Adenovirus Vectors Expressing Hantavirus Proteins Protect Hamsters against Lethal Challenge with Andes Virus

Abstract

Hantaviruses infect humans following aerosolization from rodent feces and urine, producing hemorrhagic fever with renal syndrome and hantavirus pulmonary syndrome. Due to the high rates of mortality and lack of therapies, vaccines are urgently needed. Nonreplicating adenovirus (Ad) vectors that express Andes hantavirus (ANDV) nucleocapsid protein (AdN) or glycoproteins (AdG N and AdG C ) were constructed. Ad vectors were tested for their ability to protect Syrian hamsters from a lethal ANDV infection that mimics the pulmonary disease seen in humans. When administered once, all three Ad vectors, individually or in combination, elicited a robust immune response that protected hamsters. No vaccinated animal died, and there were no obvious clinical signs of disease. Further, hantavirus RNA was not detected by sensitive reverse transcription-PCR in tissues and blood of hamsters immunized with both AdG N and AdG C . Cellular immunity appeared to be important for protection because the AdN vector completely protected animals. All three Ad vectors produced strong cytotoxic T-lymphocyte responses directed to hantavirus proteins in mice. Moreover, hamsters vaccinated with AdN, AdG N , or AdG C produced no detectable neutralizing antibodies yet were protected. These Ad vectors represent the first vaccines that prevent lethal hantavirus disease and, in some instances (AdG N and AdG C ), provide sterile immunity. These observations set the stage for a more detailed characterization of the types of immunity required to protect humans from hantavirus infections.Hantaviruses (genus Hantavirus, family Bunyaviridae) are a closely related group of rodent-borne viruses that are associated with two human diseases involving vascular leakage: hemorrhagic fever with renal syndrome (HFRS) and hantavirus pulmonary syndrome (HPS). Humans frequently acquire hantaviruses through inhalation of aerosolized infectious material shed by rodents in urine, feces, or saliva (reviewed in references 6, 24, and 38) Throughout Asia and Europe, over 200,000 cases of HFRS requiring hospitalization are documented annually, with lethality rates ranging from 0.1% to 15% (reviewed in references 32 and 45). HPS occurs throughout the Americas and although cases occur less frequently, lethality rates can range as high as 30 to 50% (reviewed in references 22, 24, and 32). Sin Nombre virus (SNV) and Andes virus (ANDV) cause the most frequently recognized and severe cases of human disease in North and South America, respectively (11, 38). SNV, carried primarily by Peromyscus maniculatus (deer mice), was discovered in 1993 in the southwestern United States during an outbreak of acute respiratory distress syndrome (8,12). ANDV, carried primarily by Oligoryzomys longicaudatus (pygmy rice rat), was identified in 1995 as the agent causing a series of HPS outbreaks in Argentina and Chile (27,28). With ANDV there is evidence for personto-person transmission (reviewed in reference 11).Clinically, HPS is characterized by a febrile, cardiopulmonary, diuretic, and convalesce...

Human pathogenic hantaviruses and prevention of infection

“…In a hamster model, recombinant adenovirus expressing ANDV N, Gn or Gc protein protects the animals against lethal challenge with this hantavirus. 63 Induction of neutralizing antibodies and protection against SEOV challenge were also observed after immunization with replication-competent recombinant canine adenovirus expressing SEOV Gn or Gc.…”

“…It has been shown in the HCPS animal model that vaccination with adenoviral vectors expressing any of the individual hantaviral structural proteins (N protein, Gn or Gc) protects Syrian hamsters from lethal challenge. 63 Strikingly, in this study protective immunity was established in the absence of detectable neutralizing…”

Vesicular Stomatitis Virus-Based Vaccine Protects Hamsters against Lethal Challenge with Andes Virus

“…First, passive immune transfer with serum derived from DNA-vaccinated nonhuman primates or rabbits using a vector expressing the ANDV glycoprotein precursor (GPC) protected hamsters against lethal ANDV challenge (10, 24); however, direct immunization of the hamsters with the DNA vaccine did not afford protection. Second, recombinant human adenovirus 5 (Ad5)-based vaccines expressing either an ANDV glycoprotein (G N or G C ) or the nucleocapsid (N) protein protected hamsters from lethal ANDV infection following a single immunization (60). In this study, BALB/c mice immunized with the Ad vectors developed a fairly robust CD8 ϩ cytotoxic lymphocyte response, although CD8 ϩ responses in hamsters were not monitored, due to a lack of available reagents.…”

“…After 28 days, the hamsters were challenged with ANDV at 100ϫ LD 50 (the dose leading to death in 50% of the animals) by i.p. injection as described previously (60). For time-to-protection and postexposure studies, different groups of animals were immunized with 10 5 PFU of VSV⌬G/ANDVGPC (study group; 10 animals per group), VSV⌬G/ZEBOVGP, or DMEM (control groups; 6 and 3 animals per group, respectively) at 14, 7, and 3 days prechallenge or at 24 and 72 h postchallenge.…”

“…The hantavirus species ANDV, strain Chile 9717869 (44) (kindly provided by C. Schmaljohn, U.S Army Medical Research Institute of Infectious Diseases, Fort Detrick, Frederick, MD), was propagated in Vero E6 cells containing 2% FBS. The titer of ANDV was determined as described previously (60). VSV containing the Zaire ebolavirus (strain Mayinga-76) glycoprotein (VSV⌬G/ZEBOVGP) (15,28) or wild-type VSV containing the VSV G glycoprotein (VSV wt) were used as control viruses in experiments where indicated.…”