Abstract 5656: Next-level efficiency: StraightFrom Spleen Isolation Kits - standardizing isolation of untouched B cells with minimal hands-on time

The study of mouse B cells is essential for advancing our understanding of the immune system, developing new vaccines, and driving progress in immunotherapy through the discovery of new targets. Mouse B cells are abundant in the spleen, one of the major lymphoid organs, making splenic isolation a critical step in B cell research. General workflow to isolate these cells relies on manual mechanical disruption of the mouse spleen and subsequent magnetic purification. However, this combination of methods is time-consuming and operator dependent, with important implication for reproducibility and major impact on downstream application. To address this gap, we at Miltenyi have developed the StraightFromSpleen kit, an all-in-one solution for isolation of highly pure murine B cells from mouse spleen. Briefly, we used the GentleMACS dissociator to disrupt the spleen while labeling unwanted cells with an antibody cocktail. We then performed automated magnetic labeling of cells and isolation of untouched B cells and Pan B cells using the autoMACS NEO Separator. After separation, we measured purity, viability and yield and compared these results with those obtained using a standard isolation kit. Finally, we tested the functionality of the isolated B cells and Pan B cells by culturing then with LPS or in presence of anti-CD40 antibody and IL-4, to promote proliferation, IgG class-switch and differentiation to antibody secreting cells. We demonstrated that the newly developed StraigthFrom Spleen kits allow for isolation of highly viable and pure B cells. Isolated B cells efficiently proliferated in vitro, differentiate to CD138+ antibody secreting cells and were able to class-switch. In conclusion, we have developed a simple, fast, and reliable cell isolation method that significantly accelerates the isolation of functional B cells. This represents an attractive alternative to the laborious multi-step protocols commonly used in academic and industrial laboratories and has the potential to set a new standard for the B cell field. Citation Format: Sebastian Flade, Amelie Borczewski, Stefano Vergani, Gregor Winkels, Anna Baranska, Anne Richter. Next-level efficiency: StraightFrom Spleen Isolation Kits - standardizing isolation of untouched B cells with minimal hands-on time [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5656.