Synergistic Enhancement of Humoral and Cellular Immunity in Attenuated Live Vaccines Using Chemical Nanoadjuvants: Evaluation of Sustained-Release Formulations.

Abstract

Achieving a balance between enhancing both humoral and cellular immunity while ensuring sustained release for attenuated live vaccines has long been a challenge in the vaccine industry. However, the incorporation of chemical materials as nanoadjuvants has emerged as a promising strategy to address this challenge. In this study, a novel nano-adjuvant with sustained release properties was developed by combining polyethylene glycol (PEG) and other biochemical and molecular biology agents with CpG. The efficacy of this adjuvant was assessed using the widely applied CSF attenuated live vaccine. The body temperature and relative daily weight gain results demonstrated the safety of the formulations. Importantly, the combination of CpG immune enhancers and sustained-release agents led to a synergistic augmentation of both humoral and cellular immune responses. Specifically, the combination of PEG20000 and benzoic acid, along with Seppic white oil, significantly enhanced humoral immunity. In contrast, the combination of total white oil, PEG6000 and benzoic acid demonstrated superior efficacy in promoting cellular immunity. This study offers important insights into enhancing vaccine efficacy through novel adjuvant combinations, which can be applied to the development of more effective vaccines in the future.