Delayed rejection of porcine cartilage is averted by transgenic expression of α1,2‐fucosyltransferase

Abstract

The use of xenogeneic cells or tissues for tissue engineering applications may lead to advances in biomedical research. Hyperacute and delayed rejection are immunologic hurdles that must be addressed to achieve xenograft survival in the pig-to-primate setting. Expression of human alpha1,2-fucosyltransferase (HT) in the donor cell or tissue protects from hyperacute rejection (HAR) by reducing expression of Galalpha1,3-Gal epitope, the major xenoantigen recognized by human natural antibodies. We hypothesized that Galalpha1,3-Gal antigen contributes to delayed tissue rejection. To test this hypothesis, we transplanted control or HT-transgenic engineered porcine cartilage s.c. into alpha1,3-galactosyltransferase knockout (Gal KO) mice. Control porcine cartilage grafted in Gal KO mice was not susceptible to HAR but was rejected in several wk by a prominent cellular immune infiltrate and elevated antibody titers. In contrast, Gal KO mice receiving the HT engineered cartilage showed a markedly reduced anti-pig antibody response and no anti-Galalpha1,3-Gal-elicited antibody response. The HT implants had a mild cellular infiltrate that was confined to the graft periphery. Our study demonstrates that a marked reduction of Galalpha1,3-Gal antigen in HT-transgenic porcine cartilage confers resistance to a process of delayed rejection. Further development of tissue engineering applications that use genetically modified porcine tissues is encouraged.

TNF, Pig CD86, and VCAM-1 Identified as Potential Targets for Intervention in Xenotransplantation of Pig Chondrocytes

“…Moreover, the hIL-8 increased (as opposed to pIL-8) in correlation Cytokines and Induce U937 to Secrete hIL- 8 with the E/T ratio and in response to the pretreatment Subsequent experiments were conducted to determine with cytokines. Thus, these increases in hIL-8 secretion whether U937 and PCC develop a proinflammatory rewere more pronounced after coculture with cytokinesponse after coculture.…”

“…We further confirmed a key role of the Gal antigen in promoting rejection, as transgenic exJose, CA), washed, and resuspended in Ham's F12 (Invitrogen)/20% FBS (Biological Industries, Kibbutz Beit pression of H transferase (HT) in porcine cartilage markedly reduced Gal antigen expression and averted Haemek, Israel) supplemented with penicillin, streptomycin, and gentamicin (200 U/ml, 200 and 50 µg/ml, the anti-Gal antibody response induced after transplantation into α1,3-galactosyltransferase-deficient mice (Gal respectively, Invitrogen). Cells were seeded into tissue culture flasks and maintained as monolayer in Ham's KO mice, which lack the Gal epitope) (8). Moreover, HT-transgenic grafts led to a milder anti-pig antibody F12/DMEM (1:1) or DMEM (Invitrogen) supplemented with 10% FBS and 25 mg/L endothelial mitogen (EM, response and showed a diminished cellular immune infiltrate (8).…”

“…Cells were seeded into tissue culture flasks and maintained as monolayer in Ham's KO mice, which lack the Gal epitope) (8). Moreover, HT-transgenic grafts led to a milder anti-pig antibody F12/DMEM (1:1) or DMEM (Invitrogen) supplemented with 10% FBS and 25 mg/L endothelial mitogen (EM, response and showed a diminished cellular immune infiltrate (8).…”

Multiple Receptors Trigger Human NK Cell-Mediated Cytotoxicity against Porcine Chondrocytes

“…In particular, the use of genetically engineered porcine chondrocytes is being considered for the repair of cartilage defects (1,2). With this goal, we and others are studying the rejection process of xenogeneic pig chondrocytes/cartilage to identify key molecules that can be modified to prolong engraftment (1)(2)(3)(4). The rejection of pig cartilage implants in nonhuman primates develops during weeks to months and is slow compared with that of vascularized organs (3).…”

“…The rejection of pig cartilage implants in nonhuman primates develops during weeks to months and is slow compared with that of vascularized organs (3). Nevertheless, xenogeneic cartilage is rejected by humoral and cellular mechanisms that target, among other molecules, the galactose a1,3-galactose (aGal) Ag (1,3). Transplantation of pig cartilage induces a strong Ab response that comprises anti-aGal and anti-non-aGal Abs (1,3,5).…”