Figure 1. A. Flow cytometry analysis with anti-BCMA ( DM4) on K562-BCMA (Red histogram) (K562 cells stably transduced by human BCMA full length gene) and K562 (Negative control cell line) (Blue histogram).? B. Flow cytometry data of serially titrated anti-BCMA ( DM4). The Y-axis represents the mean fluorescence intensity (MFI) while the X-axis represents the concentration of IgG used.

Figure 2.? A. Flow cytometry analysis with anti-BCMA ( DM4) on NCI-H929 cells (Red histogram) or rabbit control antibody on NCI-H929 cells (Blue histogram). ?B. Flow cytometry data of serially titrated anti-BCMA ( DM4) on NCI-H929 cells. The Y-axis represents the mean fluorescence intensity (MFI) while the X-axis represents the concentration of IgG used.

Figure 3.?Phylogenetic analysis of different Anti-BCMA DimAb clones.A) heavy chain and?B) Light chain.

Figure 4. Affinity ranking of different DimAb clones by titration of rabbit DimAb antibody concentration onto K562-BCMA or NCI-H929 cells. Different concentrations of various anti-BCMA DimAb clones were incubated with K562-BCMA ( A) or NCI-H929 cells ( B) at 4℃. Bound rabbit IgG was detected in flow cytometry analysis. The Y-axis represents the mean fluorescence intensity (MFI) while the X-axis represents the concentration of IgG used.

Figure 5. ELISA plate was coated with recombinant BCMA-hFc fusion protein PME100001 , followed by pre-blocking with? huC11D5.3?antibody ( Grey bar) or rabbit control IgG ( Black bar), and then different rabbit DimAbs antibodies?were added to check the competitive inhibition of? huC11D5.3. DM3 clone exhibits the strongest inhibition ( Red bar). This data indicated that DM3 bind to the same epitope as bb2121.

Figure 6. Immunoprecipitation analysis. Cellular overexpression lysates (made from HEK293F cells transfected with FLAG tagged human BCMA full length gene) were pre-incubated with 6 different rabbit DimAb clones and negative control IgG. The immunocomplexes were further pulled down by protein A beads, fractionated, and blotted with mouse anti-FLAG monoclonal antibody.

Figure 7. Western blot analysis of BCMA protein using Anti-BCMA antibody (Cat. DME100004) at 1:1000 dilution.
Secondary antibody: HRP Goat Anti-Rabbit IgG (H L) at 1:5000 dilution.
1. K562 cell lysate (negative control); 2. K562 cell lysate with overexpressed human BCMA proteins; 3. MM.1S cell lysate (native BCMA protein)

Figure 8. Flow cytometry analysis of antigen binding of rabbit anti-human BCMA mAb(DME100004).

(A) DME100004 does not bind to Jurkat cells that do not express BCMA.
(B) A clear peak shift of DME100004 was seen compared to the control when incubated with BCMA-expressing MM.1S cells, indicating strong binding of DME100004 to BCMA. Antibodies were incubated at 2 μg/mL.