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Protective effect of different anti-rabies virus VHH constructs against rabies disease in mice.

Terryn S, Francart A, Lamoral S, Hultberg A, Rommelaere H, Wittelsberger A, Callewaert F, Stohr T, Meerschaert K, Ottevaere I, Stortelers C, Vanlandschoot P, Kalai M, Van Gucht S - PLoS ONE (2014)

Bottom Line: The effect of systemic treatment was significantly improved by increasing the half-life of Rab-E8/H7 through linkage with a third VHH targeted against albumin.Overall, the therapeutic benefit seemed well correlated with the time of brain exposure and the plasma half-life of the used VHH construct.These results, together with the ease-of-production and superior thermal stability, render anti-rabies VHH into valuable candidates for development of alternative post exposure treatment drugs against rabies.

View Article: PubMed Central - PubMed

Affiliation: National Reference Centre of Rabies, Viral Diseases, Scientific Institute of Public Health (WIV-ISP), Brussels, Belgium; Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.

ABSTRACT
Rabies virus causes lethal brain infection in about 61000 people per year. Each year, tens of thousands of people receive anti-rabies prophylaxis with plasma-derived immunoglobulins and vaccine soon after exposure. Anti-rabies immunoglobulins are however expensive and have limited availability. VHH are the smallest antigen-binding functional fragments of camelid heavy chain antibodies, also called Nanobodies. The therapeutic potential of anti-rabies VHH was examined in a mouse model using intranasal challenge with a lethal dose of rabies virus. Anti-rabies VHH were administered directly into the brain or systemically, by intraperitoneal injection, 24 hours after virus challenge. Anti-rabies VHH were able to significantly prolong survival or even completely rescue mice from disease. The therapeutic effect depended on the dose, affinity and brain and plasma half-life of the VHH construct. Increasing the affinity by combining two VHH with a glycine-serine linker into bivalent or biparatopic constructs, increased the neutralizing potency to the picomolar range. Upon direct intracerebral administration, a dose as low as 33 µg of the biparatopic Rab-E8/H7 was still able to establish an anti-rabies effect. The effect of systemic treatment was significantly improved by increasing the half-life of Rab-E8/H7 through linkage with a third VHH targeted against albumin. Intraperitoneal treatment with 1.5 mg (2505 IU, 1 ml) of anti-albumin Rab-E8/H7 prolonged the median survival time from 9 to 15 days and completely rescued 43% of mice. For comparison, intraperitoneal treatment with the highest available dose of human anti-rabies immunoglobulins (65 mg, 111 IU, 1 ml) only prolonged survival by 2 days, without rescue. Overall, the therapeutic benefit seemed well correlated with the time of brain exposure and the plasma half-life of the used VHH construct. These results, together with the ease-of-production and superior thermal stability, render anti-rabies VHH into valuable candidates for development of alternative post exposure treatment drugs against rabies.

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Related in: MedlinePlus

Virus spread in the mouse brain following intranasal rabies virus inoculation.The graph presents the profile of viral RNA in different parts of the brain (indicated in the left photo) upon intranasal inoculation of 102.5 CCID50/mouse. Groups of mice (n = 7–10) were intranasally inoculated with rabies virus and sacrificed at various time points post inoculation (DPI). Viral loads were determined by qRT-PCR.
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pone-0109367-g001: Virus spread in the mouse brain following intranasal rabies virus inoculation.The graph presents the profile of viral RNA in different parts of the brain (indicated in the left photo) upon intranasal inoculation of 102.5 CCID50/mouse. Groups of mice (n = 7–10) were intranasally inoculated with rabies virus and sacrificed at various time points post inoculation (DPI). Viral loads were determined by qRT-PCR.

Mentions: Virus spread through the brain over time was monitored by measuring the change in viral RNA load in the brain by quantitative real-time PCR (qRT-PCR) from 1 to 7 DPI, at which time clinical disease becomes obvious (Figure 1). Already at 1 DPI, virus can be detected in the olfactory bulbs (of 3/10 mice), with all mice being positive from 2 DPI onwards. The virus spreads from the frontal to the distal parts of the brain in a matter of days. In the cerebrum and diencephalon, viral RNA can be detected as soon as 2 DPI (in 4/7 mice) and from 3 DPI onwards in all mice. In the hindbrain and cerebellum, RNA can be detected as soon as 3 DPI (in 2/7 mice) and in all mice from 4 DPI onwards. Peak viral RNA levels (ΔCt≥25) are observed from 6 DPI onwards, which precedes the occurrence of severe neurological disease (score≥6) by 1 day. In conclusion, the intranasal inoculation of rabies virus provides an excellent infection model to study the efficacy of antiviral treatment in the brain. In contrast to intracerebral inoculation, it leaves the brain mechanically intact, and yields a highly reproducible brain infection and disease outcome with little variation in the median survival time.


Protective effect of different anti-rabies virus VHH constructs against rabies disease in mice.

Terryn S, Francart A, Lamoral S, Hultberg A, Rommelaere H, Wittelsberger A, Callewaert F, Stohr T, Meerschaert K, Ottevaere I, Stortelers C, Vanlandschoot P, Kalai M, Van Gucht S - PLoS ONE (2014)

Virus spread in the mouse brain following intranasal rabies virus inoculation.The graph presents the profile of viral RNA in different parts of the brain (indicated in the left photo) upon intranasal inoculation of 102.5 CCID50/mouse. Groups of mice (n = 7–10) were intranasally inoculated with rabies virus and sacrificed at various time points post inoculation (DPI). Viral loads were determined by qRT-PCR.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4210127&req=5

pone-0109367-g001: Virus spread in the mouse brain following intranasal rabies virus inoculation.The graph presents the profile of viral RNA in different parts of the brain (indicated in the left photo) upon intranasal inoculation of 102.5 CCID50/mouse. Groups of mice (n = 7–10) were intranasally inoculated with rabies virus and sacrificed at various time points post inoculation (DPI). Viral loads were determined by qRT-PCR.
Mentions: Virus spread through the brain over time was monitored by measuring the change in viral RNA load in the brain by quantitative real-time PCR (qRT-PCR) from 1 to 7 DPI, at which time clinical disease becomes obvious (Figure 1). Already at 1 DPI, virus can be detected in the olfactory bulbs (of 3/10 mice), with all mice being positive from 2 DPI onwards. The virus spreads from the frontal to the distal parts of the brain in a matter of days. In the cerebrum and diencephalon, viral RNA can be detected as soon as 2 DPI (in 4/7 mice) and from 3 DPI onwards in all mice. In the hindbrain and cerebellum, RNA can be detected as soon as 3 DPI (in 2/7 mice) and in all mice from 4 DPI onwards. Peak viral RNA levels (ΔCt≥25) are observed from 6 DPI onwards, which precedes the occurrence of severe neurological disease (score≥6) by 1 day. In conclusion, the intranasal inoculation of rabies virus provides an excellent infection model to study the efficacy of antiviral treatment in the brain. In contrast to intracerebral inoculation, it leaves the brain mechanically intact, and yields a highly reproducible brain infection and disease outcome with little variation in the median survival time.

Bottom Line: The effect of systemic treatment was significantly improved by increasing the half-life of Rab-E8/H7 through linkage with a third VHH targeted against albumin.Overall, the therapeutic benefit seemed well correlated with the time of brain exposure and the plasma half-life of the used VHH construct.These results, together with the ease-of-production and superior thermal stability, render anti-rabies VHH into valuable candidates for development of alternative post exposure treatment drugs against rabies.

View Article: PubMed Central - PubMed

Affiliation: National Reference Centre of Rabies, Viral Diseases, Scientific Institute of Public Health (WIV-ISP), Brussels, Belgium; Laboratory of Virology, Department of Virology, Parasitology and Immunology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.

ABSTRACT
Rabies virus causes lethal brain infection in about 61000 people per year. Each year, tens of thousands of people receive anti-rabies prophylaxis with plasma-derived immunoglobulins and vaccine soon after exposure. Anti-rabies immunoglobulins are however expensive and have limited availability. VHH are the smallest antigen-binding functional fragments of camelid heavy chain antibodies, also called Nanobodies. The therapeutic potential of anti-rabies VHH was examined in a mouse model using intranasal challenge with a lethal dose of rabies virus. Anti-rabies VHH were administered directly into the brain or systemically, by intraperitoneal injection, 24 hours after virus challenge. Anti-rabies VHH were able to significantly prolong survival or even completely rescue mice from disease. The therapeutic effect depended on the dose, affinity and brain and plasma half-life of the VHH construct. Increasing the affinity by combining two VHH with a glycine-serine linker into bivalent or biparatopic constructs, increased the neutralizing potency to the picomolar range. Upon direct intracerebral administration, a dose as low as 33 µg of the biparatopic Rab-E8/H7 was still able to establish an anti-rabies effect. The effect of systemic treatment was significantly improved by increasing the half-life of Rab-E8/H7 through linkage with a third VHH targeted against albumin. Intraperitoneal treatment with 1.5 mg (2505 IU, 1 ml) of anti-albumin Rab-E8/H7 prolonged the median survival time from 9 to 15 days and completely rescued 43% of mice. For comparison, intraperitoneal treatment with the highest available dose of human anti-rabies immunoglobulins (65 mg, 111 IU, 1 ml) only prolonged survival by 2 days, without rescue. Overall, the therapeutic benefit seemed well correlated with the time of brain exposure and the plasma half-life of the used VHH construct. These results, together with the ease-of-production and superior thermal stability, render anti-rabies VHH into valuable candidates for development of alternative post exposure treatment drugs against rabies.

Show MeSH
Related in: MedlinePlus