Phage proteases activate bacterial antiviral defense by cutting a host sensor

Research published in Science describes how bacteria detect certain bacteriophage infections through the activity of a viral enzyme. The study examined CBASS, an antiviral immune system that can cause infected bacteria to self-destruct, limiting viral spread to neighboring cells. Understanding these defenses could help researchers address bacterial resistance to phages being investigated as treatments for antibiotic-resistant infections.

The researchers found that a protease produced by certain phages cuts a bacterial sensor protein, activating the CBASS signaling pathway. This mechanism detects viral protein activity against a host protein rather than directly recognizing viral genetic material. The supplied account does not report bacterial species, experimental sample sizes or quantitative effect estimates.

The findings identify a potential consideration for designing therapeutic phages that evade bacterial defenses; they do not establish improved treatment outcomes. CBASS is also related to a human immune pathway, making the mechanism relevant to basic immunity research, although implications for human disease remain untested in the supplied report. This account is based on University of Utah Health materials describing the Science paper, “Phage proteases activate CBASS antiphage immunity.” Support included NIH and nonprofit funding.