# Macrophage Ontogeny and Polarization in HIV/SIV Infection

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2020 · $767,649

## Abstract

Project Summary
New developments in myeloid cell research have dramatically changed our understanding of
macrophage ontogeny and function. Our decades-long understanding of the origin of macrophages has
been overturned, as we now recognize that some tissue macrophages are not derived from
continuously infiltrating monocytes that mature to macrophages, but rather exist as self-replicating cells
derived from yolk sac progenitors during fetal development. In addition, within each one of these
ontogenically distinct populations, there exist specific functional phenotypes that are polarized in
response to signaling molecules in the extracellular milieu. We have novel data showing that peritoneal
macrophages and microglia harbor transcriptional competent SIV genomes in infected macaques that
have been virally suppressed by combination antiretroviral therapy (cART) for more than 500 days p.i.
These findings suggest that some specialized macrophages represent a different type of viral reservoir
with unique traits. Latency studies, however, have focused on resting CD4+ T cells, and little is known
about the mechanisms that modulate latency and reactivation in other cell types also susceptible to HIV
infection. Therefore, we propose to: 1) Characterize tissue macrophages in the context of ontogeny and
polarization in uninfected, SIV-infected, and SIV-infected cART-treated macaques; 2) Develop in vitro
models in macaque and human primary tissue macrophages and monocyte-derived macrophages for
the characterization of mechanisms associated with viral latency and reactivation.

## Key facts

- **NIH application ID:** 9931137
- **Project number:** 5R01AI127142-05
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** JANICE E CLEMENTS
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $767,649
- **Award type:** 5
- **Project period:** 2016-06-15 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9931137

## Citation

> US National Institutes of Health, RePORTER application 9931137, Macrophage Ontogeny and Polarization in HIV/SIV Infection (5R01AI127142-05). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/9931137. Licensed CC0.

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