Ocular Penetration and Biodistribution of Ac8, a Fully Human Igg Fab Fragment Neutralizing Hsv1 and Hsv2, After Topical Instillation on the Rat Eye

Abstract

Purpose: : To study the potential ocular penetration and biodistribution of AC8, a fully human IgG Fab fragment (53KD) neutralizing HSV1 and HSV2, after topical instillation on the rat eye.

Methods: : AC8 (50µl; 10 or 100µg/ml) was instilled on either intact or de-epithelialized rat cornea, 5 times a day. Control groups received the instillation of PBS (vehicle) and one group of rats received the sub conjunctival injection (50µl) of AC8 as a positive control. At one hour, 6 and 24 hours after AC8 administration, eyes (n=2) were processed for immunohistochemistry on cryosections or (n=4) for AC8 dosage in the ocular media, the cornea and the retina using Elisa assay.

Results: : After topical instillation, AC8 penetrates into the intact eye and can be detected using both immunohistochemistry and Elisa testing at one hour after instillation, in the aqueous humour and in the vitreous. After de-epithelialization of the cornea, the ocular penetration is enhanced in the aqueous humor and in the vitreous. AC8 can be visualized in corneal cells of intact corneas and seems to penetrate in the eyes mostly through a transcleral route. After sub conjunctival injection, the ocular penetration of AC8 is similar to those obtained after instillation on a de-epithelialized cornea. However, sub conjuntival injection on eyes after corneal de-epithelialization results in a 5 times increase in AC8 ocular penetration. Immunohistochemistry revealed that AC8 seemed to accumulate in dendritic sub epithelial cells, demonstrating its corneal penetration.

Conclusions: : After topical instillation, AC8 was measured at efficient anti viral concentrations in the ocular media. AC8 can penetrate in the intact corneal epithelium and during the re-epithelialization process. AC8 could therefore be used as a specific anti HSV agent during the early phase or the acute phase of herpes keratitis.

Keywords: herpes simplex virus • antiviral drugs • cornea: epithelium