The biochemical function of bivalent aptamer assemblies against B cell markers CD19 and CD20.

B cells, essential components of the adaptive immune system, are central to the pathology of B cell malignancies and autoimmune disorders. These cells can be specifically targeted using ligands that recognize B cell surface receptors such as CD19 and CD20. Utilizing ligand-guided selection (LIGS), a variation of the systematic evolution of ligands by exponential enrichment (SELEX) method, we previously identified high-affinity, high-specificity aptamers targeting CD19 and CD20. In this study, we report the functional characterization of dimeric aptamer assemblies designed to target CD19 and CD20 on B cell lymphomas, reinforcing the potential of LIGS-derived aptamers as versatile tools for targeting cell surface receptors. Functional studies in CD21-negative B cells using the most optimized dimeric aptamers revealed that the dimeric CD19 aptamers were selectively internalized, imitating the behavior of anti-CD19 antibodies. Additionally, dimeric CD20 aptamers exhibited enhanced antigen binding compared to their monomeric counterparts, without inducing calcium release. These findings underscore the promise of LIGS-generated aptamers as cost-effective, stable, and precise therapeutic agents for B cell-associated malignancies such as diffuse large B cell lymphoma (DLBCL), advancing the development of aptamer-based synthetic therapeutics with strong clinical potential.