Scientists at Israel’s Weizmann Institute have discovered that the so-called “garbage” of cells can kill microbes and may be the body’s own alternative to antibiotics.

The discovery began with a team of researchers studying the proteasome, a protein complex present in nearly all cells.

The proteasome is often referred to as the “garbage can” of the cell because its primary function is to break down unnecessary proteins.

The team, led by Prof. Yifat Merbl of the Weizmann Institute of Science, was not initially focused on finding microbe-killing capabilities in cells but was instead engaged in other research.

“We weren’t even studying microbes at first,” Merbl told Globes. “We were focused on how the breakdown process changes in diseases like cancer or autoimmune disorders.”

The researchers discovered alterations not only in the products broken down, but also in the proteasome itself, which had changed and seemed to wear a different “cap”—a regulatory unit that alters what proteins it breaks down and how.

Usually, the proteins the proteasome breaks down are recycled or serve as a warning of disease to the immune system.

However, when the “cap” changes, it can mask these signals, which can cause cancer and other diseases to go undetected.

The team also noticed that when the proteasome broke down proteins, the result was antimicrobial fragments.

“These were known antimicrobial fragments,” said Merbl. “At first, we found a few. Then dozens. Then 273.”

The researchers had previously observed these antimicrobial fragments but had not yet linked them to the proteasome.

In their research, the team also discovered hundreds of thousands of new antimicrobial fragments, which could pave the way for the development of an alternative to conventional antibiotics for treating infections.

The team discovered that these fragments, when broken down by the proteasome, were as effective as antibiotics in fighting microbes.

These fragments may also provide solutions to those who are allergic or sensitive to antibiotics.

“We’re just scratching the surface,” said Merbl. “There may be similar systems for fighting viruses or fungi. We’ve only just begun to understand the proteasome’s full role in immunity and disease.”

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