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Koski, J.

Publications and source records attributed to Koski, J..

2 recordsLinked to original sources
bioRxiv2026

Feeder cell - the key component in producing scalable and fit NK cells for therapeutic use

Natural killer (NK) cells are increasingly recognized as a versatile therapeutic platform, yet their translation is hindered by limited ex vivo proliferation. Feeder cells serve as robust stimulatory component supplying activating signals required to initiate large-scale NK cell expansion. Here, using bench-scale cultures, we evaluated how distinct engineered K562-based feeder cells influence NK cell proliferation, phenotype maintenance, potential for activation, and post-cryopreservation function. Across conditions, feeder-based systems consistently enabled superior, up to 500-fold higher NK cell yield compared to feeder-free system. Variants incorporating membrane-bound costimulatory and cytokine cues yielded the most favorable balance between expansion and functional preservation. Simple adjustments to cryopreservation, including high-density-freezing and centrifuge-free-thawing, further supported NK cell recovery. Together, these findings highlight feeder cells as essential upstream reagents for effective NK cell bioproduction and provide foundational biological insights to guide the rational design and validation of future scalable NK cell manufacturing platforms. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=200 SRC="FIGDIR/small/718880v1_ufig1.gif" ALT="Figure 1"> View larger version (74K): org.highwire.dtl.DTLVardef@1e8e8baorg.highwire.dtl.DTLVardef@720d4org.highwire.dtl.DTLVardef@1fc7ce2org.highwire.dtl.DTLVardef@16b0fca_HPS_FORMAT_FIGEXP M_FIG C_FIG

immunology↗
bioRxiv2026

Efficient NK cell transduction with VSV-G-pseudotyped lentiviral vectors

The need for safe, allogeneic cell therapies for cancer is driving a growing interest in CAR-NK-based therapies, which, unlike CAR-T cell therapies, offer the potential for off-the-shelf administration. Lentiviruses pseudotyped with vesicular stomatitis virus glycoprotein G (VSV-G) are commonly used for genetic modification of cell therapy products. Their use in NK cells, however, is limited by low transduction efficiency. This study explores the complexities of NK cell transduction using lentiviral vectors pseudotyped with VSV-G. We demonstrate that efficient transduction depends on multiple factors such as NK cell activation, construct design, lentivirus pseudotype selection, and the use of transduction enhancers. By optimizing these elements, we achieved effective transduction, facilitating the use of VSV-G-pseudotyped LVs for therapeutic NK cell production. Our optimized workflow comprises NK cell activation with interleukins, followed by transduction with a NK cell-specific CAR construct using VSV-G-pseudotyped LVs in the presence of BX795 and Retronectin, resulting in excellent transduction efficiency without compromising NK cell phenotype or growth. This allows for the use of a widely used gene transfer vector with an excellent safety record for producing therapeutic NK cell products.

immunology↗