PT - JOURNAL ARTICLE AU - Emad I Wafa AU - Sean M Geary AU - Kathleen A Ross AU - Jonathon T Goodman AU - Balaji Narasimhan AU - Aliasger K Salem TI - Single dose of polyanhydride particle-based vaccine generates potent antigen-specific antitumor immune responses AID - 10.1124/jpet.118.252809 DP - 2018 Jan 01 TA - Journal of Pharmacology and Experimental Therapeutics PG - jpet.118.252809 4099 - http://jpet.aspetjournals.org/content/early/2018/10/25/jpet.118.252809.short 4100 - http://jpet.aspetjournals.org/content/early/2018/10/25/jpet.118.252809.full AB - There are many factors affecting vaccine efficacy. One of the most salient of these is the frequency and intervals of vaccine administration. In this study, vaccine administration modality for a recently reported polyanhydride-based vaccine formulation, shown to generate antitumor activity, was assessed. Polyanhydride particles encapsulating ovalbumin (OVA) were prepared using a double emulsion technique and subcutaneously delivered to mice either as a single dose or as prime-boost vaccine regimens where two different time intervals between prime and boost were assessed (7 or 21 days). This was followed by measuring cellular and humoral immune responses, and subsequently challenging the mice with a lethal dose of E.G7-OVA cells to evaluate tumor protection. Interestingly, a single dose of the polyanhydride particle-based formulation induced sustained OVA-specific cellular immune responses just as effectively as the prime-boost regimens. In addition, mice receiving a single dose vaccine had a similar level of protection against tumor challenge compared to mice administered prime-boosts. In contrast, measurements of OVA-specific IgG antibody titers indicated that a booster dose was required to stimulate strong humoral immune responses since it was observed that mice administered with a prime-boost vaccine had significantly higher OVA-specific IgG1 serum titers than mice administered with a single dose. These findings indicate that the requirement for a booster dose using these particles appears unnecessary for the generation of effective cellular immunity, and furthermore, that the generation of a strong IgG response to a tumor antigen not expressed on the tumor cell surface may not be important for antitumor potency.