Identification of Adjuvants that Enhance the Magnitude and Durability of Antibody Responses to a Nanoparticle-Based Malaria Vaccine

Abstract

To evaluate strategies for increasing vaccine efficacy, we assessed the ability of different classes of adjuvants to enhance vaccine-induced antibody responses to a Q{beta} bacteriophage virus-like particle (VLP)-based vaccine for malaria targeting the vulnerable L9 epitope from the circumsporozoite protein (CSP). From a panel of over a dozen adjuvants, five formulations significantly increased anti-CSP IgG titers and two also enhanced antibody durability. When assessed in a mouse malaria challenge model, immunization of mice with Q{beta} L9 VLPs plus either of two promising adjuvants, Cquim-MA and LQ, elicited sterilizing protection when mice were challenged soon after vaccination and also six months later. This study identifies promising adjuvants with different formulations that enhance both the magnitude of CSP-targeting antibodies and the longevity of VLP-induced immunity.