HIV Replication in Humanized IL-3/GM-CSF-Transgenic NOG Mice

Abstract

The development of mouse models that mimic the kinetics of Human Immunodeficiency Virus (HIV) infection is critical for the understanding of the pathogenesis of disease and for the design of novel therapeutic strategies. Here, we describe the dynamics of HIV infection in humanized NOD/Shi-scid-IL2rγ^null (NOG) mice bearing the human genes for interleukin (IL)-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF) (NOG-EXL mice). The kinetics of viral load, as well as the frequencies of T-cells, B-cells, Natural killer cells (NK), monocytes, and dendritic cells in blood and secondary lymphoid organs were evaluated throughout the time of infection. In comparison with a non-transgenic humanized mouse (NSG) strain, lymphoid and myeloid populations were more efficiently engrafted in humanized NOG-EXL mice, both in peripheral blood and lymphoid tissues. In addition, HIV actively replicated in humanized NOG-EXL mice, and infection induced a decrease in the percentage of CD4⁺ T-cells, inversion of the CD4:CD8 ratio, and changes in some cell populations, such as monocytes and dendritic cells, that recapitulated those found in human natural infection. Thus, the humanized IL-3/GM-CSF-transgenic NOG mouse model is suitable for the study of the dynamics of HIV infection and provides a tool for basic and preclinical studies.

Keywords: GM-CSF; HIV; Humanized mice (huNOG or huNOG-EXL); IL-3; NOG mice.

Figure 1

Cell subsets evaluated in huNOG-EXL mice. Representative gating strategy from blood cells for the identification of the cell populations evaluated. The number next to the gates represents the respective cell subset found in the adjacent table.

Figure 2

huNOG-EXL mice exhibit an efficient engraftment of lymphoid populations. Frequencies of CD45⁺ (A), CD3⁺ (B), and CD20⁺ (C) cells from total singlet cells, the CD4:CD8 ratio (D), and the frequencies of CD4⁺ (E) and CD8⁺ cells (F) that are CXCR5⁺ in blood (diamonds) and secondary lymphoid organs (SLO; spleen: circles; axillary lymph node: squares; mesenteric lymph node: triangles) from huNOG-EXL and huNSG mice. The p value of the Mann-Whitney test is shown. NS: Not statistically significant.

Figure 3

huNOG-EXL mice have higher levels of NK cells than huNSG mice. Frequencies of CD56^bright (A), CD56^dim (B), and CD56⁻ (C) NK cells (from FSC-A^lo CD3⁻ cells) in blood (diamonds) and secondary lymphoid organs (SLO; spleen: circles; axillary lymph node: squares; mesenteric lymph node: triangles) from huNOG-EXL and huNSG mice. The p value of the Mann-Whitney test is shown. NS: Not statistically significant.

Figure 4

huNOG-EXL mice exhibit an efficient engraftment of myeloid populations. Frequencies of CD14⁺ CD16⁻ (classical) monocytes from FSC-A^hi CD3⁻ cells (A), HLA-DR⁺ Lin 1⁻ cells from CD45⁺ cells (B), CD11c⁻ CD123⁺ plasmacytoid dendritic cells (C), and CD11c⁺ CD123⁻ myeloid dendritic cells (D), the latter from HLA-DR⁺ Lin 1⁻ cells, in blood (diamonds) and secondary lymphoid organs (SLO; spleen: circles; axillary lymph node: squares; mesenteric lymph node: triangles) from huNOG-EXL and huNSG mice. The p value of the Mann-Whitney test is shown. NS: Not statistically significant.

Figure 5

huNOG-EXL mice support the replication of HIV, with the consequent decrease in the level of engraftment and inversion of the CD4:CD8 ratio. Viral load (A,D), blood frequencies of CD45⁺ cells (B,E), and blood CD4:CD8 ratio (C,F) in huNOG-EXL (A–C) and huNSG (D–F) mice after infection with HIV (green diamonds: uninfected mice; red diamonds: HIV-infected mice). In A and D, the dashed lines indicate the limit of detection of the assay. In C and F, the dashed lines indicate the CD4:CD8 ratio = 1.

Figure 6

HIV infection in huNOG-EXL mice induces the decrease of circulating T-cells, B-cells, and CXCR5⁺ CD8⁺ T-cells. Frequencies of CD3⁺ cells (A) and CD20⁺ cells (B) from total singlet cells, CXCR5⁺ CD4⁺ T-cells (C), and CXCR5⁺ CD8⁺ T-cells (D) from total CD4⁺ and CD8⁺ T-cells, respectively, in huNOG-EXL mice after infection with HIV. In the left panels, the kinetics of blood populations are shown; in the middle panels, comparisons of blood populations between infected and uninfected mice in compiled data from 3, 5, and 7 weeks post-infection are shown; in the right panels, comparisons of secondary lymphoid organs (SLO; spleen: circles; axillary lymph node: squares; mesenteric lymph node: triangles)-confined populations between infected and uninfected mice are shown. In all the cases, green: uninfected mice; red: HIV-infected mice. The p value of the Mann-Whitney test is shown.

Figure 7

HIV infection in huNOG-EXL mice affects the frequencies of classical monocytes, dendritic cells, and CD56^bright NK cells. Frequencies of CD14⁺ CD16⁻ (classical) monocytes from FSC-A^hi CD3⁻ cells (A), HLA-DR⁺ Lin 1⁻ cells from CD45⁺ cells (B), CD11c⁻ CD123⁺ plasmacytoid dendritic cells from HLA-DR⁺ Lin 1⁻ cells (C), CD56^dim (D), and CD56^bright NK cells (E), the latter from FSC-A^lo CD3⁻ cells, in huNOG-EXL mice after infection with HIV. In the left panels, the kinetics of blood populations are shown; in the middle panels, comparisons of blood populations between infected and uninfected mice in compiled data from 3, 5, and 7 weeks post-infection are shown; in the right panels, comparisons of secondary lymphoid organs (SLO; spleen: circles; axillary lymph node: squares; mesenteric lymph node: triangles)-confined populations between infected and uninfected mice are shown. In all the cases, green: uninfected mice; red: HIV-infected mice. The p value of the Mann-Whitney test is shown.