Immunotherapeutic effects of lymphocytes co-cultured with human cord blood-derived multipotent stem cells transplantation on APP/PS1 mice.

Alzheimer's disease (AD) is an inexorable neurodegenerative disease that involves neuroinflammation in the brain, in addition to abnormal accumulation of amyloid-β (Aβ) and hyperphosphorylated tau. Evidence shows that human cord blood-derived multipotent stem cells (CB-SCs) can modulate autoimmune responses by altering regulatory T cells (Tregs). Our previous study found that CB-SCs could regulate the peripheral immune system of AD patients in vitro, mainly increasing the proportion of Tregs and anti-inflammatory cytokines. To further investigate the effects of lymphocytes co-cultured with CB-SCs on AD, the APP/PS1 mice received monthly transplants of lymphocytes co-cultured with CB-SCs for 4 months. Then, the ethological and biochemical experiments were conducted. We found that APP/PS1 mice injected with lymphocytes co-cultured with CB-SCs showed improved spatial learning, which significantly correlated with fewer Aβ plaques in brain. The present study also indicated that lymphocytes co-cultured with CB-SCs could promote the protective and reparative cytokines in the peripheral blood and brain to alleviate neuroinflammation in AD mice. These findings conclude that the systemic transplantation of lymphocytes co-cultured with CB-SCs can improve cognitive and pathological impairment of APP/PS1 mice via an immunomodulatory effect.