Improved Anthrax Vaccine on the Anvil

by Rajashri on Sep 7 2009 8:28 PM

Two small protein fragments that could lead to improved anthrax vaccine with less side effects have been discovered by scientists from Albert Einstein College of Medicine of Yeshiva University.

The current anthrax vaccine is intended mainly for members of the armed forces serving in areas considered high risk and for individuals involved in homeland biosecurity.

"Our research was motivated by the fact that the current anthrax vaccine has significant limitations and there is great need for a better one," said lead author Nareen Abboud, an Einstein postdoctoral fellow and lead author of the study.

Anthrax results in part from toxic proteins, or toxins, that the multiplying bacteria secrete. The current anthrax vaccine employs one of these proteins, which elicits protective antibodies when injected into people.

While this 40-year-old vaccine can prevent disease, it has significant drawbacks. Immunity is temporary, and five injections over the course of 18 months are needed to sustain it.

One in five vaccine recipients develop redness, swelling or pain at the injection site, and a small number develop severe allergic reactions.

During the study, scientists focused on the protein toxin used in the current vaccine, looking for the smallest protein sections (known as peptides) that could trigger the production of protective antibodies when injected into animals.

They injected the current vaccine into mice and recovered six different "pure" strains of antibodies known as monoclonal antibodies.

They then mixed each type of antibody with the 145 peptides formed by chopping up the vaccine protein.

Ultimately, the researchers found that two of the 145 peptides fit the bill: Each peptide elicited antibodies when injected into mice, and these antibodies protected macrophages from death that would normally have occurred when the macrophages were exposed to anthrax toxin.

The next step in the Einstein research will be to inject the peptides into an animal model to see if the peptides can protect against anthrax infection.

"We're hopeful that the two peptides that we have identified in this study can offer these benefits," said Abboud.

The study appears in The Journal of Biological Chemistry.