# Investigation of persistent HIV immune stimulation in lymphoid tissues during therapy as a cause of sustained immune activation

> **NIH NIH R01** · UNIVERSITY OF MINNESOTA · 2024 · $735,152

## Abstract

Antiretroviral therapy (ART) sufficiently suppresses HIV replication to reduce plasma viral load (pVL) below the
limit of detection, but immune activation (IA) is not normalized and the elevated levels of IA markers- IL-6, TNF,
TGFß, C reactive protein (CRP), and D-Dimer remain elevated are associated with increased risk for
cardiovascular disease, endothelial disfunction and clotting abnormalities, pulmonary hypertension, interstitial
nephritis, development of non-AIDS associated malignancies, and CNS abnormalities. Multiple mechanisms
have been proposed to explain the persistence of IA under ART including microbial translocation and herpes
virus infections (e.g., HSV, CMV, EBV). However, here we propose that HIV itself is a major cause of
persistent IA because of ongoing virus production in lymphoid tissues (LT) while on ART. In this revised
proposal, we have one specific aim that tests two hypotheses: 1) Sustained IA during ART is driven by
production of virions and/or expression of viral antigens in reactivated latently infected cells with or without
persistent low-level virus replication; and 2) that persistent low-level virus replication during ART is the result of
intracellular concentrations (IC) of antiretroviral (ARV) drugs in LT that do not completely inhibit replication and
virus production. For our first hypothesis we will seek direct evidence of correlations between persistent IA and
virus production/antigen expression in LT by identification, at the single cell level, of: 1) virus-producing CD4 T
cells lacking markers of activation and proliferation that we have previously shown can sustain low levels of
virus production; 2) T follicular helper cells (Tfh) in B cell follicles that have recently been shown to be an
independent reservoir for viral persistence; and 3) reactivated latently infected T cells producing virus or p24.
We propose investigations of these drivers of IA by our validated and highly sensitive in situ hybridization (ISH)
methods to detect, phenotype and locate virus (v) RNA+ and virus-producing cells in LT; by a validated highly
sensitive high throughput “envelope detection by induced transcription-based sequencing” (EDITS) assay; and
a broadly neutralizing antibody (bNab) method to enrich for HIV-envelope (ENV)+ cells. For the hypothesized
correlations of the virus drivers with IA, we will measure IA with standard flow-based antibody assays and with
single cell transcriptomic analysis of LT mononuclear cells to identify unique gene signatures associated with
IA. Our second hypothesis will be tested by quantification of ARV-intracellular concentrations (ICs) in LT and
determine the relationships among ARV-ICs and the frequency of detecting the three putative virus drivers of
IA. Establishing that HIV itself is a cause of IA would point future developments to fully suppress virus
production in the LT reservoir with benefits both in reducing IA and associated pathologies and as an essential
component of HIV Cure Str...

## Key facts

- **NIH application ID:** 10810857
- **Project number:** 5R01AI147912-05
- **Recipient organization:** UNIVERSITY OF MINNESOTA
- **Principal Investigator:** Timothy W Schacker
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $735,152
- **Award type:** 5
- **Project period:** 2020-04-03 → 2025-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10810857

## Citation

> US National Institutes of Health, RePORTER application 10810857, Investigation of persistent HIV immune stimulation in lymphoid tissues during therapy as a cause of sustained immune activation (5R01AI147912-05). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10810857. Licensed CC0.

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