UC San Diego News Center


Molecular Homing Beacon Redirects Human Antibodies to Fight Pathogenic Bacteria

Bacteria-specific molecules attract pre-existing antibodies to help immune system clear infection



The molecular homing beacon is the brainchild of study co-author and Nobel Laureate Kary Mullis, PhD, who invented polymerase chain reaction (PCR), a now-common lab technique used to replicate DNA.

One end of the homing beacon is made up of a DNA aptamer, a small piece of DNA that can be selected from a pool of billions of candidates based on its ability to bind tightly to a particular target. In this test case, the aptamer specifically targeted group A Streptococcus, the bacteria that causes strep throat and invasive skin infections, while leaving human cells untouched. The other end of the homing beacon is alpha-Gal, a type of sugar molecule. Humans naturally produce antibodies against alpha-Gal. That’s because alpha-Gal is foreign to humans. Other mammals and some microbes produce it. Humans have evolved antibodies against it when we eat meat or are exposed to alpha-Gal-generating microbes in our environment.





“We’re picturing a future in which doctors have a case full of pathogen-specific Alphamers at their disposal,” Nizet said. “They see an infected patient, identify the causative bacteria and pull out the appropriate Alphamer to instantly enlist the support of the immune system in curing the infection.”

An animation of the Alphamer technology is available at:

Co-authors of this study include John H. Hwang, and Emma Leire, UC San Diego; Bradley Hall, and Kary B. Mullis, Altermune Technologies; John Iacomini, Tufts University School of Medicine; Robert Old, Loxbridge Research; Uri Galili, University of Massachusetts Medical School; Charles Roberts, and Mike Westby, Altermune Technologies and Loxbridge Research.

This research was funded by Altermune Technologies, LLC (Irvine, CA).

Disclosure: Victor Nizet is a member of the Scientific Advisory Board for Altermune Technologies, LLC.