All animal experiments were carried out in accordance with protocols approved by the Animal Care and Use Committee of the Kyoto University Graduate School of Medicine. Human rMFG-E8 (12 pmol in 300 μL of PBS containing 2.5% serum from C57BL/6 mice) was intravenously administered into 8-wk-old C57BL/6 female mice through the tail vein. Serum was harvested 15, 30, and 60 min after the injection, and the MFG-E8 level was measured by an indirect sandwich ELISA. In brief, a 96-well Maxisorp plate (Nalge NVP-AUY922 Nunc International) was coated with 1 μg/well of anti-FLAG mAb in 50 mM sodium bicarbonate buffer

(pH 9.6) and incubated with Reagent Diluent Concentrate 2 (R&D Systems). Triton X-100 was added to the serum samples at a final concentration of 1%, the samples were diluted ten times with TBS, and a 50-μL aliquot was applied to each well. After a 1-h incubation,

the wells were washed with wash buffer supplied with check details the Ampli Q kit (Dako), incubated with 0.8 μg/mL biotinylated hamster mAb against human MFG-E8 (clone 2–8E4A)15, washed as above, and incubated with 8000-times-diluted alkaline phosphatase-conjugated streptavidin (Dako) for 30 min. The alkaline phosphatase activity was measured using the Ampli Q kit. Human rMFG-E8 diluted with 10% normal mouse serum was used to prepare the standard curve. C57BL/6 female mice at the age of 10 wk were treated weekly with 12 pmol of hMFG-E8 for a total of four or six times, and sera were collected before, and 6 and 7 wk after the first injection. The concentration of anti-cardiolipin antibody in the sera was measured by ELISA. In brief, TCL 1 μg of cardiolipin in 100 μL of methanol was added to a 96-well plate (Immulon 1B microtiter plate; Thermo Labsystems), and the plate was air-dried. After blocking with 10% FCS, serially diluted mouse serum was added to the wells. After a 1-h incubation at room temperature, the mouse antibodies bound to the plate were detected using HRP-conjugated goat anti-mouse Ig (Dako) and peroxidase-detecting kit (Sumitomo Bakelite). The color reaction was read at 492 nm using a microplate reader (Titertek Instruments), and the titer of the antibody

was defined as the dilution that gave the absorbance of 0.1. Anti-nuclear antibody was detected by indirect immunofluorescence. In brief, human HEp-2 cells cultured on a glass slide were fixed with cold acetone and incubated with 50-times-diluted mouse serum at 37°C for 30 min. The antibodies bound to the HEp-2 cells were detected by Cy3-conjugated F(ab’)2 of goat anti-mouse IgG (Jackson ImmunoResearch Laboratories) diluted 100 times with PBS/10% normal goat serum, and observed by fluorescence microscopy (Biorevo, Keyence). The authors thank M. Fujii and M. Harayama for secretarial assistance. This work was supported in part by Grants-in-Aid for Specially Promoted Research from the Ministry of Education, Science, Sports, and Culture in Japan to S. N. H. Y.