Leukoreduction filter derived NK cells offer a promising source for off the shelf CAR NK cell immunotherapy

Immunotherapy employing natural killer (NK) cells has emerged as a transformative approach to treating hematological malignancies. The reprogramming of NK cells by incorporating a chimeric antigen receptor (CAR) equipped with potent signaling domains has demonstrated efficacy in enhancing NK cell responses and improving specificity in recognizing cancerous cells. Despite these advancements, the primary challenge in implementing allogeneic NK cell therapy requiring a viable donor source for clinically relevant doses remains unresolved. This study tested NK cells obtained from leukoreduction filters (LRF) post-blood donation to address the need for an efficient and scalable supply of NK cells for generating anti-BCMA CAR NK cells. LRF-NK cells were isolated under sterile conditions and compared with peripheral blood (PB)-derived NK cells in terms of immunophenotype, proliferation capacity, and functional characteristics. Notably, no significant differences in inherent characteristics were observed between LRF-NK and PB-NK cells. Subsequently, both NK cell populations were employed to generate anti-BCMA CAR-NK cells. The data revealed a high specific cytotoxicity of Anti-BCMA CAR LRF-NK cells during co-culture with U266-B1 cells (70.3 ± 4.78%), surpassing that observed with CCRF-CEM cells (31.3 ± 2.35%) and similar to Anti-BCMA CAR PB-NK cells. Furthermore, the expression of IFN-γ and Granzyme B, following the co-culture of Anti-BCMA CAR LRF-NK cells with target cells, mirrored that observed in Anti-BCMA CAR PB-NK cells. This study provides the rationale and feasibility of utilizing LRF-NK cells as a safe, high-yield, accessible, and optimal cost-effective source for cancer immunotherapy.