Korean J Transplant.  2022 Nov;36(Supple 1):S129. 10.4285/ATW2022.F-2503.

Histopathologic evaluations on porcine vessel lacking GGTA1/CMAH/ β4galNT2/iGb3 genes in non-human primate xenotransplantation

• Chung YS
• Lee KW
• Choi M
• Shim J
• Choi K
• Kim SJ
• Park JB
• Kim TJ

• KMID: 2535645
• DOI: http://doi.org/10.4285/ATW2022.F-2503

Abstract

Background
Although alpha-galactosyltransferase knock out (GTKO) pigs overcome the hyper-acute-rejection in pig to non-human primate (NHP) xenotransplantation, it still remains severe acute humoral xenograft rejection. HD and Sda as non-Gal antigens should be eliminated for pig to human-primate xenotransplantation. A residual alpha-Gal epitope by isoglo-botrihexosylceramide synthase (iGb3s) on GTKO pig might be barrier. In current study, we evaluated the histopathology on pig-to-NHP immune cross-reactivity by comparing wild type (WT)-, GTKO-, GGTA1/CMAH/4GalNT2(TKO)- and GGTA1/ CMAH/4GalNT2/iGb3s (QKO)-porcine vessel (PV) xenograft from monkey (PVG).
Methods
WT-, GTKO-, TKO- and QKO-PVs were transplanted to cynomolgus monkey under immunosuppressive protocols. Pre-formed monkey IgM- and IgG-antibody binding to porcine PBMCs (pPBMCs) were determined by flow cytometry. Histopathology of PVG was evaluated through H&E staining and immunofluorescence images for CD3 T-cells, CD20 B-cells, IgM-, IgG-antibody binding, tissue factor (TF), C3 and CD42b by confocal microscopy.
Results
Preformed monkey plasma IgM-antibody bindings to WT pPBMCs were higher than those to the other three types of pPBMCs. However, preformed monkey plasma IgG-antibody bindings to all four types of pPBMCs have no differences. Endotheli-al cells (ECs) were completely destroyed, and thrombus was formed severely in WT-PVG on postoperative day (POD) 11. Although ECs were destroyed, thrombus was generated mildly in GTKO- and TKO-PVG on POD 15. In QKO-PVG on POD 16, ECs were barely destroyed and thrombus was generated minimally. CD3 T- and CD20 B-cells were abundant on the outer wall of GTKO- and TKOPVG on POD 90. IgM- and IgG-antibody binding to WT-, GTKO- and TKO-PVG were observed on POD 11–POD 15, but rarely to QKO-PVG on POD 16. TF on WT- and TKO-PVG were observed on POD 11–POD 15, but rarely on GTKO- and QKO-PVG POD 15– POD 16. C3 and CD42b on WT- and TKO-PVG were enriched on POD 11–POD 15, but rarely on GTKO- and QKO-PVG.
Conclusions
Our data suggest that coagulopathy could be modulated through inhibiting C3, CD42b and TF binding to QKO-PV in pig-to-NHP xenotransplantation model.