Gene Information:

• CD3: Encoded by CD3E, D, G; part of the Ig superfamily. It forms the essential signaling backbone of the T-cell receptor (TCR) complex. CD19: is a transmembrane glycoprotein. It belongs to the immunoglobulin superfamily and plays a critical role in B-cell development, activation, and maintenance throughout the immune system. 
• BCMA: Encoded by the TNFRSF17 gene, a critical member of the tumor necrosis factor receptor (TNFR) superfamily.

Protein Expression:

• CD3: Constitutive and universal marker for all mature T cells (CD4+, CD8+). Always present on the cell surface. CD19: is expressed almost exclusively on B-lineage cells, beginning at the early B-cell stage and persisting through mature B cells. Its expression is typically absent or markedly reduced in plasma cells. BCMA: It is a B-cell maturation antigen, whose expression is highly in mature plasma cells and nearly all multiple myeloma cells.

In vivo B-cell depletion by anti-human CD3/BCMA or anti-human CD3/CD19 bispecific antibodies (BsAbs) in B-hCD3EDG/hCD19/hBCMA mice.​ Bispecific antibodies (BMK1 and BMK2: targeting BCMA/CD3; BMK3: targeting CD19/CD3) or PBS control were administered as a single dose to B-hCD3EDG/hCD19/hBCMA mice (n=3 per group). Blood cells were harvested on day 1 and day 7 post-treatment. The frequency and absolute numbers of mCD45⁺ cells, B cells, and T cells were quantified by flow cytometry. Data are presented as mean ± SEM and analyzed by one-way ANOVA followed by Dunnett’s multiple comparisons test versus the PBS control group (*p<0.05, **p<0.01, ***p<0.001,****p<0.0001). This study was conducted in collaboration with our partner.

In vivo B-cell depletion by anti-human CD3/BCMA or anti-human CD3/CD19 bispecific antibodies (BsAbs) in B-hCD3EDG/hCD19/hBCMA mice.​ Bispecific antibodies (BMK1 and BMK2: targeting BCMA/CD3; BMK3: targeting CD19/CD3) or PBS control were administered as a single dose to B-hCD3EDG/hCD19/hBCMA mice (n=3 per group). Spleens were harvested on day 7 post-treatment. The frequency and absolute numbers of mCD45⁺ cells, B cells, T cells, plasma cells, and plasmablasts were quantified by flow cytometry. Data are presented as mean ± SEM and analyzed by one-way ANOVA followed by Dunnett’s multiple comparisons test versus the PBS control group (*p<0.05, **p<0.01, ***p<0.001,****p<0.0001). This study was conducted in collaboration with our partner.