NKG-H2-Ab1 KO Mice

Catalog Number: C001498

Strain Name: NOD.Cg-Prkdc^scid Il2rg^em1cyaH2-Ab1^em1cya/Cya

Genetic Background: NKG

Reproduction: Homozygote x Homozygote

Strain Description

NKG mice are a type of severe immunodeficient mouse developed by Cyagen by knocking out the Il2rg gene in the NOD-Scid background strain. This strain lacks mature T, B, and NK immune cells, has reduced complement activity, and weak phagocytic activity of macrophages against human cells. Therefore, NKG mice can efficiently engraft human hematopoietic stem cells (HSC), peripheral blood mononuclear cells (PBMC), patient-derived xenografts (PDX), or adult stem cells and tissues.

In the field of immunology, there are differences between humans and mice in terms of physiology and the immune system. Therefore, research conducted directly on mice does not fully reflect the situation in humans. By transplanting human peripheral blood mononuclear cells (PBMCs) or human hematopoietic stem cells (HSCs) into immunodeficient mice, the mouse’s immune system can be partially or completely replaced by the human immune system, which can simulate the function of the human immune system in vivo and provide an effective model for studying the human immune system. Transplanting PBMCs into NKG mice has the advantages of high immune reconstitution efficiency and fast speed. After 3 weeks of transplantation, the average proportion of human CD45+ cells in peripheral blood exceeds 40%. Due to individual differences in donor cells, the reconstitution efficiency of some PBMC donors in NKG mice may be higher. However, due to the mismatch between human immune cells and mouse major histocompatibility complex (MHC) molecules, graft-versus-host disease (GvHD) occurs, and transplanted human immune cells (including T cells, B cells, NK cells, etc.) attack mouse tissues, causing inflammation and tissue damage, ultimately leading to rapid death of mice. This results in a very limited experimental window period.

In mice, MHC is commonly referred to as the H-2 complex. The H2-Ab1 (Histocompatibility 2, class II antigen A, beta 1) gene encodes a part of the mouse MHC class II molecules. This complex is primarily present on the surface of antigen-presenting cells such as macrophages, dendritic cells, and B cells. It plays a crucial role in presenting fragments of foreign substances, such as bacteria or viruses, to helper T cells (CD4+ T cells). This antigen presentation is a fundamental step in initiating adaptive immune responses. Studies have shown that transplanting PBMCs into MHC II-deficient mice can prevent lethal graft-versus-host disease (GvHD) caused by CD4+ T cells[1-2]. The absence of H2-Ab1 can affect the recognition of mouse MHC molecules by human T cells, thereby mitigating GvHD and extending the experimental window for PBMC immune reconstitution. NKG-H2-Ab1 KO mice are generated by knocking out the H2-Ab1 gene on the background of NKG mice. Compared to NKG mice, NKG-H2-Ab1 KO mice can effectively reconstitute CD8+ T cells and exhibit improved survival after PBMC transplantation. They can be used for long-term studies on PBMC immune system reconstitution.

Validation

1. Growth status of NKG-H2-Ab1 KO mice after PBMC transplantation

Figure 1. Survival curve and GvHD scores after PBMC transplantation in NKG mice and NKG-H2-Ab1 KO mice. After intravenous injection (i.v.) of human PBMC cells (5 x 106) into 6-week-old female NKG mice and NKG-H2-Ab1 KO mice, the survival period and GvHD scores of the mice were recorded. The results showed that compared with NKG mice, NKG-H2-Ab1 KO mice exhibited higher survival rates and longer survival periods after PBMC transplantation. Moreover, the GvHD scores of NKG-H2-Ab1 KO mice were lower, indicating a delayed onset of GvHD.

 

2. Reconstitution of human-derived CD45 and T cells after PBMC transplantation

Figure 2. Proportions of human CD45+ lymphocytes and human CD3 cells in the peripheral blood after PBMC transplantation in NKG mice and NKG-H2-Ab1 KO mice. After intravenous injection (i.v.) of human PBMC cells (5 x 106) into 6-week-old female NKG mice and NKG-H2-Ab1 KO mice, the proportions of human cells in the peripheral blood were measured. The results showed that the immune reconstitution trend of NKG-H2-Ab1 KO mice was consistent with that of NKG mice. After 3 weeks of transplantation, the average proportion of human CD45+ cells in the peripheral blood exceeded 40%* and both groups were mainly composed of T cells, indicating that NKG-H2-Ab1 KO mice can successfully reconstitute the human immune system after PBMC transplantation.

*Due to individual differences in donor cells, the reconstitution efficiency of some PBMC donors in this mouse may be higher.

 

3. Reconstitution of human CD4+ T cells and CD8+ T cells after PBMC transplantation

Figure 3. Distribution of human T cell subsets in NKG mice and NKG-H2-Ab1 KO mice after PBMC transplantation. The immune system reconstitution in both NKG mice and NKG-H2-Ab1 KO mice after PBMC transplantation is mainly composed of T cells. After 4 weeks of transplantation, the proportion of CD8+ T cells in NKG-H2-Ab1 KO mice is significantly higher than that in NKG mice, indicating that NKG-H2-Ab1 KO mice can effectively reconstitute CD8 cells.

 

References

[1] Koyama M, Mukhopadhyay P, Schuster IS, Henden AS, Hülsdünker J, Varelias A, Vetizou M, Kuns RD, Robb RJ, Zhang P, Blazar BR, Thomas R, Begun J, Waddell N, Trinchieri G, Zeiser R, Clouston AD, Degli-Esposti MA, Hill GR. MHC Class II Antigen Presentation by the Intestinal Epithelium Initiates Graft-versus-Host Disease and Is Influenced by the Microbiota. Immunity. 2019 Nov 19;51(5):885-898.e7.

[2] L Covassin, J Laning, R Abdi, D L Langevin, N E Phillips, L D Shultz, M A Brehm, Human peripheral blood CD4 T cell-engrafted non-obese diabetic-scid IL2rγnull H2-Ab1 tm1Gru Tg (human leucocyte antigen D-related 4) mice: a mouse model of human allogeneic graft-versus-host disease, Clinical and Experimental Immunology, Volume 166, Issue 2, November 2011, Pages 269–280.