In the past decades, significant advances in our understanding of the infection cycle of the HI-Virus have been achieved but a special type of immune cells, resting dendritic cells (DCs) remain as a reservoir of latent HIV infection, which we are currently unable to treat.
One major area of focus has been cellular restriction factors, which can be deployed by cells in order to fight infections by retroviruses such as HIV-1. One of these restriction factors, the cellular dNTP triphosphohydrolase SAMHD1, inhibits retroviral infection by depleting cytosolic dNTP pools and thereby preventing reverse transcription. Another one – cGas - on the other hand is a cellular DNA-sensor which is able to detect the DNA-products of the reverse transcription and activate via the STING protein a lot of different immune responses.
In order to better understand these restriction factors, we will generate HIV reporter viruses encoding immunogenic epitopes, such as OVA, which can then be used to compare the immune response of wildtype DCs, SAMHD1 Knock-out (KO) DCs and cGAS KO DCs upon HIV infection.
We will firstly characterize the different viruses in HIV infectivity assays and analyze the effect of the viruses on the innate immune response upon infection of DCs from WT, SAMHD1 KO mice and cGAS KO mice by qPCR, ELISA, and FACS. In addition, we will use the infected DCs to stimulated HIV-specific CD4+ and CD8+ T cell responses that will be determined by intracellular cytokine staining.
We hope that by the end of this project we will be able to successfully characterize the impact of the different restriction factors on the innate as well as the adaptive immune response and provide a baseline for further investigation into the restriction factors as potential targets in the aim to treat latent HIV infections.