Tumor-Like Tissue Microenvironments Could Hold Clues to Curing HIV, Northwestern Study Finds

The tissue microenvironments surrounding HIV (搜索)搜索该疾病-infected immune cells bear a striking resemblance to those surrounding cancerous tumors, according to a new Northwestern University查看公司主页 study published August 4 in the journal Frontiers in Immunology. The findings offer a novel explanation for why HIV has proven so difficult to cure and suggest that future HIV cure strategies may benefit from approaches traditionally used in cancer therapy.

Scientists found that viral reservoirs — the small pockets of virus that remain hidden in the body after treatment and can reignite infection if therapy is stopped — exist within tissue microenvironments that resemble immune-suppressive tumor microenvironments. By integrating molecular imaging, spatial transcriptomics, and machine learning, the research team created a detailed map of the viral microenvironment in animal models with Simian Immunodeficiency Virus (搜索)搜索该疾病 (SIV), a commonly used proxy for HIV (搜索)搜索该疾病, and identified shared biological programs between viral persistence and tumor immune evasion.

"We are interested in the similarities with cancer because to cure any type of cancer, you need to deal with a series of factors, not just one thing," said corresponding author Ramon Lorenzo-Redondo, PhD, assistant professor of medicine in the Division of Infectious Diseases at Northwestern University查看公司主页 Feinberg School of Medicine. "We are now trying to understand the chain of events that leads to that environment to then target all the components of this multi-component, multi-systemic problem."

A Sanctuary for Viral Persistence

The resemblance to cancer emerged from the scientists' effort to better understand viral reservoirs. These reservoirs create what Lorenzo-Redondo described as a "sanctuary-type environment" that allows the virus to survive while simultaneously blocking the immune cells meant to eliminate it.

"We think the virus promotes a whole sanctuary-type environment that allows it to survive, but also, because it's immune exclusive, it stops the cells that are supposed to kill the virus," Lorenzo-Redondo said. "As soon as you remove treatment, because these populations are ready to go and cannot be cleared, they again trigger a chain of events that will infect other cells."

Zooming Out: From Infected Cells to the Tissue Neighborhood

Unlike previous studies that focused on identifying the specific cells that harbor HIV (搜索)搜索该疾病, this investigation examined the broader tissue microenvironment to understand why reservoirs persist for decades. Lorenzo-Redondo used an analogy to explain the approach: "Imagine the infected cell is a beautiful house, set near the beach with a stunning mountain view. If you change the neighborhood — build a highway through it, remove what makes it desirable — you make it much harder for anyone to stay. Our goal is to understand how to reshape that neighborhood so the immune system can move in, break down these reservoirs and finally do its job."

The findings lay critical groundwork for future HIV (搜索)搜索该疾病 cure strategies aimed not only at eliminating infected cells, but also at disrupting the environments that protect them and make viral persistence possible.

Gut Tissue Analysis Reveals Tumor-Like Characteristics

The tumor-like characteristics became apparent only when the scientists examined SIV reservoirs within gut tissue, where most persistent virus survives during therapy. This represented a significant departure from previous research that focused primarily on blood samples.

Two Northwestern labs approached the problem in complementary ways. Co-corresponding author Thomas J. Hope, PhD, professor of Cell and Developmental Biology and of Obstetrics and Gynecology, likened the collaboration to reconstructing events at a party. His lab's imaging methods provided snapshots of what is happening in tissues at a given moment, while Lorenzo-Redondo's computational analyses revealed the relationships and interactions occurring behind the scenes.

"With imaging, we're taking snapshots of the party," Hope said. "We can see who's there, where they are and what's happening in that moment. But Ramon can use these large-scale sequencing datasets to figure out who was talking to whom, what groups formed and how the interactions changed over time."

Using a novel imaging and spatial transcriptomics platform that combines immunoPET/CT-guided tissue mapping with high-resolution genomic analysis, the scientists — led by Eliana Crentsil, a graduate student in Hope's and Lorenzo-Redondo's labs — located and analyzed rare sites of viral persistence within tissues in the guts of non-human primate animal models.

"When two completely different approaches keep pointing to the same conclusion, it gives you a lot of confidence that you've uncovered something real," Hope said. "In our case, both approaches pointed to HIV (搜索)搜索该疾病 reservoirs existing within tissue environments that resemble those seen in difficult-to-treat cancers."

Cold and Hot Reservoirs: Divergent Immune Profiles

The team observed that the collection of cells, signals, and tissues surrounding viral reservoirs — termed the viral microenvironment (VME) — shares important features with so-called "cold" tumor microenvironments (TME), which are known to suppress immune responses and resist clearance by the body's defenses.

Persistent reservoirs that shared features with "cold" tumors showed increased activity in biological pathways linked to tissue remodeling and immune suppression. In contrast, short-lived reservoirs more closely resembled "hot" tumors, which attract stronger immune responses and showed higher levels of immune cells capable of killing infected cells. The scientists also found that regulatory T cells, which help control immune activity, played a central role in the cell-to-cell communication networks around viral reservoirs.

Using machine learning, the team identified several human genes — including KRT8 (搜索)搜索该靶点, EPCAM (搜索)搜索该靶点, and RRM2 (搜索)搜索该靶点 — as important contributors to the tumor-like features seen in persistent viral reservoirs.

Together, the findings suggest HIV (搜索)搜索该疾病 persistence depends not only on infected cells, but also on the tissue environments that shield them. By disrupting those protective environments, researchers may eventually make viral reservoirs more vulnerable to immune attack, much as cancer therapies seek to overcome immune-suppressive tumor microenvironments.

The study, titled "A tissue microenvironment analogous to certain tumor microenvironments facilitates HIV (搜索)搜索该疾病 persistence," was supported by the National Institute of Allergy and Infectious Diseases of the National Institutes of Health. Other Northwestern authors include Natalie Stegman and Thomas Hope.