In Vivo Analysis of Human Immune Responses in Immunodeficient Rats

Transplantation. 2020 Apr;104(4):715-723. doi: 10.1097/TP.0000000000003047.


Background: Humanized immune system immunodeficient mice have been extremely useful for the in vivo analyses of immune responses in a variety of models, including organ transplantation and graft versus host disease (GVHD) but they have limitations. Rat models are interesting complementary alternatives presenting advantages over mice, such as their size and their active complement compartment. Immunodeficient rats have been generated but human immune responses have not yet been described.

Methods: We generated immunodeficient Rat Rag-/- Gamma chain-/- human signal regulatory protein alpha-positive (RRGS) rats combining Rag1 and Il2rg deficiency with the expression of human signal regulatory protein alpha, a negative regulator of macrophage phagocytosis allowing repression of rat macrophages by human CD47-positive cells. We then immune humanized RRGS animals with human peripheral blood mononuclear cells (hPBMCs) to set up a human acute GVHD model. Treatment of GVHD was done with a new porcine antihuman lymphocyte serum active through complement-dependent cytotoxicity. We also established a tumor xenograft rejection model in these hPBMCs immune system RRGS animals by subcutaneous implantation of a human tumor cell line.

Results: RRGS animals receiving hPBMCs showed robust and reproducible reconstitution, mainly by T and B cells. A dose-dependent acute GVHD process was observed with progressive weight loss, tissue damage, and death censoring. Antihuman lymphocyte serum (L1S1) antibody completely prevented acute GVHD. In the human tumor xenograft model, detectable tumors were rejected upon hPBMCs injection.

Conclusions: hPBMC can be implanted in RRGS animals and elicit acute GVHD or rejection of human tumor cells and these are useful models to test new immunotherapies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antigens, Differentiation / genetics
  • Antigens, Differentiation / immunology*
  • Antilymphocyte Serum / pharmacology
  • Breast Neoplasms / immunology
  • Breast Neoplasms / pathology
  • Breast Neoplasms / therapy
  • Cell Line, Tumor
  • Disease Models, Animal
  • Female
  • Graft vs Host Disease / drug therapy
  • Graft vs Host Disease / genetics
  • Graft vs Host Disease / immunology
  • Heterografts
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / immunology*
  • Humans
  • Immunocompromised Host*
  • Immunoglobulin gamma-Chains / genetics
  • Immunoglobulin gamma-Chains / immunology*
  • Immunologic Deficiency Syndromes / genetics
  • Immunologic Deficiency Syndromes / immunology*
  • Leukocytes, Mononuclear / immunology
  • Leukocytes, Mononuclear / transplantation*
  • Rats, Sprague-Dawley
  • Rats, Transgenic
  • Receptors, Immunologic / genetics
  • Receptors, Immunologic / immunology*
  • Xenograft Model Antitumor Assays


  • Antigens, Differentiation
  • Antilymphocyte Serum
  • Homeodomain Proteins
  • Immunoglobulin gamma-Chains
  • Receptors, Immunologic
  • SIRPA protein, human
  • RAG-1 protein