A potentially lethal bacterium protects itself by causing immune tunnel vision, according to a study from scientists at the University of Chicago published in the Journal of Experimental Medicine. By tricking the immune system into focusing on one bug-associated factor, the bacterium Staphylococcus aureus dodges the production of antibodies that would otherwise protect against infection.
Staphylococcus aureus accounts for roughly 20 percent of hospital-acquired blood infections, and antibiotic-resistant strains of the bug (MRSA) are on the rise. Unfortunately, efforts to protect people against Staph infections using vaccines have been largely unsuccessful. Studies in mice have shown that protection against Staph infection depends on the production of antibodies. Although several bacterial proteins can be recognized by human antibodies, these antibodies are often not enough to fight off infection or prevent re-infection.
Patrick Wilson and colleagues now find that although circulating antibodies in people infected with Staph aureus are capable of recognizing a broad range of bacterial proteins, the active immune response is focused on only one-protein A (SpA).
Antibody producing B cells express highly variable receptors on their surface, and normally only a few B cells are capable of recognizing a given molecule (“antigen”), often part of an invading pathogen. When a B cell encounters its specific antigen, it fine-tunes its surface receptor for better, faster recognition the second time around. But SpA acts as a “superantigen,” meaning that it binds to and activates many B cells regardless of their receptor specificity. Once activated, some of the B cells in Staph-infected people appeared to tune their receptors to recognize SpA rather than their intended antigens. This may allow the bug to overpower B cells that might otherwise generate protective antibodies specific for other bacterial components.
It’s not clear why antibodies against SpA are not protective, but these data suggest that future vaccine approaches must be designed to side-step this bacterial subterfuge.
Reference: Pauli NT, et al. 2014. J. Exp. Med. doi:10.1084/jem.20141404
Source: Rockefeller University Press
Beyond the Surface: Rethinking Environmental Hygiene Validation at Exchange25
June 30th 2025Environmental hygiene is about more than just shiny surfaces. At Exchange25, infection prevention experts urged the field to look deeper, rethink blame, and validate cleaning efforts across the entire care environment, not just EVS tasks.
A Controversial Reboot: New Vaccine Panel Faces Scrutiny, Support, and Sharp Divides
June 26th 2025As the newly appointed Advisory Committee on Immunization Practices (ACIP) met for the first time under sweeping changes by HHS Secretary Robert F. Kennedy Jr, the national spotlight turned to the panel’s legitimacy, vaccine guidance, and whether science or ideology would steer public health policy in a polarized era.
Getting Down and Dirty With PPE: Presentations at HSPA by Jill Holdsworth and Katie Belski
June 26th 2025In the heart of the hospital, decontamination technicians tackle one of health care’s dirtiest—and most vital—jobs. At HSPA 2025, 6 packed workshops led by experts Jill Holdsworth and Katie Belski spotlighted the crucial, often-overlooked art of PPE removal. The message was clear: proper doffing saves lives, starting with your own.