Figure 1.

Determination of specificity of the BAC2 monoclonal antibody for CEACAM7 by FACScan analyses. Stable transfectants expressing individual CEA family members were incubated with BAC2 to determine its specificity. Stable transfectants expressing CEACAM1, CEACAM4, and CEACAM7 are CHO cells and CEA, CEACAM3, CEACAM6, CEACAM8, and a recombinant membrane-bound PSG1 are HeLa cells. As negative controls, the parental CHO-K1 and HeLa-neo cells were both negative with all antibodies (not shown). For each transfectant, an isotype-matched murine IgG was also included as a negative control, and the mean fluorescence values (ranging from 2 to 10), were subtracted from the values obtained with BAC2 or the positive control antibodies. The D14HD11 antibody was used as a positive control for the CEA, CEACAM1, CEACAM3, CEACAM4, and CEACAM6 transfectants, 80H3 was used for CEACAM8, BAP1 was used for the PSG1 transfectant, and CAC2 was used for CEACAM7. The ratio of the mean fluorescences obtained with BAC2 and the respective positive control antibody (×100) was calculated (relative reactivity). The mean fluorescence values of the control antibodies were between 260 and 880.