Primary antibodies used in this study were: against Ab (1:50; Novocastra, Newcastle, UK), Ab40 (1:250; Chemicon), Ab42 (1:250; Chemicon), tau-2 (1:10,000; Sigma), b-APP (1:100; Chemicon), human leukocyte antigen DR (CR3/43; 1:400; Dako), IgG (1:1,000; Dako), IgM (1:1,000; Dako), C3 (1:1,000; Dako), CD3 (1:100; Novocastra), CD4 (1:10; Novocastra), CD8 (1:100; Novocastra), CD20 (1:400; Dako), CD45RO (1:50; Dako), CD68 (PGM1; 1:50; Dako) and CD79a (1:250; Dako). Bound primary antibody was visualized using a standard diaminobenzidine streptavidin-biotin horseradish peroxidase method (Dako).