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Purpose: A clinical vaccine that protects from ocular herpes simplex virus type 1 (HSV-1) infection and disease still is lacking. In the present study, preclinical vaccine trials of nine asymptomatic (ASYMP) peptides, selected from HSV-1 glycoproteins B (gB), and tegument proteins VP11/12 and VP13/14, were performed in the "humanized" HLA-transgenic rabbit (HLA-Tg rabbit) model of ocular herpes. We recently reported that these peptides are highly recognized by CD8+ T cells from "naturally" protected HSV-1-seropositive healthy ASYMP individuals (who have never had clinical herpes disease)., Methods: Mixtures of three ASYMP CD8+ T-cell peptides derived from either HSV-1 gB, VP11/12, or VP13/14 were delivered subcutaneously to different groups of HLA-Tg rabbits (n = 10) in incomplete Freund's adjuvant, twice at 15-day intervals. The frequency and function of HSV-1 epitope-specific CD8+ T cells induced by these peptides and their protective efficacy, in terms of survival, virus replication in the eye, and ocular herpetic disease were assessed after an ocular challenge with HSV-1 (strain McKrae)., Results: All mixtures elicited strong and polyfunctional IFN-γ- and TNF-α-producing CD107+CD8+ cytotoxic T cells, associated with a significant reduction in death, ocular herpes infection, and disease (P < 0.015)., Conclusions: The results of this preclinical trial support the screening strategy used to select the HSV-1 ASYMP CD8+ T-cell epitopes, emphasize their valuable immunogenic and protective efficacy against ocular herpes, and provide a prototype vaccine formulation that may be highly efficacious for preventing ocular herpes in humans.

PURPOSE. The authors recently reported that Foxp3(+)CD4(+) CD25(+(Bright)) "natural" regulatory T cells (nT(reg) cells) are abundant in rabbit conjunctiva and suppress herpes simplex virus (HSV)-1-specific CD4(+) and CD8(+) effector T cells (T(eff) cells). However, little is known about the overall regulatory mechanisms of these nT(reg) cells. The authors investigate the regulation of conjunctiva-resident nT(reg) cells through Toll-like receptors (TLRs) and their effect on ocular mucosal T(eff) cell immunity. METHODS. CD4(+)CD25(+) nT(reg) cells were purified from naive rabbit conjunctivas, and their TLR expression profile was determined. The effects of TLR engagement on nT(reg) cell-mediated suppression of CD4(+) T(eff) cells were determined in vitro and in vivo. RESULTS. The authors found that conjunctiva-resident nT(reg) cells express high levels of TLR2 and TLR9; exposure to the TLR2 ligand lipoteichoic acid (LTA) led to the increased activation and proliferation of nT(reg) cells, and the addition of autologous APCs further increased nT(reg) cell expansion; in contrast, the TLR9 ligand CpG(2007) inhibited the proliferation of nT(reg) cells, and the addition of autologous APCs had no effect on such inhibition; nT(reg) cells treated with LTA, but not with CpG(2007), expressed IFN-γ and IL-10 mRNA, but not TGF-β; consistent with in vitro data, rabbits immunized by topical ocular drops of HSV-gD peptides + TLR2 ligand (LTA) displayed enhanced CD4(+)CD25(-) T(eff) cell immune responses when compared with HSV-gD peptides + TLR9 ligand (CpG(2007)). CONCLUSIONS. Although conjunctiva-resident CD4(+)CD25(+) nT(reg) cells express high level of TLR2 and TLR9, their suppressive function is more significantly reversed after the administration of TLR2 ligand (LTA; P < 0.005) than of TLR9 ligand (CpG(200); P > 0.005). These findings will likely help optimize the topical ocular administration of immunotherapies.

Purpose: To determine mitochondrial (mt)DNA variants in AMD and age-matched normal retinas., Methods: Total DNA was isolated from retinas (AMD, n = 13; age-matched normal, n = 13), choroid (AMD, n = 3), and blood (AMD, n = 138; normal, n = 133). Long-extension-polymerase chain reaction amplified the full-length ( approximately 16.2 kb) mtDNA genome. Retinal mtDNA was sequenced for nucleotide variants and length heteroplasmy. Pyrosequencing was performed on heteroplasmic mtDNA. PCR amplification and enzyme digestions were used to analyze for nucleotide changes., Results: Retinal mtDNA had a greater number of rearrangements and deletions than did blood mtDNA in normal samples (9.3 +/- 1.78 vs. 3 +/- 1.18, P = 0.019), and AMD samples (14.33 +/- 1.96 vs. 5.2 +/- 0.80, P = 0.0031. Five (55%) of 9 AMD patients had unreported SNPs, and 2 (16.6%) of 12 of the normal group did. The mtDNA coding region had 20 SNPs that produced amino acid changes. The noncoding MT-Dloop region had nucleotide heteroplasmy and length heteroplasmy. There were more SNPs per person in the AMD population than in the older (P = 0.003) and younger (P = 0.05) normal subjects. The C12557T (T-I) in the MT-ND5 gene was present in two AMD subjects (2/138) but was absent in the normal (0/133). Common mutations for Leber's hereditary optic neuropathy (LHON: G11778A; T14484C; and G3460A) were not present in AMD samples., Conclusions: AMD subjects have high levels of large mtDNA deletions/rearrangements in the retinas, unreported and amino acid-changing SNPs in the coding genome, and a greater number of SNPs per person in the noncoding MT-Dloop region. These mtDNA variants could diminish energy production efficiency, alter the mtDNA copy numbers and/or impact transcription in AMD retinas.

Purpose: To examine the mtDNA control regions in normal and age-related macular degeneration (AMD) retinas. To identify the mtDNA variations associated with AMD., Methods: Retinas from 10 normal and 11 AMD globes were isolated and analyzed for mtDNA rearrangements by long extension-polymerase chain reaction (LX-PCR) and for the nature and frequency of single-nucleotide polymorphisms (SNPs) in the mtDNA control region by direct sequencing. Blood DNA was extracted from 99 AMD and 92 age-matched control subjects. The sequence variations that define haplogroups H, I, J, K, T, V, X, and U were characterized by PCR, restriction enzyme digestion, and/or sequencing., Results: LX-PCR of retinal mtDNAs revealed high levels of rearrangements in the patients with AMD and the control subjects, consistent with the decline in mitochondrial function with age. However, the AMD retinas had higher oxidized DNA levels and a higher number of SNPs than controls (P = 0.02). The control region SNPs T16126C and A73G, commonly found in haplogroups J and T, were more frequent in the AMD retinas than in normal retinas. The associations between AMD and haplogroups J and T were confirmed and extended by analysis of blood DNA. SNPs at position a T16126C (J; odds ratio [OR] = 3.66), T16126C+G13368A (JT; OR = 10.27), A4917G+A73G (T4; OR = 5), and T3197C+A12308G (U5; OR = infinity), were all strongly associated with AMD., Conclusions: AMD retinas exhibited increased mtDNA control region SNPs compared to normal retinas. This correlated with an increased frequency of mtDNA SNPs associated with haplogroups J, T and U in patients with AMD. These results implicate mitochondrial alterations in the etiology of AMD.

Purpose: An important phase in the development of an ocular herpes simplex virus type 1 (HSV-1) subunit vaccine is the identification of an efficient, safe, and adjuvant-free antigen delivery system capable of inducing and sustaining long-term memory T-cell protective immunity. This study was conducted to test the hypothesis that immunization with self-adjuvanting lipopeptide bearing HSV-1 glycoprotein D (gD) T-cell epitopes would elicit long-term HSV-specific T cells and decrease infection, disease, or both in a ocular herpes mouse model., Methods: Five immunodominant CD4(+) T-cell peptide epitopes (gD(1-29), gD(49-82), gD(146-179), gD(228-257), and gD(332-358)), recently identified from HSV-1 gD, were covalently linked to a palmitic acid moiety (lipopeptides) and delivered subcutaneously in adjuvant-free saline. The primary and memory T cells induced by these molecularly defined lipopeptides and their protective efficacy were assessed, in terms of virus replication in the eye, ocular disease, and survival., Results: Three gD lipopeptides, that drive dendritic cell maturation in vitro, induced long-term, virus-specific, IFN-gamma-producing CD4(+) Th(1) responses, associated with a reduction in ocular herpes infection and disease. Immunization with a cocktail of these three highly immunogenic Th(1) lipopeptides increased survival, lowered the peak of ocular virus titer, and cleared the ocular disease., Conclusions: Vaccination with a mixture self-adjuvanting lipopeptides containing novel HSV-1 immunodominant gD T-cell epitopes protected mice from ocular herpes infection and disease. The strength of protective immunity induced by these lipopeptides together with their safety provide a molecularly defined vaccine formulation that could combat ocular herpes infection and disease in humans.

Purpose: To assess the relative impact of antibodies specific for HSV-1 glycoproteins on eye disease in response to HSV-1 infection, the composition of antibodies specific for 10 of the viral glycoproteins, and the effect of anti-glycoprotein (g)D and anti-gK antibodies on antibody-dependent enhancement (ADE)., Methods: In a prospective case-control study, sera from patients with a history of herpes stromal keratitis (HSK) were compared with sera from nonocular HSV-1-seropositive and HSV-seronegative control subjects. HSV-1 neutralizing antibody titer and type-specific IgG and IgM were measured. In addition, the presence of anti-HSV-1 gD and gK antibodies in the sera of all patients also was determined by ELISA using gD and gK antigens. Finally, the role of anti-gD- and gK-specific antibodies to ADE was investigated., Results: Average neutralizing antibody titers and levels of HSV-1 IgG were similar between HSK- and non-HSK-seropositive patients. However, the contribution of gD to the neutralizing antibody titer in HSK sera was significantly lower than that in non-HSK-seropositive patients, despite higher anti-gD ELISA titers. Overall, sera from patients with HSK had higher anti-gK antibody titers and induced ADE in vitro compared with non-HSK or seronegative sera. The ADE response in HSK sera was attributed to anti-gK antibody., Conclusions: These results suggest that sera from HSK patients had higher anti-gD and -gK antibody titers than sera from seropositive patients who had no history of HSK despite similar levels of neutralizing antibody titers and HSV-1 IgG, that HSK sera induced ADE whereas sera from non-HSK patients did not induce ADE, and that anti-gD antibody in sera of HSK patients contributed less to the HSV-1 neutralization antibody titer than did sera from non-HSK patients.

Purpose: To screen superoxide dismutase 1 (SOD1) on chromosome 21 as a possible candidate gene for familial keratoconus (KC)., Methods: Total genomic DNA was extracted from the blood of 15 different KC families and 156 unaffected subjects. All five exons of the SOD1 gene were sequenced. For a rapid screening test, DNA was amplified by polymerase chain reaction (PCR), digested with HpyCH4 III or analyzed by radioactively end-labeled exon PCR. RNA was extracted from leukocytes and reverse transcribed to cDNA, and the PCR was amplified for splice variants. Some samples were cloned and sequenced., Results: A heterozygous genomic 7-base deletion in intron 2 of the SOD1 gene was identified in two KC families (pedigrees 1 and 6). The deletion segregated within pedigree 1 and was absent in 312 chromosomes from normal individuals. RNA from the proband of pedigree 1 showed that in addition to the wild-type transcript, two other transcripts were expressed for the CuZn SOD (SOD1) gene: lacking entire exon 2 (LE2) and lacking entire exon 2 and entire exon 3 (LE2E3)., Conclusions: A unique genomic deletion within intron 2 close to the 5' splice junction of the SOD1 gene was identified in three patients with KC. Moreover, mRNA from one affected individual also had two transcript splice variants (LE2 and LE2E3) that others have shown to code for proteins lacking the active site of the SOD1 enzyme. Further studies should be conducted to determine whether a causal relationship exists between these two events that may increase oxidative stress and be associated with KC.

Purpose: To investigate the therapeutic efficacy of periocular vaccination with herpes simplex virus (HSV) recombinant glycoprotein D from HSV-1 (gD1) or HSV-2 (gD2) in decreasing HSV-induced recurrent dendritic keratitis and HSV-induced recurrent ocular shedding in rabbits latently infected with HSV-1., Methods: Rabbits latently infected with HSV-1 were vaccinated periocularly (by subconjunctival injection) with gD1 and adjuvant, gD2 and adjuvant, or adjuvant alone. Eyes were examined daily for 49 days for recurrent herpetic keratitis and for recurrent infectious HSV-1 shedding., Results: In both vaccinated groups, a significantly decreased number of eyes exhibited recurrences of herpetic keratitis compared with recurrences in adjuvant-treated control eyes (gD1 group, 27/1372, [2%]; gD2 group, 24/1274, [2%]; and control, 54/1274 [4%]; P < 0.005). Eyes in the gD1-vaccinated group (44/1308 [3.4%]; P = 0.01), but not those in the gD2-vaccinated group (71/1274 [5.6%]; P = 0.93), had significantly decreased viral shedding (positive cultures compared with total cultures) compared with eyes in the adjuvant-treated control group (69 of 1275 [5.4%])., Conclusions: Recurrent HSV-1 corneal disease was significantly reduced by therapeutic local periocular vaccination. The vaccine may be more efficacious against HSV-1-induced recurrent corneal disease than against recurrent HSV-1 ocular shedding. Its efficacy against corneal disease appeared to be longer lasting than its efficacy against recurrent spontaneous shedding. The heterotypic gD2 vaccine was as efficacious as the homotypic gD1 vaccine against recurrent corneal disease, whereas the homotypic vaccine was much more efficacious than the heterotypic vaccine against recurrent HSV-1 shedding. This is the first report in any animal model of a successful therapeutic vaccine against recurrent HSV-1-induced corneal disease. These results support the concept that development of a therapeutic vaccine for ocular HSV-1 recurrence in humans may be possible.

Purpose: To determine whether the exacerbation of herpes simplex virus type-1 (HSV-1) induced corneal scarring that the authors reported previously in HSV-1 glycoprotein K (gK) vaccinated BALB/c mice challenged with HSV-1 strain McKrae was a general phenomenon independent of virus and mouse strains. To determine the gK-induced immune response leading to exacerbation of HSV-1-induced corneal scarring., Methods: BALB/c or C57BL/6 mice were vaccinated with gK, ocularly challenged with HSV-1 strain KOS or McKrae, and the relative amount of corneal scarring determined 28 days after challenge. The T cells, total serum, or purified immunoglobulin G (IgG) isolated from gK-vaccinated mice was transferred individually to naive mice, and the affects on corneal scarring after HSV-1 challenge were determined., Results: The KOS challenge of gK-vaccinated BALB/c mice resulted in significant corneal scarring (P = 0.0003), despite the fact that KOS normally produces no corneal scarring. McKrae challenge of gK-vaccinated C57BL/6 mice resulted in significant corneal scarring (P < 0.0001), despite the fact that C57BL/6 mice are normally refractory to HSV-1-induced corneal scarring. Passive transfer of total anti-gK mouse sera or purified anti-gK mouse IgG, but not adoptive transfer of total anti-gK T-cells to naive mice, resulted in exacerbation of corneal scarring after HSV-1 challenge (P < 0.0001). Mice defective for T-cell-dependent antibody production were not susceptible to exacerbation of HSV-1-induced corneal scarring by gK vaccination (P < 0.0001)., Conclusions: The ability of gK vaccination to exacerbate HSV-1-induced corneal scarring was not mouse strain or HSV-1 strain specific. The gK-induced exacerbation of corneal scarring was related to anti-gK IgG. How anti-gK IgG exacerbated HSV-1 induced corneal scarring remains to be determined.

Purpose: To uncover abnormalities of extracellular matrix (ECM) distribution in human corneas with pseudophakic and aphakic bullous keratopathy (PBK/ABK)., Methods: Indirect immunofluorescence with antibodies to 27 ECM components was used on frozen sections of 14 normal and 20 PBK/ABK corneas., Results: Fibrillar deposits of an antiadhesive glycoprotein tenascin in the anterior and posterior stroma, epithelial basement membrane (BM), bullae and subepithelial fibrosis (SEF) areas, and posterior collagenous layer (PCL) were revealed in disease corneas. Tenascin in midstroma, which was observed in some cases, correlated with decreased visual acuity. In normal central corneas, tenascin was never found. Other major ECM abnormalities in PBK/ABK corneas compared to normals included: discontinuous epithelial BM straining for laminin-1 (alpha 1 beta 1 gamma 1), entactin/nidogen and fibronectin; accumulation of fibronectin and alpha 1-alpha 2 type IV collagen on the endothelial face of the Descemet's membrane; and abnormal deposition of stromal ECM (tenascin, fibronectin, decorin, types I, III, V, VI, VIII, XII, XIV collagen) and BM components (type IV, collagen, perlecan, bamacan, laminin-1, entactin-nidogen, fibronectin) in SEF areas and in PCL., Conclusions: The study provides a molecular description of an ongoing fibrosis on the epithelial, stomal, and endothelial levels in PBK/ABK corneas. These fibrotic changes may follow initial endothelial damage after cataract surgery, may be caused by the upregulation of fibrogenic cytokines, and may play a significant role in the progression of bullous keratopathy.

Purpose: To compare the efficacy of each of seven expressed herpes simplex virus 1 (HSV-1) glycoproteins as vaccines to protect against ocular disease after primary ocular HSV-1 infection., Methods: Mice were vaccinated three times with equal amounts of each of seven individually expressed HSV-1 glycoproteins (gB, gC, gD, gE, gG, gH, and gI) and then ocularly challenged with McKrae, a corneal disease-producing strain of HSV-1. Viral clearance from the eye, blepharitis, keratitis, and neovascularization were determined at various times after infection., Results: Mice vaccinated with gD or gB had the best protection against eye disease. Vaccination with gI, gC, or gE produced moderate protection against eye disease. Vaccination with gG produced less protection, and vaccination with gH produced no apparent protection against eye disease., Conclusions: These results suggest that when used as vaccines, different HSV-1 glycoproteins provide different levels of protection against HSV-1-induced eye disease. Based on comparison with the authors' previously published results, the ability of each glycoprotein to protect against eye disease correlated with the ability of the glycoprotein to induce high serum neutralizing antibody titers and killer cell activity. Results suggest that the effectiveness of these seven glycoproteins in protecting against eye disease can be ranked as follows: gD > gB > gI > (gC = gE) > gG > gH.

Purpose: To address the possibility of neuronal-like herpes simplex virus type 1 (HSV-1) latency in the cornea by determining if regulation of the HSV-1 LAT promoter in stromal keratocytes is similar to LAT promoter regulation in neurons., Methods: Transient chloramphenicol acetyltransferase (CAT) assays were used to measure the relative promoter activity of various HSV-1 LAT promoter fragments in primary human corneal cells versus neuronal and nonneuronal cells., Results: The authors found that the LAT promoter, whose location they previously mapped in neurons using transient CAT assays, functioned in stromal keratocytes using the same assay system and that two regions between -283 and -1932 nucleotides relative (upstream) to the start of LAT transcription slightly increased the LAT promoter activity in stromal keratocytes. They previously showed a similar increase in neuronal cells, and a large decrease in nonneuronal cells. In addition, they found that a neuronal specific enhancer region they previously defined between -162 and -283 nucleotides upstream of the start of LAT transcription also enhanced promoter activity in stromal keratocytes. Using gel-shift assays, they detected a nuclear factor specific to neurons and stromal keratocytes that binds to the LAT promoter and that may be a LAT regulatory factor., Conclusions: Recently, it has been suggested that the cornea might serve as an alternative site of latent herpes simplex virus type 1 (HSV-1) infection. However, this remains controversial. The authors' findings suggest that corneal and neuronal cells regulate the LAT promoter similarly and that this regulation differs from that seen in nonneuronal cells. Thus, the possibility of neuronal-like latency in the cornea remains plausible.

One potential complication of systemic herpes simplex virus (HSV) vaccination is that subsequent ocular infection may lead to increased immunogenic corneal scarring. Therefore, V52, a genetically engineered vaccinia virus that expresses the HSV-1 glycoprotein gD, was tested for ocular safety and for protection against ocular challenge with a stromal-disease-producing strain (McKrae) of HSV-1. To maximize immune response, rabbits were vaccinated by a series of inoculations. V52-vaccinated rabbits developed significant HSV-1 neutralizing antibody titers; however, they were not as high as those induced by vaccination with live HSV-1 McKrae. One month after the final vaccination, all rabbits were challenged ocularly. Eyes were monitored for 35 days for epithelial keratitis, stromal keratitis, and iritis. In no case was epithelial keratitis, stromal keratitis, or iritis significantly exacerbated by vaccination. The gD V52 recombinant vaccine provided protection against HSV-1 induced epithelial keratitis (P = 0.02) and long-term stromal scarring (P = 0.04). There was no significant reduction in the incidence of trigeminal ganglionic latency in the vaccinated rabbits (P greater than 0.05). Thus, our results indicate that V52, a gD recombinant vaccine probably is safe with regard to corneal scarring, and may provide a small amount of protection against ocular HSV-1 infection. The amount of protection provided was less than that reported in mice and guinea pigs. This suggests that to provide high levels of ocular protection in rabbits (and probably in humans), HSV-1 vaccines may have to elicit a more vigorous immune response than that produced by normal HSV-1 infection.

Recombinant human interferon (IFN) alpha A and alpha D combined with 1% trifluridine ophthalmic solution gave beneficial results when applied topically at a dose of 1 x 10(6) U per eye four times a day commencing 4 hr after eyes were inoculated with herpes simplex virus (HSV-1). Acute herpetic keratitis was suppressed by trifluridine alone and the combined therapies, but the high-titered interferon preparations, alone, had little effect. Duration of HSV-1 shedding into tear film during topical treatment for acute herpetic keratitis was reduced slightly by combined therapy with either IFN alpha A or IFN alpha D with trifluridine.

2-Fluoro-5-iodo-ara-C (FIAC), a new and potent drug, was tested for antiviral activity against several strains of herpes simplex virus (HSV), types 1 and 2. Effective dose-50% (ED-50) determinations for FIAC ranged from 0.023 to 0.51 muM for HSV-2. FIAC-treated cells did not exhibit any toxicity until the drug concentration was increased 2000-fold above the ED-50 level. Ocular herpetic keratitis in New Zealand white rabbits was treated with 1.0%, 0.1%, 0.01% FIAC beginning 3 days after inoculation wit HSV-1 (McKrae strain). Topical chemotherapy was administered five times per day for 7 consecutive days. After 4 days of treatment, corneal epithelial involvement, conjunctivitis, iritis, and clouding were not detectable in eyes receiving 1.0% FIAC. Toxic reactions were not observed in rabbit eyes treated with FIAC drug. HSV was not prevented from spreading into the central nervous system when topical FIAC therapy was initiated on day 3 after inoculation.

The rabbit ocular model was used to determine if flurbiprofen, a new nonsteroidal antiinflammatory agent, caused exacerbation of herpes simplex virus (HSV) infection. Acute ocular HSV infections treated with flurbiprofen (0.1%) or dexamethasone (0.1%) drops four times a day for 10 days were similar in severity and duration as measured by corneal lesions, conjunctivitis, and corneal clouding. Eyes receiving placebo healed more rapidly than eyes treated with either anti-inflammatory drug. This preliminary study suggests that flurbiprofen appears to be comparable with dexamethasone in clinical exacerbation of acute ocular HSV infection.

Acyclovir, a new potent antiviral drug, was used to treat herpes simplex virus (HSV) infection in the rabbit ocular model. Acyclovir (3% ointment) used topically one to five times a day on acute ocular HSV infection gave beneficial results as measured by a reduction in corneal involvement, conjunctivitis, iritis, and corneal clouding. Topical treatment did not prevent the establishment of latent HSV infection. Intravenous acyclovir used two times a day (50 mg/kg) on rabbits with latent HSV infection appeared to suppress HSV in the nervous system but did not eradicate established latent HSV infection.

Iontophoresis of epinephrine into the cornea of previously infected mice was used in an attempt to induce reactivation of latent herpes simplex virus (HSV) infection of the trigeminal ganglia. BALB/c mice infected with HSV-1 strain McKrae following corneal scarification developed a latent infection of the trigeminal ganglia within 15 days. At 28 days postinfection, mice were subjected to a 3-day cycle of iontophoresis of epinephrine (0.01%) into the cornea. Ocular shedding of HSV occurred in 16/23 (70%) of stimulated mice; these animals did not shed HSV in the 3-day period prior to iontophoresis. Spontaneous shedding of HSV, however, was noted in 3/97 (3%) mice not subjected to epinephrine iontophoresis. "Infectious" virus was isolated only from the trigeminal ganglia of stimulated mice, whereas "latent" virus was isolated from the trigeminal ganglia of both stimulated and nonstimulated mice. All virus isolates were verified to be HSV by neutralization with a known HSV-1 antiserum. This ocular system thus allows for the study of the full spectrum of latent HSV infections, including latency, ganglionic reactivation, and peripheral virus shedding.

Effects of topical acyclovir treatment on rabbit eyes infected with parent McKrae, idoxuridine-resistant, and vidarabine-resistant strains of HSV-1 were studied. Topical acyclovir therapy given four times a day was significantly more effective than idoxuridine and vidarabine at suppressing acute herpetic ocular disease induced by either sensitive or drug-resistant strains of HSV-1. Virus isolation from neural tissues indicated that none of the therapy prevented viral infection of the nervous system.