# Scientists discover “footprints of death” that viruses may use to spread

> Researchers at La Trobe University have identified a hidden process that unfolds as cells die. The study, published in Nature Communications, describes tiny "footprints of death" that mark where a dying cell once sat and may help the immune system clean up...

Canonical URL: https://www.argo.net/scientists-discover-footprints-of-death-that-viruses-may-use-to-spread/
Byline: La Trobe University
Published: 2026-07-11T05:00:05+00:00
Categories: Health

![Fluorescent microscopy image showing apoptotic extracellular vesicles from dying cells](https://www.argo.net/wp-content/uploads/2026/06/Scientists_discover_footprints_of_death_that_viruses_may_use_to_spread.jpg)

Researchers at [La Trobe University](https://www.latrobe.edu.au/news/articles/2025/release/footprint-of-death-gives-new-clues-to-cell-life) have identified a hidden process that unfolds as cells die. The study, published in Nature Communications, describes tiny "footprints of death" that mark where a dying cell once sat and may help the immune system clean up cellular remains.

The finding adds a surprising twist to one of the body's most routine jobs. Billions of cells die each day as tissues renew themselves and respond to disease. According to the research team, this final stage is highly organized and may also create opportunities for **influenza viruses** to move into nearby cells.

The work was led by PhD candidate **Stephanie Rutter** in the laboratory of Professor **Ivan Poon** at the La Trobe Institute for Molecular Science. Collaborators from WEHI and Toronto Metropolitan University also contributed to the research.

## A hidden trail left by dying cells

When cells reach the end of their life, many enter a controlled self-destruction program called apoptosis. This process helps the body remove worn out or damaged cells while limiting harm to surrounding tissue. It also gives immune cells clear instructions about what should be cleared away.

In the new study, the researchers watched dying cells change shape and pull away from the surface beneath them. As the cells detached, they left behind a residue that the team named the **FOotprint Of Death**, or FOOD. This leftover material was more than a smear of cell debris. It contained structures that appeared to carry useful signals.

The researchers found that this footprint forms as the dying cell retracts. The material remains attached to the surface and marks the place where the cell died. That location signal may help cleanup cells find the remaining fragments before they linger in tissue.

Professor Poon said the discovery changes how researchers can think about the final moments of a cell. "Our findings demonstrate the complexity of this process," he said.

## New vesicles at the death site

Inside the footprint, the team identified a new type of extracellular vesicle. Extracellular vesicles are tiny packages released by cells. They can carry proteins, fats, DNA and RNA, which makes them important messengers in the body.

The newly described vesicles are called **F-ApoEVs**, short for FOOD-derived apoptotic extracellular vesicles. They are relatively large for vesicles and remain close to the site of cell death. In the study, they formed as the footprint material rounded into small packages after the cell pulled away.

This matters because the body depends on fast cleanup after apoptosis. Dead cell fragments can contain molecules that trigger inflammation if they remain in place too long. The researchers found that F-ApoEVs carry signals that can help immune cells recognize where cleanup is needed.

In simple terms, these vesicles act like biological breadcrumbs. They appear to mark a location and help direct the immune system toward the remains of a dying cell. That signal could help the body recycle cellular material more efficiently.

The discovery also highlights how much remains to be learned about **cell death**. Apoptosis has been studied for decades, yet this footprint-based process had remained unseen until the team followed the physical steps in detail.

## How influenza may use the cleanup signal

The most unexpected result came when the researchers studied cells infected with influenza. In laboratory experiments, viral particles appeared inside the F-ApoEVs. That finding suggests a possible route by which viruses could use normal cleanup machinery to reach neighboring cells.

The work was performed in cells, so the result should be read carefully. It shows a plausible mechanism under experimental conditions. Further studies would be needed to learn how much this process contributes to infection inside the body.

Still, the idea is striking. A vesicle that helps immune cells detect a death site could also carry viral material. If a nearby cell takes up that package, the virus may gain another way to spread while traveling inside a structure produced during normal cell disposal.

Rutter said the result stood out because the team expected the vesicles to support cleanup. "What we didn't expect was how viruses can also take advantage of this process and cause infection by hiding in F-ApoEVs," she said.

For infectious disease research, that makes the footprint a possible new place to look. Scientists often focus on how viruses enter cells and replicate inside them. This study points to the moments after an infected cell dies as another stage that may shape infection.

## Why immune cleanup matters

Every day, the immune system clears dead cells without triggering a major alarm. That quiet removal is essential for healthy tissues. It also helps the body avoid unnecessary inflammation.

When cleanup goes wrong, dead cell fragments can remain in tissue and provoke immune reactions. The La Trobe announcement notes links to inflammatory and autoimmune diseases such as systemic lupus erythematosus. In such conditions, the immune system may respond to material that should have been removed cleanly.

F-ApoEVs may help explain one part of that cleanup pathway. By marking the death site, they could help immune cells locate debris before it causes trouble. The finding suggests that dying cells continue to send signals even after their main structure has broken apart.

Dr. **Georgia Atkin-Smith** of WEHI described the broader implication in vivid terms. "Dying cells can continue to communicate from the grave and may impact immune function," she said.

That communication is central to the discovery. A cell's death can influence surrounding tissue through vesicles, surface signals and immune-cell responses. The new study gives researchers another piece of that signaling network.

## What the finding could mean for treatments

The immediate value of the work is basic biological insight. It shows that dying cells form a distinct footprint and generate vesicles from that footprint. It also suggests that viruses may exploit those vesicles under some conditions.

Over time, the discovery could guide new strategies for infectious disease and immune disorders. If researchers can learn how F-ApoEVs are made, they may be able to influence cleanup signals. That could help the immune system remove dead cells more effectively or limit viral spread through these packages.

Professor Poon said the work could open fresh research directions. "Understanding this basic biological process could open new avenues of research to develop new treatments," he said.

Rutter also framed the discovery as a step toward better disease biology. "The more we can understand about cell death, the better we can understand disease pathologies," she said.

For now, the findings remain early-stage and rooted in cellular experiments. Their strength lies in revealing a hidden process that happens during one of life's most common events. Cells die constantly and their final traces may carry messages that matter for immunity, inflammation and infection.