As patients live longer with HIV-1, non-Hodgkin's lymphoma (NHL) becomes an increasingly important clinical issue. At present, it is the second most common malignancy in HIV-infected adult patients. Approximately 10% (now over 3.5 million worldwide) of HIV-infected patients develop lymphoma. Unfortunately, therapies that would normally be used to combat NHL - chemotherapy, radiation and monoclonal antibodies - can actually hasten progression of HIV disease by exacerbating underlying immunosuppression. Highly active antiretroviral therapy (HAART), which is clearly invaluable, does not halt growth or proliferation of NHL, nor does it offer a definitive cure for HIV. Patients live longer, only to succumb to a malignancy for which few weapons are available. This gap in our clinical armamentarium calls for the development of innovative therapies. The proposed work lays the pre-clinical groundwork for one such novel approach. We hypothesize that bispecific cytotoxic lymphocytes - engineered CTLs that express both a broadly neutralizing antibody (bNAb)/HIV- specific T cell receptor (TCR) fusion protein and a receptor conferring NHL tumor-specificity - can simultaneously eradicate free virus (including escape mutants), HIV-infected cells and the associated deadly cancer. We seek to develop (Aim 1) and characterize (Aim 2) these bispecific cells with the ultimate goal of administering them to HIV-infected patients with NHL as part of a future clinical trial. Building on the observations that bNAbs neutralize over 90% of circulating HIV-1 strains whereas exogenous TCR enhances CTL killing of HIV-infected cells, we will introduce bNAb fused with TCR cloned from rare HIV-specific, cytotoxicity-competent memory CD8+ patient CTLs into non-HIV specific autologous CD8+ CTL. Chimeric antigen receptor (CAR) CAR.CD19 will provide NHL tumor-specificity. The resulting bispecific super-cells will be rigorously tested by conventional immunological approaches and viral inhibition assays for the ability to neutralize free virus, HIV-infected cells (including latently infected cells), and tumor cells. For each engineered clone, the relationship between cytotoxicity and immunological synapse (IS) structure and function will be examined via super-resolution stimulated emission depletion (STED) microscopy. Although other investigators are working on immunotherapeutic strategies for HIV and cancer, the proposed work will be the first to explore the use of a single vector to treat two distinct disease states i an important, increasing population, combining these strategies into a single therapeutic approach. Successful development of these cells would not only provide life-saving therapy for HIV-infected patients with lymphoma, but would provide proof-of-concept for similar multipronged immunotherapy in other disease states where tumors accompany viral infection.
Cytotoxic lymphocytes or 'killer cells' play a critical role in human host defense against viruses and cancer. Here, we propose to develop and characterize bispecific cytotoxic lymphocytes - engineered CTLs that express a broadly neutralizing antibody/HIV-specific receptor chimera as well as a receptor conferring lymphoma-specificity. This novel approach will provide immunotherapy for both the virus and its associated deadly cancer. (End of Abstract)
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