Send to

Choose Destination
Vaccine. 2006 Feb 13;24(7):989-96. Epub 2005 Sep 6.

Grey variants of the live vaccine strain of Francisella tularensis lack lipopolysaccharide O-antigen, show reduced ability to survive in macrophages and do not induce protective immunity in mice.

Author information

Defence Science and Technology Laboratory, Salisbury, Wiltshire, UK.


Francisella tularensis live vaccine strain (LVS) produces two colony types when grown on solid media, often referred to as blue variants (BV) and grey variants (GV). Whereas blue variant bacteria possessed a lipopolysaccharide O-side chain, grey variant bacteria lacked O-side chains. Grey variant bacteria appeared in stationary phase bacterial cultures and could be identified using a novel FACS-based assay. Compared to blue variant bacteria, grey variants showed a reduced ability to infect and survive in macrophages. The immunisation of mice with blue variant bacteria, but not grey variant bacteria, induced protective immunity towards fully virulent F. tularensis.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center