Elisabeth Gyllensten Bjørnsen

• Bjørnsen, Elisabeth Gyllensten; Thiruchelvam-Kyle, Lavanya; Hoelsbrekken, Sigurd Erik; Henden, Camilla; Sæther, Per Christian & Boysen, Preben [Show all 8 contributors for this article] (2019). B7H6 is a functional ligand for NKp30 in rat and cattle and determines NKp30 reactivity toward human cancer cell lines. European Journal of Immunology. ISSN 0014-2980. 49(1), p. 54–65. doi: 10.1002/eji.201847746. Full text in Research Archive Show summary

  NK cells kill cancer cells and infected cells upon activation by cell surface receptors. Human NKp30 is an activating receptor expressed by all mature NK cells. The B7 family member B7H6 has been identified as one ligand for NKp30. Several alternative ligands have also been reported, and the field remains unsettled. To this end, we have identified full‐length functional B7H6 orthologs in rat and cattle, demonstrated by phylogenetic analysis and transfection experiments. In cell–cell contact‐dependent assays, chimeric NKp30 reporter cells responded strongly to B7H6 in rat and cattle. Likewise, rat NKp30 expressing target cells induced strong activation of B7H6 reporter cells. Together, these observations demonstrate that B7H6 is conserved as a functional ligand for NKp30 in mammalian species separated by more than 100 million years of evolution. B7H6 and NKp30 are pseudogenes in laboratory mice. The rat thus represents an attractive experimental animal model to study the NKp30‐B7H6 interaction in vivo. B7H6 was widely expressed among human cancer cell lines, and the expression level correlated strongly with the activation of human NKp30 reporter cells. Furthermore, siRNA knockdown of B7H6 abolished NKp30 reporter responses, suggesting that B7H6 is the major functionally relevant expressed ligand for NKp30 on these cancer cell lines.

• Knutsen, Linn Emilie; Dissen, Erik; Sæther, Per Christian; Bjørnsen, Elisabeth Gyllensten; Pialek, Jaroslav & Storset, Anne [Show all 7 contributors for this article] (2018). Evidence of functional Cd94 polymorphism in a free-living house mouse population. Immunogenetics. ISSN 0093-7711. p. 1–13. doi: 10.1007/s00251-018-01100-x. Show summary

  The CD94 receptor, expressed on natural killer (NK) and CD8+ T cells, is known as a relatively non-polymorphic receptor with orthologues in humans, other primates, cattle, and rodents. In the house mouse (Mus musculus), a single allele is highly conserved among laboratory strains, and reports of allelic variation in lab- or wild-living mice are lacking, except for deficiency in one lab strain (DBA/2J). The non-classical MHC-I molecule Qa-1b is the ligand for mouse CD94/NKG2A, presenting alternative non-americ fragment of leader peptides (Qa-1 determinant modifier (Qdm)) from classical MHC-I molecules. Here, we report a novel allele identified in free-living house mice captured in Norway, living among individuals carrying the canonical Cd94 allele. The novel Cd94LocA allele encodes 12 amino acid substitutions in the extracellular lectin-like domain. Flow cytometric analysis of primary NK cells and transfected cells indicates that the substitutions prevent binding of CD94 mAb and Qa-1b/Qdm tetramers. Our data further indicate correlation of Cd94 polymorphism with the two major subspecies of house mice in Europe. Together, these findings suggest that the Cd94LocA/NKG2A heterodimeric receptor is widely expressed among M. musculus subspecies musculus, with ligand-binding properties different from mice of subspecies domesticus, such as the C57BL/6 strain.

• Thiruchelvam-Kyle, Lavanya; Hoelsbrekken, Sigurd Erik; Sæther, Per Christian; Bjørnsen, Elisabeth Gyllensten; Pende, Daniela & Fossum, Sigbjørn [Show all 8 contributors for this article] (2017). The Activating Human NK Cell Receptor KIR2DS2 Recognizes a β2-Microglobulin–Independent Ligand on Cancer Cells. Journal of Immunology. ISSN 0022-1767. 198(7), p. 2556–2567. doi: 10.4049/jimmunol.1600930.

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