June 2022
Volume 63, Issue 7
Open Access
ARVO Annual Meeting Abstract  |   June 2022
Pre-existing porcine anti-human antibodies: Implications for xenotransplantation studies
Author Affiliations & Notes
  • Hannah Cobb
    CellSight Ocular Stem Cell and Regeneration Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, Colorado, United States
  • Silvia Aparicio-Domingo
    CellSight Ocular Stem Cell and Regeneration Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, Colorado, United States
  • Kang Li
    CellSight Ocular Stem Cell and Regeneration Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, Colorado, United States
  • Miguel Flores-Bellver
    CellSight Ocular Stem Cell and Regeneration Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, Colorado, United States
  • Marc Mathias
    CellSight Ocular Stem Cell and Regeneration Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, Colorado, United States
    Ophthalmology, University of Colorado Health, Aurora, Colorado, United States
  • Alan Palestine
    Ophthalmology, University of Colorado Health, Aurora, Colorado, United States
  • Valeria Canto Soler
    CellSight Ocular Stem Cell and Regeneration Program, Department of Ophthalmology, Sue Anschutz-Rodgers Eye Center, University of Colorado, School of Medicine, Aurora, Colorado, United States
    University of Colorado Gates Center for Regenerative Medicine, Aurora, Colorado, United States
  • Footnotes
    Commercial Relationships   Hannah Cobb None; Silvia Aparicio-Domingo None; Kang Li None; Miguel Flores-Bellver None; Marc Mathias None; Alan Palestine None; Valeria Canto Soler None
  • Footnotes
    Support  Department of Defense W81XWH-20-1-0748, The Gates Grubstake Award GGF012-18-01, The Solich Fund, Sue Anschutz-Rodgers Fund, CellSight Fund, Unrestricted Research Award from Research to Prevent Blindness
Investigative Ophthalmology & Visual Science June 2022, Vol.63, 2438 – F0382. doi:
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    • Get Citation

      Hannah Cobb, Silvia Aparicio-Domingo, Kang Li, Miguel Flores-Bellver, Marc Mathias, Alan Palestine, Valeria Canto Soler; Pre-existing porcine anti-human antibodies: Implications for xenotransplantation studies. Invest. Ophthalmol. Vis. Sci. 2022;63(7):2438 – F0382.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Xenotransplantation in animal models is a necessary step to reach clinical trials in humans. However, transplantation of human cells into animal models results in severe immune rejection responses. To determine the mechanisms underlying xenotransplant rejection in porcine models, we tested the hypothesis of the potential presence of pre-existing anti-human antibodies that could be responsible for immediate recognition and rejection of transplanted human cells.

Methods : Transplants containing neural retina and retinal pigmented epithelium (RPE) cells derived from human induced pluripotent stem cells (hiPSCs) were implanted in the subretinal space of P23H transgenic and Yucatan pigs. Blood was collected before transplantation (basal level) and weekly for 6 weeks post transplantation. Serum derived from blood was used as a probe in dot blot and western blot assays to attempt to quantify and identify the presence of porcine antibodies against human neural retinal cells, RPE cells, and undifferentiated hiPSC in the weeks prior to and post-surgery. Protein bands identified in western blots are currently being analyzed by mass spectrometry.

Results : Serum collected throughout the 6 weeks post transplantation resulted in positive dot blot signals of relatively equal intensity, inconsistent with a gradually increasing immune rejection process. Furthermore, positive signals were identified from naive serum, collected prior to transplantation, suggesting that the animals expressed pre-existing anti-human antibodies. Further analysis revealed a discrete number of distinct bands in samples corresponding to human neural retina, RPE, and hiPSC, suggesting that pigs expressed antibodies against specific human proteins. Naïve serum from both P23H transgenic and Yucatan pigs recognized equivalent molecular weight bands in neural retina (90kD, 70kD, and 45kD), RPE (70kD, and 45kD), and undifferentiated hiPSC (90kD, and 70kD) samples.

Conclusions : These studies suggest that xenotransplantation of hiPSC-derived retinal transplants in pigs is challenged by the presence of pre-existing anti-human antibodies in the naïve animal model. Follow-up studies will aim at identifying the specific human proteins against which pigs possess pre-existing immunity. Identification of these proteins would be instrumental in devising appropriate strategies to prevent xenotransplant rejection in pre-clinical porcine models.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.

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