Cytomegalovirus (CMV) Laboratory
Cytomegalovirus (CMV)-specific cellular immune responses in hematopoietic cell transplant (HCT) recipients at the City of Hope. In collaboration with the Hematology department, our laboratory has been observing patients undergoing HCT who are at risk for CMV infection and CMV the question of what elements of immunity are most important for protection from CMV infection in the recipient. A non-therapeutic clinical trial followed patients with such assays as: a) tetramer binding assay (TBA) to locate T-cell recognizing the HLA A2 and B7 presenting CMV peptides; this is done in collaboration with our colleagues Simon Lacey and Don Diamond, b) intra-cellular cytokine (ICC) to locate CD4 and CD8 cells that are activated by CMV peptides and releasing interferon-gamma, c) Q-PCR to detect CMV DNA in plasma, and d) presence of PD-1 expression in T-cells, and effect of KIR genotyping on outcome (this was done in collaboration with our colleagues D. Senitzer and J. Sun.
Preliminary data suggests a prominent role for donor KIR genotype in protection from CMV infection and disease (see Figure 1 below). In addition, once CMV reactivation occurs, it is the expression of PD-1 in CD4 and CD8 T-cells, a measure of T-cell exhaustion, which correlates to the development of CMV disease. This study serves as a platform to other very interesting studies at the COH, which involve vaccine development for protection of patients from CMV.
Figure 1: CMV reactivation and infection relative to donor KIR haplotypes. Group I had minimal donor activating KIR genes, Group II had either aKIR 2DS2 or aKIR2DS4, and Group III had both aKIR 2DS2 and aKIR2DS4 or > 5 aKIR genes. Panel A: Time to first CMV positivity by Q-PCR is shown for subjects in each group (Log-Rank test p<0.001). Panel B: Time to peak Q-PCR is shown for subjects in each group (Log-Rank test p<0.001).
Optimized CMV antigens for induction of immunity. Our laboratory has adopted the approach of using HLAA*0201 transgenic mice immunized with recombinant CMV-DNA vectors followed by a boost with rAAV containing a CMV-transgene. This strategy has been very successful in yielding plenty of CMI for the known CMV genes such as pp65 and IE1. Fusion of shorter constructs are now being developed to remove signals that may interfere with peptide presentation (such as the Nuclear Localization Signal-NLS) and to insert multiple targets into one DNA vaccine.
Gene Transfer For HIV-Related Therapy
Treatment of AIDS with genetically modified blood stem cells hypothesizes that genetic modification of cells containing inhibitors of genes important for HIV-1 replication will prevent the progression of HIV-1 in these cell populations and slow the progression to disease. Of the various ways that this could be tested, one approach currently tests whether genetically transduced blood stem cells could repopulate in the host after autologous transplantation and result in mixed blood chimerism (host cells plus genetically modified host cells).
A second approach addresses whether autologous CD4 T-cells can be genetically modified and safely transferred to AIDS patients. We are seeking to answer three important questions: (1) Can lentivirus-transduced cells be safely transplanted into AIDS patients without serious procedure-related morbidity? (2) Which potential HIV targets are most susceptible to a transgene attack? (3) Can a selection system be introduced with the anti-HIV transgenes to produce long-term expression of the transgene?
Cytomegalovirus Infection (CMV)
Despite available antiviral agents for use in prevention of CMV infection after transplantation, the virus remains a problem for efficient patient management after both solid organ and marrow transplantation. The pathogenesis of infection in this setting involves transfer of infection with the transplanted organ or reactivation of endogenous infection. Once infection occurs, CMV encodes several proteins that interfere with antigen processing and HLA-associated transport of peptide epitope to the cell surface, a process necessary for induction of cytotoxic T-lymphocyte (CTL) function. We are studying cellular mechanisms of host protection after stem cell transplantation. Our laboratory is developing new methods of DNA-based immunization for CMV. It is likely that antiviral chemotherapy will not be sufficient to protect immunosuppressed patients from endogenous CMV infection, and it is possible that methods that strengthen the host's resistance to infection will have an increasing role in controlling CMV infection in the future.Cytomegalovirus
AIDS and HIV Laboratory
Ghislaine Hawkins, M.Sc.
Research Associate II
Sr. Administrative Assistant
Research Laboratory Aide
December 01, 2015
January 01, 2015
November 28, 2014
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