Features | Partner Sites | Information | LinkXpress
Sign In
GLOBETECH PUBLISHING LLC
GLOBETECH PUBLISHING LLC
PZ HTL SA

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
Image: The nano-cocoon drug delivery system is biocompatible, specifically targets cancer cells, can carry a large drug load, and releases the drugs very quickly once inside the cancer cell. Ligands on the surface of the \"cocoon\" trick cancer cells into consuming it. Enzymes (the “worms\" in this image) inside the cocoon are unleashed once inside the cell, destroying the cocoon and releasing anticancer drugs into the cell (Photo courtesy of Dr. Zhen Gu, North Carolina State University).

Novel Anticancer Drug Delivery System Utilizes DNA-Based Nanocapsules

A novel DNA-based drug delivery system minimizes damage to normal tissues by utilizing the acidic microenvironment inside cancer cells to trigger the directed release of the anticancer drug doxorubicin (DOX).... Read more

Lab Technologies

view channel

Experimental Physicists Find Clues into How Radiotherapy Kills Cancer Cells

A new discovery in experimental physics has implications for a better determination of the process in which radiotherapy destroys cancer cells. Dr. Jason Greenwood from Queen’s University Belfast (Ireland) Center for Plasma Physics collaborated with scientists from Italy and Spain on the work on electrons, and published... Read more

Business

view channel

Interest in Commercial Applications for Proteomics Continues to Grow

Increasing interest in the field of proteomics has led to a series of agreements between private proteomic companies and academic institutions as well as deals between pharmaceutical companies and novel proteomics innovator biotech companies. Proteomics is the study of the structure and function of proteins.... Read more
 
Copyright © 2000-2014 Globetech Media. All rights reserved.