Scientists from the Scripps Research Institute have developed a methodology to begin building vaccines that more effectively prepare antibodies for attacking pathogens. By attaching to antibodies, the new chemical compounds can train them on how to target specific classes of pathogens.
From MIT Tech Review:
Barbas and his team developed a two-stage chemical strategy that first puts the body’s antibodies on alert, and then gives them instructions on which targets to destroy. In the first stage, Barbas designed a chemical that, once injected, enables antibodies to form covalent bonds. Normally, antibodies cannot form such bonds. The second stage involves injecting a small adapter molecule with two parts: one that bonds covalently with antibodies, and the other that binds with a specific epitope, or cancer marker. When injected, this adapter molecule links with antibodies and then seeks out and attaches to a target’s specific epitope. The method is essentially like handing antibodies a beeper and putting them on standby. They wait around for a “call,” in the form of the adapter molecule, which, once connected, instantly leads them directly to a target’s weak spot, where the antibody can attack and deactivate the pathogen.
In their experiments, Barbas and his colleagues implanted tumors for colon cancer and melanoma into the flanks of mice and watched the tumors grow over time. They then injected mice with a chemical that “primed” antibodies, before injecting them again with adapter molecules that bind both with antibodies and with integrins–surface proteins found on each type of tumor. The researchers measured the volume of tumors up to a month after injection, then removed the tumors and weighed them. They found that those treated with the two-stage vaccine were significantly smaller than those removed from animals that had been injected with just the adapter molecules, or with a commonly used adjuvant vaccine. “The molecules we used can also bind human receptors as well,” says Barbas. “This could potentially translate directly into humans.”
More from MIT Technology Review…
Abstract in PNAS…
image: Colour-enhanced electron micrograph of Adenovirus particles. Adenoviruses are DNA-containing viruses that cause cold-like infections of the upper respiratory tract. The virus particles are 70-90 nanometres in diameter. Wellcome Images