Project 1

Summary Project 1 HLA-E is a non-polymorphic HLA class I molecule that preferentially binds to a conserved nonamer peptide from the signal sequences of HLA-A/B/C/G to regulate NK cell function via interactions with CD94/NKG2A/C receptors. HLA-E also binds sequence diverse pathogen peptides at low affinity, which can be recognised by specific T cells. Recently, Louis Picker and colleagues showed that a particular rhesus cytomegalovirus-based vaccine primed MHC-E restricted T cells that cleared challenge SIV in >50% of monkeys. This raises the possibility that similar T cells in humans might clear HIV-1 infection. In addition to our extensive structural evaluation of HLA-E, we have recently shown that HLA-E exists in peptide receptive forms in solution allowing low affinity binding of peptides. Our discoveries to enhance stable peptide binding and to generate improved HLA-E tetramer reagents, have enabled us to prime human T cells from healthy people in vitro, to isolate T cell clones specific for three epitopes and to show these T cells kill HIV-1 infected cells. In this project using lentiviral transduction, we will transfer the TCRs from these clones into third party CD8 T cells, initially from HIV negative blood donors. We will characterize the anti-HIV potential of the TCR transduced T cells in vitro and select the best for in vivo studies in HIV-1 infected BLT mice (Project 3). We aim to extend our initial observations that these T cells alone can suppress virus RNA load tenfold and significantly reduce DNA provirus load. In vitro and in vivo we will compare HLA-E restricted T cells with classical HLA A*02:01 or B*57:01 restricted T cells specific for the same peptides in order to show whether HLA-E restricted T cells have potential therapeutic advantages beyond their universality. With T-Cypher, using proprietary technology, we will make high affinity TCR mutants to determine whether this improves their antiviral properties compared to the parent TCRs. In collaboration with Project 2 we will use antibodies specific for HLA-E-VL9 to block the HLA-E interaction with CD94-NKG2 receptors and enhance T cell function in vitro and in vivo. We will also compare TCR transduced T cells with chimeric TCR mimic antibody-transduced T cells to evaluate their anti-HIV functions in vitro and in vivo. Thus, we aim to determine the most effective way of harnessing HLA-E restricted, anti-HIV immune responses to suppress virus replication in ways that could lead universal HLA unrestricted therapy as a route to HIV cure.