Cross Neutralizing Dengue Antibodies

Dengue virus threatens many areas, yet no broadly effective therapeutics or vaccines exist. Dengue fever typically only causes mild symptoms, but occasionally will develop into the potentially lethal dengue hemorrhagic fever1. Dengue hemorrhagic fever is strongly associated with a secondary infection of a different dengue serotype2. The severe symptoms may be due to antibody-dependent enhancement (ADE). ADE occurs when non-neutralizing antibodies against one dengue serotype increase the infectivity of a second dengue serotype2. However, if the infections occur within a year of each other, the expected immunity is achieved. This study seeks to uncover a cross-reactive neutralizing antibody against multiple dengue serotypes. A subject was exposed to dengue one and two within a period of one year. The subject’s B cells were cultured, and RNA was extracted and used to generate cDNA. This underwent two rounds of PCR and sequencing to determine the identity of the antibody. Plasmids were generated by transformation and transfected into cells that expressed the antibodies which were then purified. Purified antibodies were tested for binding ability against all four dengue serotypes. Binding antibodies were tested for neutralization capabilities, and then the capacity for antibody-dependent enhancement. Of the original 28 samples, three unique antibody lineages were determined. Of those, 3B3_1B3 tested positive for binding to all four dengue serotypes. 3B3 is strongly neutralizing against dengue 2 Tonga, and mildly neutralizing against dengue 1 and 4. Dengue 3 neutralization, as well as any capacity for enhancement has yet to be determined. Discovery of a cross-reactive neutralizing antibody is essential in developing a safe vaccine effective against all dengue serotypes. Additionally, finding such an antibody would allow for further study on the process of ADE, and how the time between infections plays a role. [1] Dengue and severe dengue. (2020, June 23). Retrieved December 09, 2020, from https://www.who.int/news-room/fact- sheets/detail/dengue-and- severe-dengue [2] Katzelnick, L. C., Gresh, L., Halloran, M. E., Mercado, J. C., Kuan, G., Gordon, A., Balmaseda, A., and Harris, E. (2017) Antibody- dependent enhancement of severe dengue disease in humans, Science 358, 929