Glycoprotein-Specific Antibodies Produced by DNA Vaccination Protect Guinea Pigs from Lethal Argentine and Venezuelan Hemorrhagic Fever

Abstract

Several members of the Arenaviridae can cause acute febrile diseases in humans, often resulting in lethality. The use of convalescent-phase human plasma is an effective treatment in humans infected with arenaviruses, particularly species found in South America. Despite this, little work has focused on developing potent and defined immunotherapeutics against arenaviruses. In the present study, we produced arenavirus neutralizing antibodies by DNA vaccination of rabbits with plasmids encoding the full-length glycoprotein precursors of Junín virus (JUNV), Machupo virus (MACV), and Guanarito virus (GTOV). Geometric mean neutralizing antibody titers, as measured by the 50% plaque reduction neutralization test (PRNT 50 ), exceeded 5,000 against homologous viruses. Antisera against each targeted virus exhibited limited cross-species binding and, to a lesser extent, cross-neutralization. Anti-JUNV glycoprotein rabbit antiserum protected Hartley guinea pigs from lethal intraperitoneal infection with JUNV strain Romero when the antiserum was administered 2 days after challenge and provided some protection (ϳ30%) when administered 4 days after challenge. Treatment starting on day 6 did not protect animals. We further formulated an IgG antibody cocktail by combining anti-JUNV, -MACV, and -GTOV antibodies produced in DNA-vaccinated rabbits. This cocktail protected 100% of guinea pigs against JUNV and GTOV lethal disease. We then expanded on this cocktail approach by simultaneously vaccinating rabbits with a combination of plasmids encoding glycoproteins from JUNV, MACV, GTOV, and Sabia virus (SABV). Sera collected from rabbits vaccinated with the combination vaccine neutralized all four targets. These findings support the concept of using a DNA vaccine approach to generate a potent pan-arenavirus immunotherapeutic. IMPORTANCEArenaviruses are an important family of emerging viruses. In infected humans, convalescent-phase plasma containing neutralizing antibodies can mitigate the severity of disease caused by arenaviruses, particularly species found in South America. Because of variations in potency of the human-derived product, limited availability, and safety concerns, this treatment option has essentially been abandoned. Accordingly, despite this approach being an effective postinfection treatment option, research on novel approaches to produce potent polyclonal antibody-based therapies have been deficient. Here we show that DNA-based vaccine technology can be used to make potently neutralizing antibodies in rabbits that exclusively target the glycoproteins of several human-pathogenic arenaviruses found in South America, including JUNV, MACV, GTOV, and SABV. These antibodies protected guinea pigs from lethal disease when given post-virus challenge. We also generated a purified antibody cocktail with antibodies targeting three arenaviruses and demonstrated protective efficacy against all three targets. Our findings demonstrate that use of the DNA vaccine technology could be used to produce candidate antiarenavirus ne...

Development of horse neutralizing immunoglobulin and immunoglobulin fragments against Junín virus

“…In contrast to mAbs, polyclonal antibodies that were reported to neutralize JUNV, MACV, GTOV, and SBAV were achieved by vaccination of rabbits with mixed plasmids encoding GPCs of the four NW arenaviruses (Golden et al, 2016). In our study, both antisera and JUNV GP1-specific IgG purified from antisera had some cross-neutralizing effect on the five NW clade B arenaviruses, although the results were only validated with VSV pseudotypes bearing arenaviral GPs, which may be different from those validated with actual viruses.…”

“…In addition to mAbs, polyclonal antibodies also play a role in combating JUNV infection. Polyclonal antibodies purified from DNA-immunized rabbits have been demonstrated to protect guinea pigs from a lethal JUNV challenge (Golden et al, 2016). In fact, horse antiserumderived polyclonal antibodies that demonstrated good efficacy against infectious diseases caused by highly pathogenic agents, such as Ebola virus (Wang et al, 2018a;Zheng et al, 2016), West Nile virus (Cui et al, 2016), H5N1 influenza virus (Lu et al, 2006), severe acute respiratory syndrome virus (Lu et al, 2005), and Middle East respiratory syndrome coronavirus (Zhao et al, 2017), have been extensively reported.…”

Keeping track of hidden dangers - The short history of the Sabiá virus

“…However, his hypothesis needs to be confirmed. Recently, Golden et al 19 described a DNA vaccine that could be used as a pan-arenavirus immunotherapeutic.…”

Native functionality and therapeutic targeting of arenaviral glycoproteins

“…An example of promising antibody therapy is a glycoprotein-specific IgG cocktail, produced by DNA vaccination, that has been demonstrated to protect experimental animals against lethal JUNV and GTOV challenge. Encouragingly, some, albeit limited, cross-neutralization was observed between the JUNV and MACV glycoprotein-specific sera [46]. …”

“…The successful development of a JUNV vaccine has stimulated considerable interest in the development of vaccines to other arenaviruses and potentially cross-protective vaccines [46,48–51]. …”