Luciferase Reporter Cell Line - HL60

Antibodies are undoubtedly the most versatile class of biologics with a wide range of applications in basic research, disease diagnosis and therapy. Researchers have developed a luciferase-based assay, called the Malibu-Glo Assay, for optimizing antigen-binding structural domains with desirable properties and enabling sensitive detection of tumor antigens. The assay involves a recombinant immunoconjugate, called the Malibu-Glo reagent, which includes immunoglobulin or non-immunoglobulin antigen-binding structural domains linked to the marine luciferase gene. The researchers produced the reagent as a secreted protein in mammalian cells, maintaining the functional activity of the antigen-binding structural domain and luciferase. By using the Luciferase Reporter Cell Line - HL60 cell line, the researchers were able to directly utilize the crude supernatant containing the secreted Malibu-Glo reagent for cell surface antigen detection, avoiding cumbersome protein purification and labeling steps. This method further demonstrated its utility in selecting single-chain antibody fragments (scFvs) with desirable affinity properties for use in chimeric antigen receptors (CARs). In conclusion, the Malibu-Glo Assay is a rapid, simple, sensitive, specific and cost-effective antigen detection method with multiple applications in the fields of antibody engineering, antibody humanization and CAR-T cell therapy.

Figure 1. The researchers replaced Nluc with Gluc, Tluc16, and Mluc7 to test the scalability of the Nluc-based Malibu-Glo assay. The ability of these fusion constructs to express CD19 on the cell surface was assessed using HL60 (CD19-negative acute myeloid leukemia cell line) as a negative control. The results showed that all CD19-scFv1-luc Malibu-Glo reagents exhibited specific binding in CD19-positive cell lines, while there was no significant binding in HL60. This demonstrates that the Malibu-Glo assay system maintains enzymatic activity and specific binding regardless of which marine fluorokinase is used. (Natarajan V, et al., 2020)