Search

Your search keyword '"Lee, Seung Hwan"' showing total 6,809 results
Start Over Author "Lee, Seung Hwan"
6,809 results on '"Lee, Seung Hwan"'

40. Expansion of cytotoxic natural killer cells in multiple myeloma patients using K562 cells expressing OX40 ligand and membrane-bound IL-18 and IL-21.

Author

Thangaraj, Jaya, Phan, Minh-Trang, Kweon, SoonHo, Kim, Jinho, Lee, Jong-Min, Hwang, Ilwoong, Park, Jeehun, Doh, Junsang, Lee, Seung-Hwan, Vo, Manh-Cuong, Chu, Tan-Huy, Song, Ga-Young, Ahn, Seo-Yeon, Jung, Sung-Hoon, Kim, Hyeoung-Joon, Cho, Duck, and Lee, Je-Jung

Subjects
IL-18, IL-21, Multiple Myeloma, NK cells, OX40L, Cells, Cultured, Coculture Techniques, Cytotoxicity, Immunologic, Gene Expression, Humans, Immunophenotyping, Interleukin-18, Interleukins, K562 Cells, Killer Cells, Natural, Lymphocyte Activation, Multiple Myeloma, OX40 Ligand, Transduction, Genetic, Transgenes
Abstract

BACKGROUND: Natural killer (NK) cell-based immunotherapy is a promising treatment approach for multiple myeloma (MM), but obtaining a sufficient number of activated NK cells remains challenging. Here, we report an improved method to generate ex vivo expanded NK (eNK) cells from MM patients based on genetic engineering of K562 cells to express OX40 ligand and membrane-bound (mb) IL-18 and IL-21. METHODS: K562-OX40L-mbIL-18/-21 cells were generated by transducing K562-OX40L cells with a lentiviral vector encoding mbIL-18 and mbIL-21, and these were used as feeder cells to expand NK cells from peripheral blood mononuclear cells of healthy donors (HDs) and MM patients in the presence of IL-2/IL-15. Purity, expansion rate, receptor expression, and functions of eNK cells were determined over four weeks of culture. RESULTS: NK cell expansion was enhanced by short exposure of soluble IL-18 and IL-21 with K562-OX40L cells. Co-culture of NK cells with K562-OX40L-mbIL-18/-21 cells resulted in remarkable expansion of NK cells from HDs (9,860-fold) and MM patients (4,929-fold) over the 28-day culture period. Moreover, eNK cells showed increased expression of major activation markers and enhanced cytotoxicity towards target K562, U266, and RPMI8226 cells. CONCLUSIONS: Our data suggest that genetically engineered K562 cells expressing OX40L, mbIL-18, and mbIL-21 improve the expansion of NK cells, increase activation signals, and enhance their cytolytic activity towards MM cells.

Published
2022

43. Fractional Chern insulators in magic-angle twisted bilayer graphene

Author

Xie, Yonglong, Pierce, Andrew T., Park, Jeong Min, Parker, Daniel E., Khalaf, Eslam, Ledwith, Patrick, Cao, Yuan, Lee, Seung Hwan, Chen, Shaowen, Forrester, Patrick R., Watanabe, Kenji, Taniguchi, Takashi, Vishwanath, Ashvin, Jarillo-Herrero, Pablo, and Yacoby, Amir

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics, Condensed Matter - Strongly Correlated Electrons
Abstract

Fractional Chern insulators (FCIs) are lattice analogues of fractional quantum Hall states that may provide a new avenue toward manipulating non-abelian excitations. Early theoretical studies have predicted their existence in systems with energetically flat Chern bands and highlighted the critical role of a particular quantum band geometry. Thus far, however, FCI states have only been observed in Bernal-stacked bilayer graphene aligned with hexagonal boron nitride (BLG/hBN), in which a very large magnetic field is responsible for the existence of the Chern bands, precluding the realization of FCIs at zero field and limiting its potential for applications. By contrast, magic angle twisted bilayer graphene (MATBG) supports flat Chern bands at zero magnetic field, and therefore offers a promising route toward stabilizing zero-field FCIs. Here we report the observation of eight FCI states at low magnetic field in MATBG enabled by high-resolution local compressibility measurements. The first of these states emerge at 5 T, and their appearance is accompanied by the simultaneous disappearance of nearby topologically-trivial charge density wave states. Unlike the BLG/hBN platform, we demonstrate that the principal role of the weak magnetic field here is merely to redistribute the Berry curvature of the native Chern bands and thereby realize a quantum band geometry favorable for the emergence of FCIs. Our findings strongly suggest that FCIs may be realized at zero magnetic field and pave the way for the exploration and manipulation of anyonic excitations in moir\'e systems with native flat Chern bands.

Published
2021
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results