Human-isolated monoclonal antibody shows promise for protective Zika treatment

Written by Courtney Johnson

Researchers at Vanderbilt University (MO, USA) and Washington University School of Medicine (MO, USA) have isolated a monoclonal antibody, known as ZIK-117, which has exhibited a demonstrable effect on reducing infection of the Zika virus in mouse models. The findings were published recently in Nature.
Zika is a mosquito-borne virus that has surfaced as a global public health risk. Infants born to women infected by the Zika virus have been observed to develop congenital brain abnormalities, such as microcephaly as well as Guillain-Barré syndrome, a neurological disorder affecting the peripheral nervous system that can cause paralysis and even death.

A major outbreak of the Zika virus was reported in Brazil in 2015. To date, transmissions of the virus by mosquitoes have been reported throughout Africa, Asia, the Pacific, and the Americas.

In the current early-stage study, researchers utilized a previously developed high-efficiency method for isolating human monoclonal antibodies, in this case isolating them from the blood of humans previously infected with Zika. The antibodies demonstrated a reaction to the ‘E’ envelope protein on the virus surface.

Subsequent to the isolation of a range of monoclonal antibodies, further cell cultures highlighted the ZIK-117 antibody as an effective broad neutralizer against multiple strains of the virus.

Findings indicated that for mice infected with the Zika virus, injection with ZIK-117 resulted in reduced disease mortality as well as reduced transmission of the virus from mother to fetus.

“These naturally occurring human antibodies isolated from humans represent the first medical intervention that prevents Zika infection and damage to fetuses,” commented James Crowe Jr, director of the Vanderbilt Vaccine Center (MO, USA).

“We’re excited because the data suggests we may have antibody treatments in hand that could be developed for use in pregnant women,” Crowe continued.

“The remarkable potency and breadth of inhibition by ZIKV-117 has great promise,” observed Michael S Diamond (Washington University), “as it was able to inhibit infection by strains from both Africa and America in cell culture and in animals, including during pregnancy.”

Researchers have determined that further studies are required in primates; however, if results are promising for such studies, ZIK-117 may be developed as a protective antibody for pregnant women infected by the Zika virus. They further hope to use this antibody to aid the development of an anti-Zika vaccine in the future.

Sources: Sapparapu G, Fernandez E, Kose N et al. Neutralizing human antibodies prevent Zika virus replication and fetal disease in mice. Nature doi:10.1038/nature20564 (2016) (Epub ahead of print);