Biology subjects

Paavilainen, H.

Publications and source records attributed to Paavilainen, H..

3 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↗

bioRxiv2018

HSV-1 strains circulating in Finland demonstrate uncoupling of geographic and phenotypic variation

A majority of adults in Finland are seropositive carriers of herpes simplex viruses (HSV). Infection occurs at epithelial or mucosal surfaces, after which virions enter innervating nerve endings, eventually establishing lifelong infection in neurons of the sensory or autonomic nervous system. Recent data have highlighted the genetic diversity of HSV-1 strains, and demonstrated apparent geographic patterns in strain similarity. Though multiple HSV-1 genomes have been sequenced from Europe to date, there is a lack of sequenced genomes from Nordic countries. Finlands history includes at least two major waves of human migration, suggesting the potential for diverse viruses to persist in the population. Here we used HSV-1 clinical isolates from Finland to test the relationship between viral phylogeny, genetic variation, and phenotypic characteristics. We found that Finnish HSV-1 isolates separated into two distinct phylogenetic groups, potentially reflecting historical waves of human (and viral) migration into Finland. Each HSV-1 isolate harbored a distinct set of phenotypes in cell culture, including differences in virus production, extracellular virus release, and cell-type-specific fitness. Importantly, the phylogenetic clusters were not predictive of any detectable pattern in phenotypic differences, demonstrating that whole-genome relatedness is not a proxy for overall viral phenotype. Instead, we highlight specific gene-level differences that may contribute to observed phenotypic differences, and we note that strains from different phylogenetic groups contain the same genetic variations.\n\nImportanceHerpes simplex viruses (HSV) infect a majority of adults. Recent data have highlighted the genetic diversity of HSV-1 strains, and demonstrated apparent genomic relatedness between strains from the same geographic region. We use HSV-1 clinical isolates from Finland to test the relationship between viral genomic and geographic relationships, differences in specific genes, and characteristics of viral infection. We found that viral isolates from Finland separated into two distinct groups of genomic and geographic relatedness, potentially reflecting historical patterns of human and viral migration into Finland. These Finland HSV-1 isolates had distinct infection characteristics in multiple cell types tested, which were specific to each isolate and did not group according to genomic and geographic relatedness. This demonstrates that HSV-1 strain differences in specific characteristics of infection are set by a combination of host cell type and specific viral gene-level differences.

microbiology↗