Sprouty 1 and 2 Regulation of Cytotoxicity in HIV-specific CD8+ T Cells
The poor cytotoxicity of CD8+ T cells against cells harboring reactivated HIV which have a low expression of viral antigens presents a profound barrier to the success of HIV cure strategies. Discovering new pathways that safely enhance the function of cytotoxic T-lymphocytes (CTLs) has immense potential for harnessing CTLs for the ‘shock and kill’ approach. While in a quiescent state, HIV-infected resting CD4+ T cells do not express sufficient HIV antigens and, thus, are not targeted by CTLs. The ‘shock and kill’ paradigm proposes to combine latency-reversing agents (LRAs) with CTLs to selectively eliminate infected cells. However, current LRA’s are relatively poor inducers of viral antigens and CTLs from cART-treated individuals display limited ex vivo cytotoxicity against reactivated latent cells. The use of rejuvenated CTLs with enhanced functionality to eliminate cells producing low levels of viral antigens, may ultimately lead to a cure for HIV. We identified Sprouty 1 and 2 (Spry1/2) as key negative regulators of the development, function, and recall capacity of CD8+ memory T cells. We have shown that in the absence of Spry1/2, murine CD8+ T cells have enhanced in vivo cytotoxicity and form larger numbers of polyfunctional memory cells. We hypothesize that deletion of Spry1/2 in HIV-specific human CD8+ T cells will enhance their cytotoxicity against autologous target cells expressing HIV-1 viral peptides. We will first delete Spry1/2 in HIV-specific CD8+ T cells using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9. We will next determine if in the absence of Spry1/2, CD8+ T cells will have a lower TCR activation threshold and thus have a heightened sensitivity and cytotoxicity to cells presenting low concentrations of HIV-1 peptides. Completing these objectives will introduce a new paradigm in ensuring the success of the shock and kill approach, ultimately leading to translational efforts towards a cure for HIV.