In Vivo Lentiviral Gene Delivery of HLA-DR and Vaccination of Humanized Mice for Improving the Human T and B Cell Immune Reconstitution

Abstract

Humanized mouse models generated with human hematopoietic stem cells (HSCs) and reconstituting the human immune system (HIS-mice) are invigorating preclinical testing of vaccines and immunotherapies. We have recently shown that human engineered dendritic cells boosted bonafide human T and B cell maturation and antigen-specific responses in HIS-mice. Here, we evaluated a cell-free system based on in vivo co-delivery of lentiviral vectors (LVs) for expression of a human leukocyte antigen (HLA-DRA*01/ HLA-DRB1*0401 functional complex, “DR4”), and a LV vaccine expressing human cytokines (GM-CSF and IFN-α) and a human cytomegalovirus gB antigen (HCMV-gB). Humanized NOD/Rag1null/IL2Rγnull (NRG) mice injected by i.v. with LV-DR4/fLuc showed long-lasting (up to 20 weeks) vector distribution and expression in the spleen and liver. In vivo administration of the LV vaccine after LV-DR4/fLuc delivery boosted the cellularity of lymph nodes, promoted maturation of terminal effector CD4+ T cells, and promoted significantly higher development of IgG+ and IgA+ B cells. This modular lentigenic system opens several perspectives for basic human immunology research and preclinical utilization of LVs to deliver HLAs into HIS-mice.

T-cell development and activation in humanized mice lacking mouse major histocompatibility complexes

“…Recently, we showed an alternative lentivirus-based approach to deliver the expression of HLA-DR4. LV were used systemically to introduce HLA-DR4 and hGM-CSF/hIFN-α/HCMV-gB in huNRG mice, enhancing B-cell development compared to animals that did not receive the LV injection (Kumar et al , 2021). Therefore, a plausible explanation is that the NRG background seems to be fitter to promote B cell development than the NSG strain.…”

“…Other groups demonstrated that humanization of transgenic NSG- and NRG-derived strains expressing human class I and class II MHCs/HLAs, as expected, showed improvements in T-cell development and cytotoxic functions (Najima et al , 2016; Danner et al , 2011; Majji et al , 2016; Masse-Ranson et al , 2019; Suzuki et al , 2012). Due to the difficulties of generating transgenic mice with several different HLA alleles, we explored lentiviral vector (LV) in vivo delivery of HLA-DRB1*04:01 (DR4) into huNRG mice (Kumar et al , 2021). Upon co-administration with LV expressing human GM-CSF/IFN-α and gB, we observed activation of T-cell and B-cell development (Kumar et al , 2021).…”

“…Due to the difficulties of generating transgenic mice with several different HLA alleles, we explored lentiviral vector (LV) in vivo delivery of HLA-DRB1*04:01 (DR4) into huNRG mice (Kumar et al , 2021). Upon co-administration with LV expressing human GM-CSF/IFN-α and gB, we observed activation of T-cell and B-cell development (Kumar et al , 2021).…”

Recent Developments in NSG and NRG Humanized Mouse Models for Their Use in Viral and Immune Research

“…Since this mouse strain is more resistant to irradiation than NSG strains, mice can be irradiated with higher doses (i.e., 450 cGy). Frequencies of human immune cell subsets in peripheral blood are determined around 15 to 17 weeks after cell transplantation using flow cytometry and antibody panels similar to the protocols used in NSG mice [ 48 , 49 , 50 , 51 , 52 ].…”

“…Several studies have used HIS NRG mice to model HCMV infection and immune response [ 48 , 51 , 52 , 82 ]. In this model, HCMV reactivation by treatment with recombinant human G-CSF promoted the detection of the virus in the spleen, lymph nodes, liver, salivary glands and bone marrow.…”