Inhibition of fusion protein anti - CD19(Fab) - LDM on B - cell lymphoma

Objective To investigate the inhibition of the fusion protein anti-CD19(Fab)-LDM on B-cell lymphoma. Methods Using flow cytometry to analyze the in vitro immunological binding activity of anti- CD19 (Fab)- LDP antibody and B- cell lymphoma cells and its dissoci ation constant. The Raji cell xenograft model in Balb/c nude mice was established. The target position of Cy5-labeled anti-CD19 (Fab)- LDP in nude mice was determined by in vivo imaging. The fusion protein anti-CD19(Fab)-LDM was injected into Raji tumor-bearing nude mice through caudal vein. Its inhibition on tumor growth was determined, the inhibition rate was calculated, and the effect was evaluated. Results The affinity between anti-CD19 (Fab)- LDP antibody and the target antigen was similar with anti - CD19 (Fab) antibody, and the dissociation constants were 3.3×109M-1 and 4.3×109M -1, respectively. The subcutaneous Raji cell lymphoma xenograft model was successfully established. The findings of the in vivo imaging showed that the fusion protein anti- CD19(Fab)-LDP could be targeted to the tumor site.The fusion protein anti-CD19(Fab)-LDM could inhibit the growth of the transplanted CD19+ B cell lymphoma with dose dependency. Conclusion The fusion protein anti-CD19(Fab)-LDM, as an antibody-targeted drug, has significant and specific anti-tumor effect, which has a good application prospect in the treatment of B-cell lymphoma. Key words: Recombinant fusion proteins; Lymphoma, B - Celll; Antineoplastic agents; Targeted therapy; Xenograft model