Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING
GLOBETECH PUBLISHING
JIB

Creation of a Weakly Virulent Strep A Mutant May Boost Vaccine Development

By BiotechDaily International staff writers
Posted on 23 Jun 2014
Image: Electron micrograph, false color, of group A Streptococcus bacteria (Photo courtesy of the University of California, San Diego).
Image: Electron micrograph, false color, of group A Streptococcus bacteria (Photo courtesy of the University of California, San Diego).
Creation of a mutated variety of Group A Streptococcus (GAS) bacteria with reduced virulence but complete immunological expression may pave the way for development of a safe vaccine to prevent infections such as strep throat, necrotizing fasciitis, and rheumatic heart disease, which are caused by these organisms.

All GAS serotypes express the Lancefield group A carbohydrate (GAC), comprising a polyrhamnose backbone with an immunodominant N-acetylglucosamine (GlcNAc) side chain, which is the basis of rapid diagnostic tests. No biological function has so far been attributed to this conserved antigen.

Investigators at the University of California, San Diego (USA) recently identified the genetic locus for GAC and used this knowledge to create a strep A mutant that lacked the GlcNAc side-chain addition. They reported in the June 11, 2014, issue of the journal Cell Host & Microbe that this mutant was significantly less virulent than the wild type organism in two infection models, in association with increased sensitivity to neutrophil killing, platelet-derived antimicrobials in serum, and the antimicrobial peptide LL-37.

The investigators also showed that antibodies to GAC lacking the GlcNAc side chain and containing only polyrhamnose promoted killing of multiple GAS serotypes and protected against systemic GAS challenge after passive immunization.

These findings demonstrated that the Lancefield antigen played a functional role in GAS pathogenesis, and that a deeper understanding of this unique polysaccharide has implications for vaccine development.

“It is satisfying to find that a fundamental observation regarding the genetics and biochemistry of the pathogen can have implications not only for strep disease pathogenesis, but also for vaccine design,” said senior author Dr. Victor Nizet, professor of pediatrics and pharmacy at the University of California, San Diego.

“Most people experience one or more painful strep throat infections as a child or young adult. Developing a broadly effective and safe strep vaccine could prevent this suffering and reduce lost time and productivity at school and work, estimated to cost two billion USD annually.”

Related Links:
University of California, San Diego



comments powered by Disqus

Channels

Drug Discovery

view channel

Ibuprofen May Restore Immune Function in Older Individuals

New research suggests that macrophages from the lungs of old mice respond differently to infections than those of young mice, and ibuprofen given to the mice reversed these changes. New research using lab mice suggests that the solution to more youthful immune function might already be a common over-the-counter pain reliever.... Read more

Therapeutics

view channel
Image: Hair follicle (blue) being attacked by T cells (green) (Photo courtesy of Christiano Lab/Columbia University Medical Center).

Hair Restoration Method Clones Patients’ Cells to Grow New Hair Follicles

Researchers have developed of a new hair restoration approach that uses a patient’s cells to grow new hair follicles. In addition, the [US] Food and Drugs Administration (FDA) recently approved a new drug... Read more

Lab Technologies

view channel
Image: Leica Microsystems launches the inverted research microscope platform Leica DMi8 (Photo courtesy of Leica Microsystems).

New Inverted Microscope Designed to Readily Adapt to Changing Research Demands

A new inverted microscope for biotech and other life science laboratories was designed to readily accommodate modifications and upgrades to allow it to keep current with changing research demands and interests.... Read more

Business

view channel

Partnership Established to Decode Bowel Disease

23andMe (Mountain View, CA,USA), a personal genetics company, is collaborating with Pfizer, Inc. (New York, NY, USA), in which the companies will seek to enroll 10,000 people with inflammatory bowel disease (IBD) in a research project designed to explore the genetic factors associated with the onset, progression, severity,... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.