Effect and Potential Mechanism of Immunotherapy on Cognitive Deficits in Animal Models of Alzheimer's Disease: A Systematic Review and Meta-Analysis

•What is the primary question addressed by this study?This study explored whether different immunological approaches and animal models have an effect on the improvement of cognitive dysfunction in Alzheimer's disease (AD) and the potential mechanism of immunotherapy to ameliorate cognitive dysfunction in AD animal models?•What is the main finding of this study?Active and passive immunization could markedly ameliorate learning and memory impairment in 3 × Tg AD animal models, and active immunization could ameliorate the learning and memory ability of the APPswe/PS1ΔE9 AD animal model compared to the control group. Cognitive dysfunction was ameliorated by immunotherapy, which might mainly be via reducing Aβ40, Aβ42, and Tau levels, as well as increasing IL-4 levels.•What is the meaning of the finding?Immunotherapy may be a potential treatment to alleviate symptoms in animal models of AD. Meanwhile, this Systematic Review and Meta-Analysis may also provide theoretical insight into the clinical translation of immunotherapy.