P. Russell et al., A COMPARISON OF PLAGUE VACCINE, USP AND EV76 VACCINE-INDUCED PROTECTION AGAINST YERSINIA-PESTIS IN A MURINE MODEL, Vaccine, 13(16), 1995, pp. 1551-1556
The median lethal dose (MLD) of a pathogenic strain of Yersinia pestis
was established by three routes of administration in three strains of
mouse. There was no significant difference between the MLDs in the di
fferent strains of mouse. The MLD by the subcutaneous route in Balb/C
and an outbred line was approximately I c.f.u., the MLD following intr
aperitoneal administration was tenfold higher. There were significant
differences in the mean times to death after administration of the cha
llenge by different routes. The relative efficacy of a live attenuated
vaccine strain of Y. pestis (EV76),was compared with that of the form
aldehyde-killed vaccine (Plague vaccine, USP). EV76 protected against
high challenge doses (up to 5.75 x 10(6) MLD), though immunized animal
s showed side effects of varying severity. The killed vaccine was less
effective in terms of dose-protection (deaths occurred after challeng
e with 4000 MLD) and several of the vaccinated animals suffered sub-le
thal, plague-related sequelae to the challenge.