A Therapeutic Antiviral Antibody Inhibits the Anterograde Directed Neuron-to-Cell Spread of Herpes Simplex Virus and Protects against Ocular Disease

Abstract

Herpes simplex virus (HSV) is a leading cause of blindness and viral encephalitis in the developed world. Upon reactivation from sensory neurons, HSV returns via axonal transport to peripheral tissues where it causes, e.g., severe, potentially blinding ocular diseases. In the present study we investigated whether the HSV-1/2 glycoprotein B-specific antibody mAb 2c or its humanized counterpart mAb hu2c can protect from ocular disease in a mouse model of HSV-1-induced acute retinal necrosis (ARN). In this model the viral spread from the initially infected to the contralateral eye resembles the routes taken in humans upon HSV reactivation. Systemic antibody treatment prior or early after infection effectively protected the mice from the development of ARN. These observations suggest that the antibody potently neutralized the infection and inhibited the viral transmission, since there was almost no virus detectable in the contralateral eyes and trigeminal ganglia of antibody treated mice. Besides of neutralizing free virus or limiting the infection via activating the complement or cellular effector functions, blocking of the anterograde directed neuron-to-cell spread of HSV represents a viable mode of action how mAb 2c protected the mice from ARN. We proved this hypothesis using a microfluidic chamber system. Neurons and epithelial cells were cultured in two separate compartments where the neurons sent axons via connecting microgrooves to the epithelial cells. Neurons were infected with a reporter HSV-1 strain expressing mCherry, and the co-culture was treated with neutralizing antibodies. In contrast to commercial polyclonal human HSV-neutralizing immunoglobulins, mAb 2c effectively blocked the anterograde directed neuron-to-cell transmission of the virus. Our data suggest that the humanized HSV-1/2-gB antibody protects mice from ocular disease by blocking the neuronal spread of HSV. Therefore, mAb hu2c may become a potent novel therapeutic option for severe ocular HSV infections.

Inner tegument proteins of Herpes Simplex Virus are sufficient for intracellular capsid motility in neurons but not for axonal targeting

“…We have shown previously that such neurons are productively infected, and that they transmit HSV-1 to co-cultured epithelial cells upon infection with the HSV1(17 + )Lox-Che (c.f. Table 1 ), which had been cloned into a bacterial artificial chromosome (BAC), and which expresses mCherry as a reporter [ 52 , 53 ].…”

“…The neurons from the DRG of adult mice formed neurites with axonal features which contained ankyrinG and microtubules of uniform polarity with the plus-ends pointing towards the axon endings. Furthermore, we have shown previously that HSV1(17 + )Lox strains that have been cloned into a bacterial artificial chromosome and therefore lack the Ori L [ 84 , 85 ] infect such neurons and spread the infection to neighboring epithelial cells [ 52 , 53 ]. Hence murine adult DRG neurons provide a versatile system to study productive HSV-1 infection and transport in axons with unipolar microtubules in vivo and in vitro .…”

Distinguishing Features of High- and Low-Dose Vaccine against Ocular HSV-1 Infection Correlates with Recognition of Specific HSV-1–Encoded Proteins

“…One family of recognized proteins included six HSV-1 encoded glycoproteins: gB, glycoprotein H (gH), glycoprotein C (gC), gD, glycoprotein E (gE), and glycoprotein L (gL). Of the two glycoproteins with the highest reactivity score to the antiserum, both recombinant gB and gH or derived peptides used as immunogens or antagonists have been reported to suppress HSV replication, block anterograde or retrograde spread of the virus, and/or prevent virus-associated disease through a robust T cell or Ab response to the Ag (23,29,31,57,58). Recombinant gC and gD have also been evaluated as prototypical vaccines against HSV-1 administered prophylactically or therapeutically with reported success (19-21, 25, 59).…”

Herpes Simplex Virus Type 2 Is More Difficult to Neutralize by Antibodies Than Herpes Simplex Virus Type 1

“…The humanized antibody mAb hu2c shows equal binding affinity as the parental murine antibody mAb 2c [21], which binds both HSV-1 gB and HSV-2 gB, with an equal affinity in a nanomolar range [21,22]. The humanized antibody was further investigated in various animal models, and was highly protective against HSV-1 infections in the NOD/SCID mouse model for immune deficiency [21], and mouse models for ocular HSV-1 infections of the cornea [23] and retina [24,25]. Furthermore, the antibody was shown to neutralize drug resistant clinical HSV-1 and HSV-2 isolates in vitro.…”