer material, the researchers enhanced material stiffness and further increased antigen-specific antibody titers, superior to Alum. When mice were vaccinated with inactivated influenza virus loaded into this more highly crosslinked formulation, it elicited a strong antibody response and provided better protection against a high dose viral challenge than Alum. This suggests that by tuning physical and chemical properties alone, we can enhance adjuvanticity and promote humoral immunity and protection against a pathogen.