A new technique creates all-purpose antibodies that can be activated at a moment's notice.
Immunity on demand. I'm Bob Hirshon and this is Science Update.
Vaccines can take weeks or months to generate the antibodies that eventually protect you. But Scripps Research Institute biologist Carlos Barbas and his colleagues have proposed a shortcut. First, give a conventional vaccine—one that gives you an ongoing supply of generic antibodies. Then, whenever you're exposed to a new threat, add designer molecules that instantly stick to those antibodies and direct them toward chosen targets.
So you'd be producing new antibodies that were waiting to be programmed, at the same time your programmed antibodies were going after their target.
Barbas' team has proved the concept in mice, making them immediately resistant to cancer. He imagines that humans might someday take customized pills that deliver instant immunity, to anything from the flu to a bioterror attack. I'm Bob Hirshon for AAAS, the Science Society.
Making Sense of the Research
Immunization (also called vaccination) is a great public health success story. Today, diseases that once routinely killed or permanently disabled people, like measles, polio, and diphtheria, are now nearly unheard of in industrialized countries. Immunizations even led to the total extinction of deadly smallpox.
Most of the time, immunizations aren't working against a ticking clock. You get immunized as a baby or young child, and the antibodies you develop protect for the rest of your life. However, it takes at least a week or two for the body to mount a full immune response to the vaccine. In some cases, it takes several vaccinations over a period of months or years to create a permanent effect. If you were exposed to the actual germs during this window of time, you could still develop the disease. This rarely happens with childhood immunizations, since decades of immunizations have made these disease-causing germs scarce.
However, there are other cases in which an instant vaccine would come in handy: against a rare pandemic like swine flu, for example, or a bioterror attack that uses a never-before-seen mutant virus. Rather than try to force the body to make antibodies much faster than usual—a very challenging, perhaps impossible task—Barbas and his colleagues decided on a different strategy. Using a chemical drug, they triggered an immune response in mice that created generic antibodies with a special property: a spot where they tend to bind to a sticky molecule, called a “linker.” These linker molecules can be manufactured in a lab, and outfitted with additional molecules that recognize and stick to disease-causing targets, like cancer cells. When they injected the mice with cancer-seeking linker molecules, the generic antibodies grabbed them up, and transformed instantly into anti-cancer antibodies.
If this were to work in humans, then whenever you needed protection against an immediate threat, you could get a similar injection, or even swallow a pill, that would give you temporary immunity. (After a while, the targeted antibodies would clear from your system, and your body would make new, generic antibodies that could be used against something else.) It's a long way off, but it's a tantalizing idea—one that could give people the potential to fight off any illness, without having to get thousands of vaccinations “just in case.”
Now try and answer these questions:
- What is instant immunity?
- How would this differ from today's vaccinations?
- How does Barbas' system work?
- Would there be limitations to this new form of immunity? If so, what are they?
You may want to check out the March 20, 2009 Science Update Podcast to hear further information about this Science Update and the other programs for that week. This podcast's topics include: new vaccines provide instant immunity, addiction and Parkinson's disease, the upside of salt, ship pollution threatens coastal residents, and more.
The History of Vaccines, from the National Museum of American History, traces the development of vaccines from the earliest efforts to the modern era, and describes how they work.
The Immune System: Friend and Foe, from the Howard Hughes Medical Institute, features an interactive presentation about the human immune system. In four lectures, two noted scientists who have advanced our understanding of the immune system explore its secrets.