U266B1

U266B1, also referred to as U-266, is an established human multiple myeloma cell line. It was originally derived from the peripheral blood of a 53-year-old male patient with IgE-producing myeloma. As their name suggests, U266B1 cells are lymphoblast-like in morphology. They proliferate almost exclusively in suspension with minimal attachment to substrata. These cells secrete the cytokine interleukin-6 (IL-6) and immunoglobulin E (IgE) with λ light chains. These cells express classic plasma cell-associated antigens, including CD38, CD44, CD56, syndecan-1 (CD138) and BCMA, while they do not express classical B-cell antigens, such as CD19 and CD20.

Functionally, U266B1 cells exhibit autocrine signaling through IL-6, as these cells grow without exogenous IL-6. The doubling time of these cells has been reported to be approximately 55-144 hours depending on culture conditions. These cells are tumorigenic in vivo, as they engraft and proliferate in immunocompromised mice in either the bone marrow compartment (when given systemically) or as subcutaneous xenografts. The U266B1 cell line is used in multiple myeloma research to model malignant plasma cell biology, IL-6-mediated growth and survival, mechanisms of drug resistance and tumor-microenvironment interactions. U266B1 has also been used as a fusion partner to produce human monoclonal antibodies using hybridoma technology.