Tail scarification with Vaccinia virus Lister as a model for evaluation of smallpox vaccine potency in mice.
Since smallpox eradication by the WHO during the 1980s, potency of new vaccines is compared to vaccines that were used during the eradication campaign. In this work we characterize the tail scarification technique in mice as a model for scarification in humans. Similar to humans, mice develop "clinical take" which is dependent on the vaccination dose. Appearance of anti-Vaccinia IgM is followed by IgG antibodies 10 days post scarification and lasting more then 1(1/2) years. Mice with "clinical take" are 100% protected against lethal respiratory challenge (100LD(50)) of Vaccinia WR indicating that the "clinical take" can serve as a correlate of protective immunity. Reducing the vaccination dose and using Cowpox virus as a more virulent strain, enabled us to draw the limit of the vaccine potency in mice. Similar to humans, in revaccinated mice the development of "clinical take" was inversely correlated to the level of pre-existing antibodies. These results indicate that tail scarification of mice can be used as a model for evaluation of smallpox vaccines. High correlation between "clinical take" and protective immunity allows the use of visual inspection to evaluate vaccine potency.
Melamed
Sharon
S
Department of Infectious Diseases, The Israel Institute for Biological Research, Israel.
Sharon
Melamed
M
Paran
Nir
N
Nir
Paran
P
Katz
Lior
L
Lior
Katz
K
Ben-Nathan
David
D
David
Ben-Nathan
BN
Israely
Tomer
T
Tomer
Israely
I
Schneider
Paula
P
Paula
Schneider
S
Levin
Reuven
R
Reuven
Levin
L
Lustig
Shlomo
S
Shlomo
Lustig
L
D000818:Animals; D000914:Antibodies, Viral / Q000032:analysis / Q000096:biosynthesis*; D002921:Cicatrix / Q000139:chemically induced*; D004195:Disease Models, Animal; D007928:Lethal Dose 50; D051379:Mice; D012900:Smallpox Vaccine / Q000009:adverse effects* / Q000276:immunology; D013601:T-Lymphocytes / Q000276:immunology; D013623:Tail / Q000187:drug effects* / Q000473:pathology; D014616:Vaccinia virus / Q000276:immunology*
D000914:Antibodies, Viral; D012900:Smallpox Vaccine