An Improved Protocol for Efficient Engraftment in NOD/LTSZ-SCIDIL-2RγNULL Mice Allows HIV Replication and Development of Anti-HIV Immune Responses

Maneesh Singh,Ellen Van Gulck,Guido Vanham,Caroline Thielen,Michel Moutschen,Souad Rahmouni,Dolores Vaira,Pratibha Singh,Gilles Gaudray,Claire Vandergeeten,Lucia Musumeci,Laurence De Leval,Laurence Delacroix

doi:10.1371/journal.pone.0038491

Maneesh Singh, Ellen Van Gulck + Show 11 more

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https://doi.org/10.1371/journal.pone.0038491

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Abstract

Cord blood hematopoietic progenitor cells (CB-HPCs) transplanted immunodeficient NOD/LtsZ-scidIL2Rγnull (NSG) and NOD/SCID/IL2Rγnull (NOG) mice need efficient human cell engraftment for long-term HIV-1 replication studies. Total body irradiation (TBI) is a classical myeloablation regimen used to improve engraftment levels of human cells in these humanized mice. Some recent reports suggest the use of busulfan as a myeloablation regimen to transplant HPCs in neonatal and adult NSG mice. In the present study, we further ameliorated the busulfan myeloablation regimen with fresh CB-CD34+cell transplantation in 3–4 week old NSG mice. In this CB-CD34+transplanted NSG mice engraftment efficiency of human CD45+cell is over 90% in peripheral blood. Optimal engraftment promoted early and increased CD3+T cell levels, with better lymphoid tissue development and prolonged human cell chimerism over 300 days. These humanized NSG mice have shown long-lasting viremia after HIV-1JRCSF and HIV-1Bal inoculation through intravenous and rectal routes. We also saw a gradual decline of the CD4+T cell count, widespread immune activation, up-regulation of inflammation marker and microbial translocation after HIV-1 infection. Humanized NSG mice reconstituted according to our new protocol produced, moderate cellular and humoral immune responses to HIV-1 postinfection. We believe that NSG mice reconstituted according to our easy to use protocol will provide a better in vivo model for HIV-1 replication and anti-HIV-1 therapy trials.

Highlights

In recent years, efforts have been made to reconstitute a functional human immune system in murine models [1,2]
Busulfan improves human CD45+ cell engraftment levels in humanized NSG mice, some limitation persists in the published protocols [12,14,15]
With the goal to improve busulfan-based humanization protocols, we first treated a group of twenty 8–9 week old mice with i.p. injection of busulfan 20 mg/kg, 24 hours prior to i.v.transplantation with 16105 frozen CBCD34+ cells

Summary

Introduction

Efforts have been made to reconstitute a functional human immune system in murine models [1,2]. Satisfactory levels of human cell engraftment have usually been achieved after TBI conditioning and CD34+ cell transplantation in newborn or 8–9 week old mice [2,3,4,5,6,7]. These humanized NSG and NOG mouse models have allowed sufficient levels of human cell chimerism and are suitable for HIV-1 infection studies [5,7,11]

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