Standardization of Plaque Reduction Neutralization Test on 96-well Plates (micro-PRNT) for Zika Virus

Introduction: Plaque Reduction Neutralization Test (PRNT) is considered the “gold standard” by the World Health Organization for the confirmatory diagnosis of Flavivirus infection from the determination of neutralizing antibodies. Zika virus (ZIKV), a Flavivirus widely circulating in Brazil has caused considerable epidemic impact. Although 80% of cases are asymptomatic, virus infection in symptomatic cases causes headache, low fever, mild joint pain, red spots on the skin, itching and redness in the eyes. Other less common symptoms are swelling in the body, sore throat, coughing and vomiting. Infection by ZIKV has great importance especially for pregnant women, since the virus is a potential cause for the birth of children with a congenital malformation, in which the brain does not develop properly, called microcephaly. The Virological Technology Laboratory (LATEV, Bio-Manguinhos/Fiocruz) performs PRNT assays for different Flavivirus species, not only as confirmatory differential diagnosis, but mainly in the evaluation of the immunogenicity of commercial vaccines in development. Bio-Manguinhos currently participates in the development of three different vaccine proposals for the Zika virus. Therefore, considering potential increase in the demand for neutralizing antibody titers for diagnostic and vaccine evaluation, the standardization of a neutralization test for the Zika virus with high sample processing capacity meets the needs of LATEV and, consequently, of Institution and public health.