[Immunization with recombinant HBcAg and ß-amyloid peptide fusion protein promotes clearance of intrahippocampally injected ß-amyloid peptide in rats].

OBJECTIVE: To study the effects of immunization with the fusion protein CAC (a product of prokaryotic expression of recombinant HBcAg and ß-amyloid peptide fusion gene) against the toxicity induced by intrahippocampal injection of aggregated ß-amyloid peptide (Aß) in rats. METHODS: SD rats were immunized intraperitoneally with the fusion protein CAC, and the titer of anti-Aß antibody was evaluated by ELISA. When the titers of the anti-Aß antibody reached 1:3 000, aggregated Aß was injected into the CA1 region of the rat hippocampus. Two weeks after Aß injection, the rats underwent morris water maze test before sacrificed to prepare the brain slices with Congo red and haematoxylin staining. RESULTS: The titer of anti-Aß antibody reached 1:3 000 after 5 immunizations with the fusion protein. After Aß injection, the saline-immunized rats showed a reduced cognitive behavior in the Morris water maze test compared to the CAC-immunized rats. In the saline-immunized rats, the neurons around the site of Aß injection exhibited obvious cell damages with Aß deposits and glial infiltration, whereas in CAC-immunized rats, Aß deposits were significantly reduced or even absent. CONCLUSION: Immunization with the fusion protein CAC can inhibit the toxicity induced by intrahippocampal aggregated Aß injection.