Tetravalent Abeta1-15 vaccine reduces TCR-positive cell infiltration and up-regulates p75 in Tg2576 brains compared to Abeta42 vaccine.

In order to investigate the effect of Abeta vaccines on T cell infiltration into the brain, we immunized Tg2576 mice with two adenovirus vaccines containing tetravalent Abeta1-15 (4xAbeta15) or Abeta42. TCR-positive cells were found in the ventricle, parenchyma, and surrounding the vasculature, especially concentrating in the periventricular parenchyma, the reticular part of the substantia nigra and the corpus striatum. Compared to the Abeta42 group, TCR-positive cells in the tetravalent (4x) Abeta15 group were significantly decreased. Both vaccines down-regulated neurotrophic and inflammatory factors, but the 4xAbeta15 vaccine up-regulated TrkA and p75 compared with the Abeta42 vaccine. The results suggest that the 4xAbeta15 vaccine might be safer and more beneficial than the Abeta42 vaccine.