Delayed xenograft rejection is not mitigated by depletion of macrophages and NK cells

Human natural killer (NK) cell-mediated response plays an important role in xenograft rejection. In the case of pig-to-human xenotransplantation, it has been suggested that NK cells are involved in delayed-type rejection, which is characterized by pig endothelial cell (pEC) activation, direct lysis, and secretion of proinflammatory cytokines. NK cell activation can be a direct barrier to the potential use of pig organs for human xenograft transplantation. Therefore, it is important to suppress the NK cell activity on pig-to-human xenografts. Expression of HLA-G1 (non-classical major histocompatibility complex class I molecules) inhibits the cytotoxic activity of NK cells and has been proposed as a potential solution to overcome NK cell-mediated xenogeneic cytotoxicity in pEC. In this study, we transfected the HLA-G1 gene into mini-pig fetal fibroblasts to produce 2 HLA-G1 clonal cell lines. These cell lines were used to produce cloned HLA-G1 transgenic mini-pigs by nuclear transfer (NT). The presence of the HLA-G1 gene in transgenic mini-pigs was confirmed by PCR. The expression of HLA-G1 was detected by flow cytometry-immunohistochemistry assay. Mini-pig fibroblasts derived from a 35-day-old cloned fetus also showed characteristics similar to those of HLA-G1 clonal cell lines. The expressed HLA-G1 significantly suppressed NK-mediated cell lysis, and the rate of NK 92MI cell cytotoxicity was reduced as compared to the control group (HLA-G1: 46.7 � 4.5%; control: 4.6 � 13.3%; P < 0.05). In conclusion, transgenic cloned mini-pigs expressing HLA-G1 were produced by NT for the first time. It is expected that these mini-pigs could be used to overcome the NK cell-mediated rejection in xenotransplantation.

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Negligible role for NK cells and macrophages in delayed xenograft rejection

Transplant International ◽

10.1111/j.1432-2277.2000.tb02092.x ◽

2000 ◽

Vol 13 (S1) ◽

pp. S504-S507 ◽

Cited By ~ 4

Author(s):

K.A. Overdam ◽

C.A.E. Verbakel ◽

E. A. Kouwenhoven ◽

N. Rooijen ◽

R.W.F. Bruin ◽

...

Keyword(s):

Nk Cells ◽

Xenograft Rejection

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Delayed xenograft rejection is not mitigated by depletion of macrophages and NK cells

Immunology Letters ◽

10.1016/s0165-2478(97)89009-8 ◽

1997 ◽

Vol 56 ◽

pp. 490

Author(s):

R.L. Marquet ◽

K.A. van Overdam ◽

N. van Rooijen ◽

R.W.F. de Bruin ◽

J.N.M. Ijzermans

Keyword(s):

Nk Cells ◽

Xenograft Rejection

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Genetic Control Of Natural Killing and In Vivo Tumor Elimination by the Chok Locus

Journal of Experimental Medicine ◽

10.1084/jem.188.12.2243 ◽

1998 ◽

Vol 188 (12) ◽

pp. 2243-2256 ◽

Cited By ~ 35

Author(s):

Azza H. Idris ◽

Koho Iizuka ◽

Hamish R.C. Smith ◽

Anthony A. Scalzo ◽

Wayne M. Yokoyama

Keyword(s):

Nk Cells ◽

Cho Cells ◽

Molecular Mechanisms ◽

Nk Cell ◽

Interleukin 2 ◽

Chinese Hamster ◽

Mouse Strains ◽

Xenograft Rejection ◽

Natural Killing

The molecular mechanisms underlying target recognition during natural killing are not well understood. One approach to dissect the complexities of natural killer (NK) cell recognition is through exploitation of genetic differences among inbred mouse strains. In this study, we determined that interleukin 2–activated BALB/c-derived NK cells could not lyse Chinese hamster ovary (CHO) cells as efficiently as C57BL/6-derived NK cells, despite equivalent capacity to kill other targets. This strain-determined difference was also exhibited by freshly isolated NK cells, and was determined to be independent of host major histocompatibility haplotype. Furthermore, CHO killing did not correlate with expression of NK1.1 or 2B4 activation molecules. Genetic mapping studies revealed linkage between the locus influencing CHO killing, termed Chok, and loci encoded within the NK gene complex (NKC), suggesting that Chok encodes an NK cell receptor specific for CHO cells. In vivo assays recapitulated the in vitro data, and both studies determined that Chok regulates an NK perforin–dependent cytotoxic process. These results may have implications for the role of NK cells in xenograft rejection. Our genetic analysis suggests Chok is a single locus that affects NK cell–mediated cytotoxicity similar to other NKC loci that also regulate the complex activity of NK cells.

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The Role of NK Cells in Pig-to-Human Xenotransplantation

Journal of Immunology Research ◽

10.1155/2017/4627384 ◽

2017 ◽

Vol 2017 ◽

pp. 1-19 ◽

Cited By ~ 13

Author(s):

Gisella Puga Yung ◽

Mårten K. J. Schneider ◽

Jörg D. Seebach

Keyword(s):

Nk Cells ◽

Molecular Mechanisms ◽

Nk Cell ◽

Ex Vivo ◽

Functional Characterization ◽

Therapeutic Interventions ◽

Future Research ◽

Transgenic Pigs ◽

Xenograft Rejection ◽

Cell Responses

Recruitment of human NK cells to porcine tissues has been demonstrated in pig organs perfused ex vivo with human blood in the early 1990s. Subsequently, the molecular mechanisms leading to adhesion and cytotoxicity in human NK cell-porcine endothelial cell (pEC) interactions have been elucidated in vitro to identify targets for therapeutic interventions. Specific molecular strategies to overcome human anti-pig NK cell responses include (1) blocking of the molecular events leading to recruitment (chemotaxis, adhesion, and transmigration), (2) expression of human MHC class I molecules on pECs that inhibit NK cells, and (3) elimination or blocking of pig ligands for activating human NK receptors. The potential of cell-based strategies including tolerogenic dendritic cells (DC) and regulatory T cells (Treg) and the latest progress using transgenic pigs genetically modified to reduce xenogeneic NK cell responses are discussed. Finally, we present the status of phenotypic and functional characterization of nonhuman primate (NHP) NK cells, essential for studying their role in xenograft rejection using preclinical pig-to-NHP models, and summarize key advances and important perspectives for future research.

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