mIL-10 (accession no. NP_034678) cDNA that was amplified with a pair of NotI-tagged primers, 5′-ACTTGCGGCCGCCAAAGTTCAATGCCTGGCTCAGCACTGCTATGCTGCCTG-3′ and 5′-ATCCGCGGCCGCGATAACTTTCACCCTAAGTTTTTCTTACTACG GTTAGCTTTTCATTTTGATCATCATGTATGCTTC-3′, was subcloned into the F gene-deleted site of the LitmusSalINheIhfrag-TSΔF carrying the SalI and NheI digested fragment containing M and HN genes from pSeV18+/TSΔF RG-7204 in LITMUS38 (NEB) . The
SalI and NheI digested fragment of pSeV18+Aβ1–43/TSΔF was substituted with the corresponding fragment of the mIL10 gene-introduced LitmusSalINheIhfrag-TSΔF. The cDNA of SeV18+LacZ/TSΔF (pSeV18+lacZ/TSΔF) was constructed in similar manner using an amplified fragment of LacZ . pSeV18+Aβ1–43/TSΔF-mIL10 or pSeV18+LacZ/TSΔF was transfected into 293T cells with T7-expressing plasmid. The T7-driven recombinant SeV18+Aβ1–43/TSΔF-mIL10 and SeV18+LacZ/TSΔF RNA genomes were encapsulated by NP, P, and L proteins, which were derived
from their respective co-transfected plasmids. The recovered SeV vectors were propagated using F protein-expressing packaging cell line . The virus titers were determined using infectivity and were expressed in cell infectious units (CIU). The SeV vectors were stored at −80 °C until use. rSeV was diluted with PBS to give 5 × 106 CIU/head in a final volume of 0.02 ml, and was administered once nasally or intramuscularly (left LEE011 in vitro quadriceps) to 12-month-old Tg2576 mice for analysis of cognitive functions and body weight, or to 24-month-old Tg2576 mice for evaluation of amyloid burdens and Aβ contents in the brain. Control Tg2576 mice received rSeV-LacZ and were
analyzed in the same way. Tg2576 mice received the vaccine nasally or intramuscularly at the age of 24 months and were sacrificed 8 weeks after by CO2 asphyxiation. Their brains were removed and cut in half sagittally. Anti-human Aβ antibody titers in the serum of nasally or intramuscularly vaccinated mice with rSeV-Aβ or rSeV-LacZ (n = 4 each) were quantified by a sandwich ELISA. Microtiter ELISA plates were coated GBA3 overnight at 4°C with 2 μg/ml of synthetic human Aβ1–42 in 0.1 M NaHCO3, pH 8.3, washed twice with washing buffer, blocked with 1% BSA and 2% normal goat serum in PBS for 2 h at room temperature (RT), washed twice and incubated with mouse serum samples diluted 1:500 in blocking buffer for 2 h at RT while shaking, washed × 4 and incubated horseradish peroxidase-conjugated goat-anti-mouse IgG for 2 h at RT, washed × 4 and analyzed colorimetrically after incubation with the chromogen substrate 3,3′,5,5′-tetramethylbenzidine (Kirkegaard & Perry Laboratories, Gaithersburg) at RT. Using highly specific antibodies and a sensitive sandwich ELISA, we quantified insoluble Aβ40 and Aβ42 in brain homogenates extracted with TBS, 2% SDS and 70% formic acid according to the method described .