In Vivo Suppression of HIV by Antigen Specific T Cells Derived from Engineered Hematopoietic Stem Cells

Division of Hematology-Oncology, The David Geffen School of Medicine at UCLA, Los Angeles, California, United States of America.
PLoS Pathogens (Impact Factor: 7.56). 04/2012; 8(4):e1002649. DOI: 10.1371/journal.ppat.1002649
Source: PubMed


The HIV-specific cytotoxic T lymphocyte (CTL) response is a critical component in controlling viral replication in vivo, but ultimately fails in its ability to eradicate the virus. Our intent in these studies is to develop ways to enhance and restore the HIV-specific CTL response to allow long-term viral suppression or viral clearance. In our approach, we sought to genetically manipulate human hematopoietic stem cells (HSCs) such that they differentiate into mature CTL that will kill HIV infected cells. To perform this, we molecularly cloned an HIV-specific T cell receptor (TCR) from CD8+ T cells that specifically targets an epitope of the HIV-1 Gag protein. This TCR was then used to genetically transduce HSCs. These HSCs were then introduced into a humanized mouse containing human fetal liver, fetal thymus, and hematopoietic progenitor cells, and were allowed to differentiate into mature human CD8+ CTL. We found human, HIV-specific CTL in multiple tissues in the mouse. Thus, genetic modification of human HSCs with a cloned TCR allows proper differentiation of the cells to occur in vivo, and these cells migrate to multiple anatomic sites, mimicking what is seen in humans. To determine if the presence of the transgenic, HIV-specific TCR has an effect on suppressing HIV replication, we infected with HIV-1 mice expressing the transgenic HIV-specific TCR and, separately, mice expressing a non-specific control TCR. We observed significant suppression of HIV replication in multiple organs in the mice expressing the HIV-specific TCR as compared to control, indicating that the presence of genetically modified HIV-specific CTL can form a functional antiviral response in vivo. These results strongly suggest that stem cell based gene therapy may be a feasible approach in the treatment of chronic viral infections and provide a foundation towards the development of this type of strategy.

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Available from: Christian Aguilera, Aug 26, 2015
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    • "Additional gene therapy approaches that involve modulating anti-viral immune responses have also been evaluated in humanized mice. These include the generation of HIV-specific cytotoxic T lymphocytes via transgenic expression of a T cell receptor delivered to hematopoietic progenitor cells (Kitchen et al., 2012), and the use of broadly-neutralizing antibodies encoded by adeno-associated virus vectors, which are expressed following intramuscular injection and result in secretion of antibody that protects against intravenous or vaginal challenge with HIV (Balazs et al., 2012, 2014). "
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    • "CO2 was used for euthanasia, and all efforts were made to minimize suffering. Human fetal liver samples were obtained via a non-profit partner (Advanced Bioscience Resources, Alameda, CA) without any information that would identify the subjects from whom they were derived and did not require IRB approval for its use, as previously described [37]. "
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    ABSTRACT: In the present study, a novel adeno-associated virus (AAV) vector-mediated gene delivery approach was taken to improve the reconstitution of functional CD8(+) T cells in humanized mice, thereby mimicking the human immune system (HIS). Human genes encoding HLA-A2 and selected human cytokines (A2/hucytokines) were introduced to an immune-deficient mouse model [NOD/SCID/IL2rγ(null) (NSG) mice] using AAV serotype 9 (AAV9) vectors, followed by transplantation of human hematopoietic stem cells. NSG mice transduced with AAV9 encoding A2/hucytokines resulted in higher levels of reconstitution of human CD45(+) cells compared to NSG mice transduced with AAV9 encoding HLA-A2 alone or HLA-A2-transgenic NSG mice. Furthermore, this group of HIS mice also mounted the highest level of antigen-specific A2-restricted human CD8(+) T-cell response upon vaccination with recombinant adenoviruses expressing human malaria and HIV antigens. Finally, the human CD8(+) T-cell response induced in human malaria vaccine-immunized HIS mice was shown to be functional by displaying cytotoxic activity against hepatocytes that express the human malaria antigen in the context of A2 molecules. Taken together, our data show that AAV vector-mediated gene delivery is a simple and efficient method to transfer multiple human genes to immune-deficient mice, thus facilitating successful reconstitution of HIS in mice. The HIS mice generated in this study should ultimately allow us to swiftly evaluate the T-cell immunogenicity of various human vaccine candidates in a pre-clinical setting.
    PLoS ONE 02/2014; 9(2):e88205. DOI:10.1371/journal.pone.0088205 · 3.23 Impact Factor
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    • "The CD8+ T cells that expressed HIV-specific TCR were also able to kill primary CD4+ T cells infected with HIV, suggesting these TCRs can effectively recognize endogenously processed peptides. This approach could be particularly useful in determining efficiency of larger pool of HIV-specific TCRs for optimal T cell vaccine design or for their ability to recognize latently infected CD4+ T cells [4], [5]. "
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