The development of vaccines capable of generating an appropriate immune response remains a challenge for certain diseases. In this work we have prepared some microspheres with a biodegradable and biocompatible polymer, PLGA (poly (lactic-co-glycolic acid), which serve as a release and adjuvant system for synthetic peptides. We have used these microspheres containing beta-amyloid peptide (implicated in Alzheimer's disease) to develop a humoral immune response in mice after intranasal and subcutaneous administration. In addition we have been able to induce combined humoral and cellular responses in mice using model antigens.