Study findings from LigoCyte Pharmaceuticals Inc. broaden understanding of anthrax vaccines
December 15th, 2008
2008 DEC 15 -- Scientists discuss in 'A single immunization with a dry powder anthrax vaccine protects rabbits against lethal aerosol challenge' new findings in anthrax. "Here we confirm that intranasal (IN) dry powder anthrax vaccine formulations are able to protect rabbits against aerosol challenge 9 weeks after a single immunization. The optimum dose of rPA in our dry powder anthrax vaccine formulation in rabbits was experimentally determined to be 150microg and therefore was chosen as the target dose for all subsequent experiments," investigators in the United States report.
"Rabbits received a single dose of either 150microg rPA, 150microg rPA+150microg of a conjugated 10-mer peptide representing the Bacillus anthracis capsule (conj), or 150microg of conj alone. All dry powder formulations contained MPL and chitosan (ChiSys). Significant anti-rPA titers and anthrax lethal toxin neutralizing antibody (TNA) levels were seen with both rPA containing vaccines, although rPA-specific IgG and TNA levels were reduced in rabbits immunized with rPA plus conj. Nine weeks after immunization, rabbits were exposed to a mean aerosol challenge dose of 278 LD50 of Ames spores. Groups immunized with rPA or with rPA+conj had significant increases in survivor proportions compared to the negative control group by Logrank test (p=0.0001 and 0.003, respectively), and survival was not statistically different for the rPA and rPA+conj immunized groups (p=0.63)," wrote S.D. Klas and colleagues, LigoCyte Pharmaceuticals Inc.
The researchers concluded: "These data demonstrate that a single immunization with our dry powder anthrax vaccine can protect against a lethal aerosol spore challenge 9 weeks later."
Klas and colleagues published their study in Vaccine (A single immunization with a dry powder anthrax vaccine protects rabbits against lethal aerosol challenge. Vaccine, 2008;26(43):5494-502).
For additional information, contact S.D. Klas, LigoCyte Pharmaceuticals, Inc., 2155 Analysis Drive, Bozeman, MT 59718, United States.
The publisher of the journal Vaccine can be contacted at: Elsevier Science Ltd., the Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, Oxon, England.
