Feodorova V.A., Pan’kina L.N., Savostina E.P., Sayapina L.V.,
Motin V.L., Dentovskaya S.V., Shaikhutdinova R.Z., Ivanov S.A., Lindner B., Kondakova A.N.,
Bystrova O.V., Kocharova N.A., Senchenkova S.N., Holst O., Pier G.B., Knirel Y.A., Anisimov A.P. |
|
Abstract
The lpxM mutant of the live vaccine Yersinia pestis EV NIIEG strain synthesising a less toxic penta-acylated lipopolysaccharide was found to be avirulent in mice and guinea pigs, notably showing no measurable virulence in Balb/c mice which do retain some susceptibility to the parental strain itself. Twenty-one days after a single injection of the lpxM-mutant, 85-100% protection was achieved in outbred mice and guinea pigs, whereas a 43% protection rate was achieved in Balb/c mice given single low doses (10(3) to 2.5 x 10(4) CFU) of this vaccine. A subcutaneous challenge with 2000 median lethal doses (equal to 20,000 CFU) of fully virulent Y. pestis 231 strain, is a 6-10-fold higher dose than that which the EV NIIEG itself can protect against. |
