Poster Presentation Second Round 16th Lorne Infection and Immunity 2026

Macrophage heterogeneity influences cellular response to HIV infection and latency modulation (#114)

Laura Rikard-Bell 1 2 , Michelle E Wong 1 3 , Salimeh Ebrahimnezhaddarzi 1 , Morgane Brunton-O’Sullivan 1 , Betty Kouskousis 1 , Mark Ziemann 1 4 , Anthony Jaworowski 1 5 6 , Anna C Hearps 1 5 7
  1. Life Sciences Discipline, Burnet Institute, Melbourne, VIC, Australia
  2. School of Translational Medicine, Monash University, Melbourne, VIC, Australia
  3. Department of Microbial Pathogenesis, Yale University School of Medicine, New Haven, Connecticut, USA
  4. School of Life and Environmental Sciences, Deakin University, Geelong, Victoria, Australia
  5. Department of Infectious Diseases, Monash University, Melbourne, VIC, Australia
  6. School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
  7. Department of Infectious Diseases, University of Melbourne, Melbourne, VIC, Australia

Background

HIV infection of various macrophage types contributes to viral reservoirs that persist in people with HIV despite antiretroviral therapy and preclude HIV cure. Factors governing the establishment and reversal of HIV reservoirs in different macrophage types remain poorly understood but are crucial for the design of strategies to eliminate this important HIV reservoir.

 

Methods

Primary human monocytes were differentiated into monocyte-derived macrophages (MDM) and alveolar-like (AlvMDM) macrophages, infected with an HIV-GFP reporter virus, and applied to an in vitro HIV latency model. To investigate transcriptional changes associated with latency, macrophages were FACS sorted and subjected to single-cell RNA sequencing. Expression of HIV RNA identified populations of latently-infected macrophages in GFP- cells, and differential gene expression and pathway enrichment analyses were performed.

 

Results

Rates of stochastic HIV latency reactivation were comparable between MDM and AlvMDM (p=0.284). Toll-like receptor agonists stimulating TLR2, 3, 4, or 7/8 inhibited HIV reactivation in latently-infected AlvMDM (all, p<0.05), but not MDM. Latently-infected macrophages identified as GFP- but expressing HIV RNA had altered expression of genes related to cell cycle/division and protection from apoptosis, as well as upregulated expression of genes encoding cell surface receptors, including STAB1 and TNFRF9, on MDM and AlvMDM, respectively. Transcriptional profiling indicated considerable differences between macrophage types in the extent and nature of their response to latent and productive infection, with HIV infection having a greater impact on AlvMDM. Enrichment of proteasome-related pathways was more prominent in HIV-infected MDM, whilst AlvMDM exhibited greater transcriptional changes related to immune and viral responses.

 

Conclusions

Substantial differences exist between macrophage types regarding their susceptibility to latency reversal and cellular response to productive HIV infection. Further, latently-infected macrophages exhibit unique transcriptional changes that differ by macrophage type. These findings have implications for developing strategies targeting latently-infected macrophages across tissue sites to eliminate HIV.