Antibody-dependent enhancement and the challenge for a Zika vaccine

Antibody-dependent enhancement and the challenge for a Zika vaccine

'Antibodies are made to attach to certain proteins on the surface of an invading organism, called antigens. By sticking to these antigens, antibodies block the invader’s ability to replicate, and enter cells, thereby rendering the invader useless.

Then the janitor cells of the immune system (macrophages, literally “big eaters”), search around for these “useless invaders” attached to antibodies, engulf them and chop them up for re-use or excretion.

However, some viruses actually get inside macrophages, using the antibodies as a Trojan horse. They pretend to be useless, getting engulfed by the macrophage and then converting the macrophage into a virus-producing machine. This is antibody-dependent enhancement.


Zika virus is a flavivirus, similar to dengue. In fact, for people infected with the virus, infection is indistinguishable from dengue using classic antibody tests. This made scientists wonder: could prior infection with Zika cause an antibody-dependent enhancement response following dengue infection or vice versa?'

Emily Johnston Flies, PhD student in Disease Ecology, University of South Australia

and Cameron Webb, Clinical Lecturer and Principal Hospital Scientist, University of Sydney explain:


Photo: Proteas - a stunning South African native that grows well here.

1 Reply

  • Fascinating photo Neil!

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