Our long term goal is to build an HIV-resistant immune system. Based prior studies in the field of the immunopathogenesis of HIV infection, it is likely that both enhanced HlV-specific immunity, as well as a population of CD4 cells that have enhanced resistance to HIV infection will be required to achieve this goal. In our ongoing IPCP grant (expiry February 2009), in collaboration with Sangamo Biosciences, we have developed HIV resistant CD4 T cells using zinc finger nucleases to knock out the CCR5 coreceptor, which is being tested in the clinic in 2009 (Perez et al, in press). To generate enhanced HlV-specific immunity, in collaboration with Adaptimmune Ltd, we developed HIV gag specific TCRs, a strategy that has recently also shown promise in cancer immunotherapy (Varela et al, in press). The elements of our proposal are: Engineering Elite Control of HIV Infection (Project 1, Jakobsen [Adaptimmune]): This project will clone new HIV-1 specific TCRs, affinity enhance them for improved function, and test specificity and efficacy, and viral evolution/escape (Core C) in vitro and in vivo in the NOG mouse model (Core B). Clinical Trials to Evaluate the Safety and Antiviral Effects of High Affinity Gag Specific CTLs and CCR5- deficient CD4 Cells in HIV/AIDS (Project 2, June [Penn]): This project will test the safety of natural and high affinity HIV specific TCRs in clinical trials, and if safe, evaluate their relative efficiencies via competitive repopulation;in years 4 and 5 we will carry out a second trial combining redirected CTLs with HIV resistant CD4 T cells. Effects on viral evolution (Core C) and HIV specific immunity (Core B) will be studied, along with continued investigation in lentiviral vector integration site analysis (Core A). Zinc Finger Nucleases to Specifically Disrupt HIV Coreceptor Expression (Project 3: Doms [Penn] and Perez [CHOP]). This project will utilize the Sangamo zinc finger nuclease technology to study the effects of CCR5 and CXCR4 knock out in T cells and stem cells, and antiviral effects and viral evolution in vitro and in vivo in the NOG animal model (Cores B and C). The Program is supported by 3 Cores: Core A is the administrative Core (PI, June);Core B is the Novel Immune Assessment and Mouse Core (PI, Riley);and Core C is the Sequencing and Viral Evolution Core (PI, Bushman). In addition, our Program takes advantage of existing School of Medicine (Clinical Cell and Vaccine Production Facility and Human Immunology Core) and CFAR Cores to promote cost sharing and avoid duplication of resources.
Both the quality of life and economic burdens on the health care system would be improved by obviating the need for patients with HIV infection to take daily antiviral medications. In this proposal we investigate how to genetically engineer a subject's own immune system to teach it how to fight HIV. The scientific principles evaluated in our Program are broadly applicable to other diseases, such as cancer and chronic infection. PROJECT 1: Engineering Elite Control of HIV-1 Infection (Jakobsen, B) PROJECT 1 DESCRIPTION (provided by applicant): While maturing, T cells undergo a massive, largely random rearrangement of their T cell receptor (TCR) genes, resulting in a near unique antigen specificity for each T cell in the body. When a pathogen such as HIV-1 enters the body, T cells recognizing HIV-1 antigens are expanded and a select number of these T cells become overrepresented or immunodominant. However, the ability of these immunodominant HIV-1 specific CDS T cells to control HIV-1 replication varies considerably amongst individuals, and these differences play a major role in determining the rate of disease progression. Individuals able to mount multiple responses targeting HIVGAG have reduced viral loads. Of note, a majority of """"""""elite controllers"""""""" express HLA-B alleles associated with potent anti-HIVGAG responses, suggesting that in rare cases effective CDS T cell responses can control HIV-1 infection. However, not all T cell responses targeting HIVGAG are protective and there is no consensus on why this is. Providing insight into why one HIV-1 specific T cell response is more effective than another is a major goal of this project. One way to determine whether one T cell is able to function better than another is to perform population studies in which the presence of a particular T cell response is correlated with viral load. While informative, these studies do not shed light onto why one response is better than another. In vitro studies using HIV-1 specific T cells isolated from individuals indicate that T cells with a higher functional avidity function to control HIV-1 infection better than those with a lower functional avidity, though region of HIV-1 targeted also is important. However, there are several confounding factors including the differentiation state of the T cells and the expression of co-stimulatory and adhesion molecules that preclude direct correlations of functional avidity and TCR affinity. In this application we propose model systems that will permit direct comparison of various HIV-1 specific TCRs and functional avidity through unique proprietary approaches to increase the affinity of natural HlV-specific TCRs and test such responses in vitro and in vivo.
We predict that these studies will confirm our central hypothesis that non-protective T cell responses such as those that are HLA-A2 restricted can be converted into protective T cell response by engineering higher TCR affinity. Similarly, we aim to investigate whether the introduction of T cells that recognize multiple HIV-1 antigens with high affinity will render HIV-1 sufficiently crippled so that escape does not occur, enabling elite control of HIV-1 infection by autologous T cell transfer.
Showing the most recent 10 out of 14 publications
