Development of a Rapid Diagnostic Test Kit to Detect IgG/IgM Antibody against Zika Virus Using Monoclonal Antibodies to the Envelope and Non-structural Protein 1 of the Virus

Kim, Yeong Hoon; Lee, Jihoo; Kim, Young-Eun; Chong, Chom-Kyu; Pinchemel, Yanaihara; Reisdörfer, Francis; Coelho, Joyce Brito; Dias, Ronaldo Ferreira; Bae, Pan Kee; Gusmão, Zuinara Pereira Maia; Ahn, Hye-Jin; Nam, Ho-Woo

In the present study, we successfully applied gold conjugate for the development of a rapid diagnostic testing (RDT) system with the monoclonal antibodies J5E1 and J2G7 that correspond to the envelope (E) and non-structural 1 (NS1) proteins of ZIKV, respectively. Serological diagnosis of ZIKV is far from easy because of extensive cross-reactivity between antibodies against other flaviviruses [35] . With the baculovirus expression system, we can obtain soluble expressed and highly purified recombinant E & NS1 proteins of ZIKV, and the resultant sensitivity and specificity of Zika RDT were excellent. Zika RDT showed 100% identical results with the standard panel using ELISA and PRNT. Zika RDT requires neither electricity nor any specific laboratory equipment. It is stable at 4-30ËšC and has a long shelf life. It is simple to use so the assay is fast, and avoids blood being drawn from suspicious patients. These characteristics make it useful in a field setting. However, some cross-reaction with the DENV (16.7% and 5.6% for IgG and IgM, respectively) was observed. Fortunately, there was no cross-reaction with anti-West Nile virus, anti-yellow fever virus, anti-HCV serums. While the flavivirus NS1) is secreted by infected cells and is involved in immune evasion and pathogenesis [36] . Distinct features that may be related to the ZIKV neurotropism of the E protein [37, 38] and different electrostatic characteristics of the NS1 protein [39] would result in the high efficacy of our RDT and its differentiating of other flavivirus infections.