Novel humanized-PBMC mouse model with delayed onset of GVHD for preclinical HIV research.

Humanized mouse models are based on the engraftment of human cells in immunodeficient mouse strains, most notably the NSG strain. Most used models have a major limitation in common, the development of graft-versus-host disease (GVHD). GVHD not only introduces variabilities into the research data but also leads to animal welfare concerns. A new mouse strain, B6.129S-Rag2tm1Fwa CD47tm1Fpl Il2rgtm1Wjl/J which lacks Rag1, IL2rg, and CD47 (triple knockout or TKO), is resistant to GVHD development. We transplanted TKO mice with human peripheral blood mononuclear cells (PBMCs) to establish a new humanized PBMC (hu-PBMC) mouse model. A cohort of these mice was infected with HIV-1 and monitored for plasma HIV viremia and CD4+ T cell depletion. The onset and progression of GVHD were monitored by clinical signs. This study demonstrates that TKO mice transplanted with human PBMCs support engraftment of human immune cells in primary and secondary lymphoid tissues, rectum, and brain. Moreover, the TKO hu-PBMC model supports HIV-1 infection via intraperitoneal, rectal, or vaginal routes, as confirmed by robust plasma HIV viremia and CD4+ T cell depletion. Lastly, TKO mice showed a delayed onset of GVHD clinical signs (∼28 days) and exhibited significant decreases in plasma levels of TNFβ. Based on these results, the TKO hu-PBMC mouse model not only supports humanization and HIV-1 infection but also has a delayed onset of GVHD development, making this model a valuable tool in HIV research. Importance Currently, there is no cure or vaccine for HIV infection, thus continued research is needed to end the HIV pandemic. While many animal models are used in HIV research, none is used more than the humanized mouse model. A major limitation with current humanized mouse models is the development of graft-versus-host disease (GVHD). Here, we show a novel humanized-PBMC mouse model that has a delayed onset GVHD development and supports and models HIV infection comparable to well-established humanized mouse models.