Characterization of murine CEACAM1 in vivo reveals low expression on CD8(+) T cells and no tumor growth modulating activity by anti-CEACAM1 mAb CC1

McLeod, Robbie L.; Angagaw, Minilik H.; Baral, Toya Nath; Liu, Liming; Moniz, Raymond Joseph; Laskey, Jason; Hsieh, SuChun; Lee, Mike; Han, Jin-Hwan; Issafras, Hassan; Javaid, Sarah; Loboda, Andrey; Sadekova, Svetlana; O'Connor, Joann A.; Tse, Archie; Punnonen, Juha

For the evaluation of the effect of CC1 antibody on homophilic CEACAM1 interaction, the ELISA and cELISA assays used were similar as described above with some modifications. For ELISA, coating and blocking were performed the same way as above. Afterwards, 50 µl of a 1:3 serially diluted solution of CC1 antibody (starting at 20 µg/ml) or isotype control were added to the microtiter plates. After a 30 min incubation at room temperature, 50 ul of mCEACAM-hFc (Sino Biologics) at 1 µg/ ml was added and incubated for another 30 mins. Next, plates were washed three times with washing buffer as above and bound mCEACAM1-hFc was detected using a horseradish peroxidase-conjugated goat anti-human IgG (Jackson ImmunoResearch) as described above. For cELISA, a similar protocol was used except that mCEACAM1-hFc was used at 10 µg/ml and all other steps were performed the same way as for the ELISA assay.