IL-2(Shanghai Xinshengyuan Biological Medicine Co. Ltd.)

Adoptive immunotherapy represents a promising treatment for multiple myeloma (MM), relying on the availability of sustainable tumor-specific cytotoxic T cells. This study generated potent ex vivo expanded and activated marrow-infiltrating lymphocytes (eMILs) from MM patients and evaluated their immunologic characteristics and cytotoxic potential. MILs were expanded using anti-CD3/CD28 beads in the presence of IL-2, IL-7, and IL-15. The expansion rate, proportions of effector cells (including CD4⁺T cells, CD8⁺T cells, natural killer cells, and memory T cells), and the functional capacity of eMILs were assessed over 2 weeks of culture. Co-culturing MILs with anti-CD3/CD28 beads and cytokines resulted in substantial expansion and activation of MILs during the 14-day culture period. The eMILs displayed an increased proportion of CD8⁺T cells and a high prevalence of central memory T cells (Tcm; > 80 %), with minimal presence of myeloid-derived suppressor cells or regulatory T cells. Compared to expanded peripheral blood lymphocytes, eMILs demonstrated potent cytotoxicity against target MM cells, particularly CD138⁺ primary MM cells from autologous patients. These findings suggest that MILs derived from the bone marrow (BM) of MM patients can be expanded and activated to exhibit enhanced antigen specificity for CD138⁺ MM cells. Furthermore, eMILs may induce sustained cytotoxic effects due to their high proportion of Tcms. In conclusion, as a unique subset of T cells shaped by the BM microenvironment, MILs show promise as a novel immunotherapeutic approach for MM.

IL-2 is a potent cytokine that promotes multiple immune cells proliferation and activation. Accordingly, IL-2 based immunotherapies are emerging to treat cancers or AIDS by enhancing T cell growth and function. Besides, IL-2 is indispensable in in vitro cultivation of immune cells which is a critical step of CAR-T or CAR-NK immunotherapies. In bulk manufacturing of recombinant IL-2, E. coli expression system has several advantages such as low cost and rapid growth. However, high level protein expression in prokaryotic organisms often results in inactive insoluble aggregates, also known as inclusion bodies. It is crucial and most challenging work to solubilize and refold the protein of interest from inclusion bodies to generate its bioactive form. While multiple spectrum method had been applied to monitor the refolding process, the question of how to measure the refolding efficiency from the perspective of its biological function remained unaddressed. Here we present a receptor-based sandwich ELISA method to evaluate the bioactive product in samples and provide a guidance for manufacturing bioactive rhIL-2 (recombinant human IL-2) with prokaryotic expression system. Compared to traditional antibody-based ELISA method, this novel approach truly measures the presence of functional rhIL-2 and also potentially allows the detection of rhIL-2 variants with modifications like PEGylation as it doesn't rely on the exact amino acid sequence.