Post-transplant upregulation of chemokine messenger RNA in non-human primate recipients of intraportal pig islet xenografts

Xenotransplantation. 2005 Jul;12(4):293-302. doi: 10.1111/j.1399-3089.2005.00228.x.


Background: We have previously shown that pig-to-primate intraportal islet xenografts reverse diabetes, escape hyperacute rejection, and undergo acute cellular rejection in non-immunosuppressed recipients. To gain a better understanding of mechanisms contributing to xenoislet rejection in non-human primates we examined gene expression in livers bearing islet xenografts in the first 72 h after transplantation.

Methods: Liver specimens were collected at sacrifice from seven non-immunosuppressed rhesus macaques at 12, 24, 48 and 72 h after intraportal porcine islet transplantation. Following total RNA extraction, mRNA was quantified using SYBR green real-time reverse transcription polymerase chain reaction (RT-PCR) for species-specific immune response genes. Data were analyzed using comparative cycle threshold (Ct) analysis, adjusted for specific primer-efficiencies and normalized to cyclophilin expression.

Results: Porcine insulin mRNA was detected in all liver samples. Cluster analysis revealed differential gene expression patterns at 12 and 24 h (early) compared with at 48 and 72 h (late) post-transplant. Gene expression patterns were associated with histological findings of predominantly neutrophils and only a few lymphocytes at 12 and 24 h and an increasing number of lymphocytes and macrophages at 48 and 72 h. Transcript levels of CXCR3 and its ligands, interferon-inducible protein 10 (IP-10) and monokine induced by IFN-gamma (Mig), significantly increased between early and late time points together with expression of MIP-1alpha, regulated on activation normal T expressed and secreted protein (RANTES) and MCP-1. CCR5 showed only a marginal, non-significant increase. Fas ligand, perforin and granzyme B transcripts were all elevated at 48 and 72 h post-transplant.

Conclusions: Our data suggest that CXCR3, with ligands IP-10 and Mig, is involved in T cell recruitment in acute islet xenograft rejection in non-human primates. Upregulation of RANTES and MIP-1alpha transcripts in the absence of a significant CCR5 increase suggests a possible involvement of other chemokine receptors. MCP-1 expression is associated with T cell and macrophage infiltration. Elevated cytotoxic effector molecule expression (Fas ligand, perforin, granzyme B) indicates T-cell mediated graft destruction by cytotoxic and cytolytic mechanisms within 48 to 72 h after transplantation. These results identify the CXCR3-mediated chemoattractant pathway as an immunosuppressive target in pig-to-primate islet xenotransplantation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • CD4 Antigens / genetics
  • CD8 Antigens / genetics
  • Chemokines / genetics*
  • Chemokines / immunology
  • Cytokines / genetics
  • Female
  • Gene Expression Profiling
  • Inflammation / genetics
  • Islets of Langerhans Transplantation* / immunology
  • Macaca / genetics*
  • Macaca / immunology*
  • Macaca / surgery
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Receptors, CCR5 / metabolism
  • Receptors, CXCR3
  • Receptors, Chemokine / metabolism
  • Species Specificity
  • Swine* / immunology
  • Swine* / surgery
  • Time Factors
  • Transcription, Genetic / genetics
  • Transplantation, Heterologous* / immunology
  • Up-Regulation / genetics*


  • CD4 Antigens
  • CD8 Antigens
  • CXCR3 protein, human
  • Chemokines
  • Cytokines
  • RNA, Messenger
  • Receptors, CCR5
  • Receptors, CXCR3
  • Receptors, Chemokine