Antibody-dependent cellular cytotoxicity mediated by polymorphonuclear leukocytes and mononuclear cells against HSV-1 infected primary cultures of rabbit corneal epithelium

The roles of rabbit polymorphonuclear leukocytes (PMNL) and mononuclear cells (MC) for the regulation of ocular herpes simplex virus-1 (HSV-1) infection were studied. The antibody-dependent cellular cytotoxicity (ADCC) mediated by PMNL and MC from normal rabbit peripheral blood was assessed kinetically employing a specific 51Cr release assay. The HSV-1 infected primary cultures of rabbit corneal epithelium (PRCE) were used as the target cells to obtain a homologous assay system. The PRCE was prepared by an epithelium outgrowth technique and identified by electron microscopy. The expression of the surface HSV-1 antigens on PRCE was examined by indirect immunofluorescent staining; the cell population stained by fluorescein increased from 40% at 3 hr postinfection (PI) to 100% at 8 hr PI. To determine how early the cytotoxicity occurs, PRCE were infected with HSV-1 for 2 hrs. After 2 hrs, the ADCC was checked every 10 min for the first 40 min and then at 1, 2 and 4 hr of incubation. The cytotoxicity was apparent at 10 min postincubation and reached 46% by PMNL and 40% by MC at 4 hr postincubation (6 hr PI). Significant cytotoxic effect (26% by PMNL and 16% by MC) occurred as early as 3 hr PI. When the one-step growth cycle of HSV-1 was studied in the PRCE, HSV-1 had an eclipse period of 4 hr and a rise period of 8 hr. This suggests that rabbit PMNL and MC have the potential to eliminate the HSV-1 infected rabbit corneal epithelium before HSV matures in the cells.

Thymine arabinoside (Ara-T) topical and iontophoretic application for herpes simplex virus type 1 and type 2 skin infections in hairless mice

The antiviral agent thymine arabinoside (9-beta-D-arabinofuranosyl thymine, Ara-T) was applied topically and by anodal (+) iontophoresis in a NaCl solution to Herpes simplex virus type 1 (HSV-1), and Herpes simplex virus type 2 (HSV-2) skin infections in hairless mice. The chemotherapeutic efficacy of Ara-T was evaluated employing the parameters of mean lesion score, number of mice with signs of neurological involvement (paralysis), mortality and mean survival time. Anodal (+) iontophoresis of 0.4% Ara-T in a 0.1 M NaCl solution significantly suppressed HSV-1 skin infection, but the infection was not altered by topical application of 3% Ara-T. HSV-2 infection was refractory to both topical and iontophoretic application of Ara-T. This is the first report of the in vivo efficacy of Ara-T for HSV-1 skin infections.

Herpes simplex virus recovery in neural tissues after ocular HSV shedding induced by epinephrine iontophoresis to the rabbit cornea

Ocular HSV-1 shedding from latently infected rabbits was induced by iontophoresis of 0.01% epinephrine into the eye. Anodal Iontophoresis of epinephrine was performed at 0.8 mAmps for 8 min once a day for 3 consecutive days. Shedding was determined by the presence of HSV-1 in the preocular tear film obtained via eye swabs. Bilateral epinephrine iontophoresis performed on selected days during 220-280 days after inoculation resulted in HSV-1 shedding in 75% of the eyes (30/40) and 100% of the rabbits (20/20). Following the induction of ocular HSV-1 shedding, rabbits were killed and selected neural tissues were homogenized. Cell-free preparations were assayed for the presence of infectious virions using primary rabbit kidney cell monolayers. When the tissues were homogenized immediately after death, virus was detected in only one neural tissue, the trigeminal ganglia. However, when the tissues were incubated in vitro for 18-24 hours prior to the homogenization, infectious HSV-1 was recovered from homogenates of the trigeminal ganglion, superior cervical ganglion, the ophthalmic branch of the trigeminal nerve, and the root entry zone of the trigeminal nerve. A relationship was noted between the time of the last ocular shedding and recovery of infectious HSV from the tissue homogenates. Furthermore, a positive correlation in 11 eyes between the recovery of HSV-1 from the perocular tear film and HSV-1 recovery from one or more corresponding neural tissues was found. These results suggested that epinephrine iontophoresis to the cornea triggered an "alteration" in the state of the virus in the neural tissues of the latently infected rabbits and that the change can be related to the induced ocular shedding.

Acyclovir and vidarabine monophosphate: comparison of iontophoretic and intravenous administration for the treatment of HSV-1 stromal keratitis

We determined the therapeutic efficacy of iontophoretic application of acyclovir and vidarabine monophosphate (ara-AMP) for the treatment of herpes simplex virus (HSV) type 1-induced stromal keratitis in rabbits. The therapeutic efficacy of intravenous administration of acyclovir was assessed in the same model. Stromal keratitis was produced by intrastromal injection of 10 microliters purified HSV-1, McKrae strain. Treatment began the first day after intrastromal injection. Iontophoresis (0.5 mAmp for four minutes) of 3.4 percent (0.1 M) ara-AMP and 5.0 percent (0.22 M) acyclovir was performed once daily for five consecutive days in two treatment groups. Intravenous administration of 50 mg acyclovir/kg was performed twice daily for eight consecutive days. Intravenous administration of NaCl (0.14 M) and ocular iontophoresis of NaCl (0.14 M) were performed as controls in the two treatment groups. At least two scorers performed a single masked evaluation of the disease severity (lesion scoring) of the conjunctiva, corneal epithelium, stroma, and iris by still lamp examination. The eyes were scored daily for 12 consecutive days, and then every other day up to day 22. Iontophoresis of acyclovir or ara-AMP significantly reduced the course of the disease compared with iontophoresis of NaCl. Intravenous administration of acyclovir significantly reduced the disease compared with intravenous NaCl. This suggests that iontophoresis of acyclovir or ara-AMP either alone or in combination with intravenous administration of acyclovir may be of value in the treatment of HSV-1 stromal keratitis.

Induction of ocular herpes simplex virus shedding by iontophoresis of epinephrine into rabbit cornea

Ocular herpes simplex virus type 1 (HSV-1) shedding from the latently infected rabbit was induced by iontophoresis of 0.01% epinephrine into the eye. The iontophoresis of epinephrine was at 0.8 mAmp for 8 min once a day for 3 consecutive days. Shedding was determined by the presence of HSV-1 in the tear film obtained with eye swabs. Unilateral epinephrine iontophoresis performed 60 days after inoculation of the virus resulted in ipsilateral HSV-1 shedding in all cases (7/7). Bilateral epinephrine iontophoresis performed on selected days during 170 to 365 days after inoculation resulted in HSV-1 shedding in 75% of the eyes (21/28) and 100% of the rabbits (14/14). All shedding was initiated within 3 days after the third treatment with epinephrine iontophoresis. The shedding frequency induced by epinephrine iontophoresis was significantly higher (pb less than 0.05) than that induced by the other methods employed. HSV-1 was detected in one or both cocultivated explants of trigeminal and superior cervical ganglia for every eye in all experimental groups, indicating that all eyes had the potential to shed. In conclusion, epinephrine iontophoresis induced ocular HSV-1 shedding reliably and with a high frequency in the latently infected rabbits. Furthermore, we suggest that this easily reproducible model of viral shedding offers a system for studying the factors involved in recurrent HSV-1 ocular infections.

Effect of iontophoretic and topical application of antiviral agents in treatment of experimental HSV-1 keratitis in rabbits

Cathodal (-) iontophoresis of 9-beta-D-arabinofuranosyl-adenine 5'-monophosphate (vidarabine monophosphate; Ara-AMP) was performed once daily for 3 days for the treatment of experimental herpes simplex virus type 1 (HSV-1) keratitis in rabbit eyes, and the therapeutic efficacy was compared with that of topical treatment of Ara-AMP and idoxuridine (IDU) administered five times daily for 4 days. With the treatment initiated 24 hr after viral inoculation, Ara-AMP cathodal iontophoresis resulted in significant suppression of epithelial and anterior segment disease processes. Topical IDU (0.5%) or Ara-AMP (10%) also significantly improved the disease process when compared to the placebo-treated group; however, iontophoresis of Ara-AMP resulted in a more marked improvement. Slit-lamp examination indicated that iontophoresis did not cause any observable pathologic changes in corneal epithelium, stroma, conjunctiva, or iris of rabbit eyes. This experiment suggests that iontophoresis of Ara-AMP is a safe and effective approach for preventing the development of herpes simplex keratitis in rabbits.

Iontophoretic application of adenine arabinoside monophosphate to herpes simplex virus type 1-infected hairless mouse skin

Several antiviral agents were applied topically or by iontophoresis to hairless mouse skin inoculated with herpes simplex virus type 1 (HSV-1), and the chemotherapeutic effectiveness was evaluated. Topical application of iododeoxyuridine, arabinoside A, and adenine arabinoside monophosphate (ara-AMP) moderately decreased the average lesion score, number of mice with paralysis, and number of mice dying in HSV-1-infected animals. Also, the mean survival time was moderately prolonged by topical application of those antiviral agents. When ara-AMP was applied by cathodal (-) iontophoresis to the HSV-1-infected skin, the average lesion score, number of mice with paralysis, and number of mice dying were greatly decreased. Furthermore, the mean survival time of mice was highly increased by cathodal (-) iontophoresis of ara-AMP. The therapeutic efficacy of ara-AMP iontophoresis was much superior to the topical application of iododeoxyuridine, arabinoside A, and ara-AMP. These data suggest that ara-AMP iontophoresis would be the method of choice for the management of HSV-1 skin lesions in hairless mice.