Scientists, including one of Indian origin, have identified a human antibody that may reduce Zika infection, paving way for a vaccine against the virus which is believed to cause serious birth defects in babies. The antibody, called ZIKV-117, markedly reduced infection by the Zika in a mouse model and also protected the foetus in pregnant mice infected with the virus. Zika is believed to cause microcephaly, unusually small heads, and other congenital malformations in children born to infected women. Similar protection studies in primates are warranted, and if the findings hold up, ZIKV-177 could be developed as a protective antibody treatment for pregnant women at risk of Zika infection, the researchers concluded. The findings may also aid efforts to develop an effective anti-Zika vaccine, said James Crowe Jr, from the Vanderbilt University Medical Centre in the US.
“These naturally occurring human antibodies isolated from humans represent the first medical intervention that prevents Zika infection and damage to foetuses,” said Crowe. “We’re excited because the data suggests we may have antibody treatments in hand that could be developed for use in pregnant women,” he said. “The remarkable potency and breadth of inhibition by ZIKV-117 has great promise, as it was able to inhibit infection by strains from both Africa and America in cell culture and in animals, including during pregnancy,” said Michael S Diamond from Washington University. Zika is a mosquito-borne virus that has emerged as a global public health threat. In addition to its association with congenital birth defects, Zika has been linked to Guillain-Barre syndrome, a neurological disorder that can lead to paralysis and death.
Since a major outbreak was reported in Brazil last year, Zika infections transmitted by mosquitoes have been reported throughout Africa, Asia, the Pacific, and the Americas. Monoclonal antibodies are made from a single clone of B cells, a type of white blood cell, that have been fused to myeloma (cancer) cells to form fast-growing “hybridomas.” This allows researchers to quickly generate large quantities of antibodies against specific viral targets. For the study, researchers including Gopal Sapparapu isolated antibodies from the blood of people who had been previously infected with the Zika virus in different parts of the world. The antibodies reacted to the envelope or “E” protein on the surface of the virus. The researchers then generated a variety of monoclonal antibodies. In cell culture studies, they identified one, ZIKV-117, which broadly neutralised several different strains
of the virus.
In mice infected by the Zika virus, injection of the antibody markedly reduced disease and mortality, and reduced transmission from mother to foetus. The study was published in the journal Nature.