IL4 and susceptibility to pneumonia measurement: A bivalent DNA vaccine containing OprF and PcrV epitopes, delivered with a polyaspartamide/polyethylene glycol di-aldehyde (PSIH/PEG DA) hydrogel, allowed controlled antigen release, higher specific IgG titers and cytokine levels (INF-γ, IL-4, TNF-α, IL-2, and IL-17), and improved survival rate (83%) with reduced bacterial loads and inflammation in a pneumonia model [232].