Cutaneous Herpes Simplex Virus Type Research Articles

Peptide Inhibitor of Complement C1, RLS-0071, Reduces Zosteriform Spread of Herpes Simplex Virus Type 1 Skin Infection and Promotes Survival in Infected Mice.

Herpes simplex virus type 1 (HSV-1) is a prevalent human pathogen primarily transmitted through skin-to-skin contact, especially on and around mucosal surfaces where there is contact with contaminated saliva during periods of viral shedding. It is estimated that 90% of adults worldwide have HSV-1 antibodies. Cutaneous HSV-1 infections are characterized by a sensation of tingling or numbness at the initial infection site followed by an eruption of vesicles and then painful ulcers with crusting. These symptoms can take ten days to several weeks to heal, leading to significant morbidity. Histologically, infections cause ballooning degeneration of keratinocytes and formation of multinucleated giant cells, ultimately resulting in a localized immune response. Commonly prescribed treatments against HSV-1 infections are nucleoside analogs, such as acyclovir (ACV). However, the emergence of ACV-resistant HSV (ACVR-HSV) clinical isolates has created an urgent need for the development of compounds to control symptoms of cutaneous infections. RLS-0071, also known as peptide inhibitor of complement C1 (PIC1), is a 15-amino-acid anti-inflammatory peptide that inhibits classical complement pathway activation and modulates neutrophil activation. It has been previously shown to aid in the healing of chronic diabetic wounds by inhibiting the excessive activation of complement component C1 and infiltration of leukocytes. Here, we report that treatment of cutaneous infections of HSV-1 and ACVR-HSV-1 in BALB/cJ mice with RLS-0071 significantly reduced the rate of mortality, decreased zosteriform spread, and enhanced the healing of the infection-associated lesions compared to control-treated animals. Therefore, RLS-0071 may work synergistically with other antiviral drugs to aid in wound healing of HSV-1 cutaneous infection and may potentially aid in rapid wound healing of other pathology not limited to HSV-1.

Pluronic F127-tailored lecithin organogel of acyclovir: preclinical evidence of antiviral activity using BALB/c murine model of cutaneous HSV-1 infection.

Herpes is a well-known contagious infection equally affecting both sexes. Among many antiviral drugs employed for its treatment, acyclovir (ACY) is the drug of choice. The currently available therapies of ACY suffer from limitations like poor oral bioavailability (10-15%) and high-dose requirement. The present scientific study aims to explore pluronic lecithin organogel (PLO) as a novel drug delivery platform for ACY to bring an improvement in its delivery through topical route. The properties of organogel like biocompatibility and amphiphilic nature which facilitates dissolution of various drugs of different solubility characteristics along with enhancing the permeation potential of active molecules make it a favorable drug delivery platform for the management of topical diseases. The developed PLO formulations were characterized for micromeritic characteristics, viz., zeta potential, percentage drug content, organogel morphology, skin permeation, retention, and stability studies. The selected topical formulation was further compared with the marketed one for its therapeutic efficacy by inducing cutaneous Herpes simplex virus type 1 infection followed by confirmation of viral load by immunofluorescence and PCR analyses. The developed formulation showed significant improvement over the marketed product as reflected in lesion scoring index and PCR analysis. Further, it proved better to the marketed formulation in t.i.d. treatment regimen in comparison to control. The improvement in overall performance leading to enhanced bioavailability and safety is attributed to the synergism between excipient properties and formulation characteristics. The drug ACY in this micro environment not only finds an improved delivery vehicle but it also offers enhanced drug-target interactions.

Evaluation of ocean biomass products that activate cell-medicated immunity in mice cutaneously infected with herpes simplex virus type 1

We screened and evaluated the activation of cell-medicated immunity by ocean biomass products using a cutaneous herpes simplex virus type 1 (HSV-1) infection model. In this model, a delayed-type hypersensitivity (DTH) associated with cell-mediated immunity is an important immune defense systems. An aqueous fraction of ovary of Seriola quinqueradiata (A-SQ) or a lipophilic fraction of head and internal organs of Hymenocephalus lethonemus (L-HL) was administered orally to mice infected with HSV-1 three times daily during 8 days (days 0 to 7) after infection. They delayed the progress of herpetic skin lesions without toxicity and significantly increased the DTH reaction to inactivated HSV-1 antigen on the footpads of infected mice. Further, A-SQ and L-HL increased the production of interferon-γ from splenocytes of HSV-1-infected mice by the inactivated-HSV-1. Thus, the efficacies of A-SQ and L-HL against HSV-1 infection may be due to the augmentation of cell-mediated immunity through DTH reaction.

Neuroimmune-Glia Interactions in the Sensory Ganglia Account for the Development of Acute Herpetic Neuralgia.

Herpetic neuralgia is the most important symptom of herpes zoster disease, which is caused by Varicella zoster Nevertheless, the pathophysiological mechanisms involved in herpetic neuralgia are not totally elucidated. Here, we examined the neuroimmune interactions at the sensory ganglia that account for the genesis of herpetic neuralgia using a murine model of Herpes Simplex Virus Type-1 (HSV-1) infection. The cutaneous HSV-1 infection of mice results in the development of a zosteriform-like skin lesion followed by a time-dependent increase in pain-like responses (mechanical allodynia). Leukocytes composed mainly of macrophages and neutrophils infiltrate infected DRGs and account for the development of herpetic neuralgia. Infiltrating leukocytes are responsible for driving the production of TNF, which in turn mediates the development of herpetic neuralgia through downregulation of the inwardly rectifying K+ channel Kir4.1 in satellite glial cells. These results revealed that neuroimmune-glia interactions at the sensory ganglia play a critical role in the genesis of herpetic neuralgia. In conclusion, the present study elucidates novel mechanisms involved in the genesis of acute herpetic pain and open new avenues for its control.SIGNIFICANCE STATEMENT Acute herpetic neuralgia is the most important symptom of herpes zoster disease and it is very difficult to treat. Using a model of peripheral infection of mice with HSV-1, we have characterized for the first time the neuroimmune-glia interactions in the sensory ganglia that account for the development of acute herpetic neuralgia. Among these mechanisms, leukocytes composed mainly of macrophages and neutrophils infiltrate infected sensory ganglia and are responsible for driving the production of TNF. TNF, via TNFR1, mediates herpetic neuralgia development through downregulation of the inwardly rectifying K+ channel Kir4.1 in satellite glial cells. This study elucidates novel mechanisms involved in the genesis of acute herpetic neuralgia and open new avenues for its control.

Diagnosis and treatment of herpes simplex 1 virus infection in pregnancy.

A nulliparous woman presented at 21 weeks' gestation with a 72-h history of a rash on her left arm. Initially isolated to the forearm, it had quickly spread, becoming multiple itchy fluid-filled blisters. Blood tests showed mild neutrophilia and raised CRP. Skin swabs demonstrated the presence of herpes simplex virus type 1 (HSV1) DNA. There was no history of previous HSV1 exposure. There is scant literature on uncomplicated cutaneous HSV1 since the majority is oral/genital. The incidence of transmission varies and is dependent on site of infection and immunological status. Type-specific serological testing is recommended to identify a primary first episode infection due to the 30-60% vertical transmission rate. Infection is associated with morbidity and mortality for both mother and fetus including maternal encephalitis, acute retinal necrosis, pneumonia and hepatitis. Neonatal disease can be congenital (cutaneous lesions, microcephaly, hydranencephaly, intracranial calcifications, chorioretinitis, microphthalmia and optic nerve atrophy) or acquired (skin, eyes and mouth disease or central nervous system disease or disseminated disease). Prophylactic aciclovir reduces the number of women with active genital lesions at the time of delivery. If primary infection occurs outside of the first trimester and active genital lesions are present, then vaginal delivery should be avoided. If infection has occurred in the first trimester, vaginal birth can be attempted even in the presence of active lesions. There is no available guidance on prophylactic treatment of non-genital HSV1 in pregnancy.

Neutrophils are dispensable in the modulation of T cell immunity against cutaneous HSV-1 infection

Neutrophils rapidly infiltrate sites of inflammation during peripheral infection or tissue injury. In addition to their well described roles as pro-inflammatory phagocytes responsible for pathogen clearance, recent studies have demonstrated a broader functional repertoire including mediating crosstalk between innate and adaptive arms of the immune system. Specifically, neutrophils have been proposed to mediate antigen transport to lymph nodes (LN) to modulate T cell priming and to influence T cell migration to infected tissues. Using a mouse model of cutaneous herpes simplex virus type 1 (HSV-1) infection we explored potential contributions of neutrophils toward anti-viral immunity. While a transient, early influx of neutrophils was triggered by dermal scarification, we did not detect migration of neutrophils from the skin to LN. Furthermore, despite recruitment of neutrophils into LN from the blood, priming and expansion of CD4+ and CD8+ T cells was unaffected following neutrophil depletion. Finally, we found that neutrophils were dispensable for the migration of effector T cells into infected skin. Our study suggests that the immunomodulatory roles of neutrophils toward adaptive immunity may be context-dependent, and are likely determined by the type of pathogen and anatomical site of infection.

Augmentation of T helper type 1 immune response through intestinal immunity in murine cutaneous herpes simplex virus type 1 infection by probiotic Lactobacillus plantarum strain 06CC2

We previously found that Lactobacillus plantarum strain 06CC2 showed probiotic potential, and its oral administration effectively induced Th1 cytokine production and activated the Th1 immune response associated with intestinal immunity in mice. In this study, to evaluate its potential as a versatile oral adjuvant for treatment of viral infection, we assessed the immunomodulatory activity of 06CC2 on murine cutaneous herpes simplex virus type 1 (HSV-1) infection, in which a major immune defense system is a delayed-type hypersensitivity (DTH) reaction based on activation of the Th1 immune response, in relation to its oral efficacy for alleviation of herpetic symptoms. In the HSV-1 infection model, oral administration of 06CC2 (20mg/mouse) twice daily for seven days starting two days before infection was significantly effective in delaying the development of skin lesions in the early phase of infection and reducing virus yields in the brain on day 4 after infection. In addition, 06CC2 significantly augmented the DTH reaction to inactivated HSV-1 antigen and elevated interferon (IFN)-γ production by HSV-1 antigen from splenocytes. On day 2, natural killer (NK) cell activity was significantly elevated, and the elevation was still observed on day 4. Furthermore, gene expressions of interleukin-12 receptor β2 and IFN-γ in Peyer's patches were augmented on day 4 by 06CC2 administration. Thus, 06CC2 was suggested to alleviate herpetic symptoms in mice in correlation with augmentation of the Th1 immune responses associated with NK cell activity through intestinal immunity. Strain 06CC2 may be a versatile oral adjuvant to activate Th1 immune response.

Activation of Cellular Immunity in Herpes Simplex Virus Type 1-Infected Mice by the Oral Administration of Aqueous Extract of Moringa oleifera Lam. Leaves.

Moringa oleifera Lam. is used as a nutritive vegetable and spice. Its ethanol extract has been previously shown to be significantly effective in alleviating herpetic skin lesions in mice. In this study, we evaluated the alleviation by the aqueous extract (AqMOL) and assessed the mode of its anti-herpetic action in a murine cutaneous herpes simplex virus type 1 (HSV-1) infection model. AqMOL (300 mg/kg) was administered orally to HSV-1-infected mice three times daily on days 0 to 5 after infection. AqMOL significantly limited the development of herpetic skin lesions and reduced virus titers in the brain on day 4 without toxicity. Delayed-type hypersensitivity (DTH) reaction to inactivated HSV-1 antigen was significantly stronger in infected mice administered AqMOL and AqMOL augmented interferon (IFN)-γ production by HSV-1 antigen from splenocytes of HSV-1-infected mice at 4 days post-infection. AqMOL administration was effective in elevating the ratio of CD11b(+) and CD49b(+) subpopulations of splenocytes in infected mice. As DTH is a major host defense mechanism for intradermal HSV infection, augmentation of the DTH response by AqMOL may contribute to their efficacies against HSV-1 infection. These results provided an important insights into the mechanism by which AqMOL activates cellular immunity. Copyright © 2016 John Wiley & Sons, Ltd.

Atypical Presentation of Exophytic Herpes Simplex Virus Type 2 With Concurrent Cytomegalovirus Infection

We report 3 unusual cases of atypical exophytic cutaneous herpes simplex virus (HSV) type 2 with concurrent cytomegalovirus (CMV) infection in immunosuppressed patients and raise awareness to the significant clinical and pathologic challenges in establishing the correct diagnosis. In all the 3 cases, the lesions presented as fungating plaques and nodules with areas of superficial erosion. Initial clinical differential included genital warts, syphilis, versus cutaneous malignancy. All the 3 patients were referred to the dermatology clinic where a combination of cutaneous biopsies, viral cultures of the lesions, polymerase chain reaction, CMV antigenemia, and immunoperoxidase stains for CMV and HSV confirmed the diagnosis of HSV type 2 with concurrent CMV infection. All the 3 patients were treated with oral valganciclovir with significant improvement noted at the follow-up visit. In addition, we review the previously reported HSV/CMV cutaneous coinfection cases.

Microemulsion-Based Oxyresveratrol for Topical Treatment of Herpes Simplex Virus (HSV) Infection: Physicochemical Properties and Efficacy in Cutaneous HSV-1 Infection in Mice

The physicochemical properties of the optimized microemulsion and the permeating ability of oxyresveratrol in microemulsion were evaluated, and the efficacy of oxyresveratrol microemulsion in cutaneous herpes simplex virus type 1 (HSV-1) infection in mice was examined. The optimized microemulsion was composed of 10% w/w of isopropyl myristate, 35% w/w of Tween 80, 35% w/w of isopropyl alcohol, and 20% w/w of water. The mean particle diameter was 9.67 ± 0.58nm, and the solubility of oxyresveratrol in the microemulsion was 196.34 ± 0.80mg/ml. After accelerated and long-term stability testing, the microemulsion base and oxyresveratrol-loaded microemulsion were stable. The cumulative amount of oxyresveratrol permeating through shed snake skin from microemulsion at 6h was 93.04 times compared to that of oxyresveratrol from Vaseline, determined at 20% w/w concentration. In cutaneous HSV-1 infection in mice, oxyresveratrol microemulsion at 20%, 25%, and 30% w/w, topically applied five times daily for 7days after infection, was significantly effective in delaying the development of skin lesions and protecting from death (p < 0.05) compared with the untreated control. Oxyresveratrol microemulsion at 25% and 30% w/w was significantly more effective than that of 30% w/w of oxyresveratrol in Vaseline (p < 0.05) and was as effective as 5% w/w of acyclovir cream, topically applied five times daily (p > 0.05). These results demonstrated that topical oxyresveratrol microemulsion at 20-30% w/w was suitable for cutaneous HSV-1 mouse infection.

Disseminated cutaneous Herpes Simplex Virus-1 in a woman with rheumatoid arthritis receiving Infliximab: A case report

IntroductionWe present the case of a 49-year-old woman with a seronegative rheumatoid arthritis who developed pustular psoriasis whilst on etanercept and subsequently developed disseminated herpes simplex on infliximab.Case presentationOur patient presented with an inflammatory arthritis which failed to respond to both methotrexate and leflunomide, and sulphasalazine treatment led to side effects. She was started on etanercept but after 8 months of treatment developed scaly pustular lesions on her palms and soles typical of pustular psoriasis. Following the discontinuation of etanercept, our patient required high doses of oral prednisolone to control her inflammatory arthritis. A second biologic agent, infliximab, was introduced in addition to low-dose methotrexate and 15 mg of oral prednisolone. However, after just 3 infusions of infliximab, she was admitted to hospital with a fever, widespread itchy vesicular rash and worsening inflammatory arthritis. Fluid from skin vesicles examined by polymerase chain reaction showed Herpes Simplex Virus type 1. Blood cultures were negative and her chest X-ray was normal. Her infliximab was discontinued and she was started on acyclovir, 800 mg five times daily for 2 weeks. She made a good recovery with improvement in her skin within 48 hours.She continued for 2 months on a prophylactic dose of 400 mg bd. Her rheumatoid arthritis became increasingly active and a decision was made to introduce adalimumab alongside acyclovir. Acyclovir prophylaxis has been continued but the dose tapered so that she is taking only 200 mg of acyclovir on alternate days. There has been no recurrence of Herpes Simplex Virus lesions despite increasing adalimumab to 40 mg weekly 3 months after starting treatment.ConclusionWe believe this to be the first reported case of widespread cutaneous Herpes Simplex Virus type 1 infection following treatment with infliximab. We discuss the clinical manifestations of Herpes Simplex Virus infections with particular emphasis on the immunosuppressed patient and the use of prophylactic acyclovir. Pustular psoriasis is now a well recognised but uncommon side effect of antitumour necrosis factor therapy and can lead to cessation of therapy, as in our patient's case.

The Herpes Simplex Virus Type 1 BgKLVariant, Unlike the BgOLVariant, Shows a Higher Association with Orolabial Infection than with Infections at Other Sites, Supporting the Variant-Dispersion-Replacement Hypothesis

The identification and geographic distribution of the herpes simplex virus type 1 (HSV-1) BglII restriction fragment length polymorphism (RFLP) variants named BgK(L) and BgO(L) in clinical isolates from orolabial and cutaneous sites were described in our previous reports, in which the dispersion and replacement of HSV-1 variants were proposed. The base substitution sites deduced from the BgK(L) multiple RFLP variations were mapped to the U(L)12 (DNase), R(L)2 (alpha0 transactivator), and latency-associated transcript genes in the present study. The results show that the relative frequencies (RFs) of BgK(L) are significantly higher in orolabial and cutaneous HSV-1 infections than in ocular infections. For the BgO(L) variant, the opposite was found; i.e., the RF of BgO(L) was significantly lower in orolabial and cutaneous infections than in ocular infections. No significant differences in the RFs of non-BgK(L):non-BgO(L) isolates were observed. The ratio of the BgK(L) RF to the BgO(L) RF was much higher for the orolabial and cutaneous infection groups than for the ocular infection group, whereas the BgK(L) RF-to-non-BgK(L):non-BgO(L) RF ratios for the former groups were slightly higher than those for the latter group. The higher efficiency of orolabial and cutaneous infections caused by BgK(L) compared to the efficiency of infections caused by BgO(L) allows BgK(L) to spread more efficiently in human populations and to displace BgO(L), because the mouth and lips are the most common HSV-1 infection sites in children. The present study supports our HSV-1 dispersion-and-replacement hypothesis and suggests that HSV-1, the latency-reactivation of which allows variants to accumulate in human populations, has evolved under competitive conditions, providing a new perspective on the polymorphism or variation of HSV-1.

The anti-viral effect of &lt;i&gt;Acacia mellifera, Melia azedarach&lt;/i&gt; and &lt;i&gt;Prunus Africana&lt;/i&gt;, extracts against herpes simplex virus type 1 infection in mice

Aqueous extracts from the stem barks of Prunus africana (Hook.f.) Kalkm, Acacia mellifera (Vahl.) Benth. and Melia azedarach L. were evaluated for in vivo antiviral activity in Balb/C mice following a cutaneous wild type strain 7401H herpes simplex virus type 1 (HSV-1) infection. A significant therapeutic effect was observed when the infected mice were orally treated with the extracts of Prunus africana and Acacia mellifera at a dose of 500 mg/kg. A delayed onset of skin lesions, slowed progression of infection and a prolonged mean survival time was expressed as opposed to the untreated infected control (p ≤0.05). Treatment with the Melia azedarach extract at a dose of 500 mg/kg was acutely toxic to mice, however a reasonable antiviral activity was exhibited at a lower dose of 250 mg/kg. No acute toxicity was presented in mice treated with P. africana and A. mellifera at the therapeutic dose. The results suggest the presence of anti-HSV agents in these medicinal plant extracts that can be exploited as possible antivirals. Keywords : Prunus africana, Acacia mellifera, Melia azedarach , HSV-1, antiviral activity, medicinal plants Journal of Tropical Microbiology and Biotechnology Vol. 2(1) 2006: 3-9

Herpes Simplex Virus Encephalitis During Suppressive Therapy With Acyclovir in a Premature Infant

Cutaneous herpes simplex virus type 2 (HSV-2) infection was recognized at 19 days of age in a 1415-g female infant born at 31 weeks of gestation. Cerebrospinal fluid (CSF) HSV polymerase chain reaction (PCR) was negative, and MRI of the brain was normal. After a 14-day course of high-dose intravenous acyclovir, the infant developed a cutaneous recurrence at 38 days of age. CSF HSV PCR again was negative. She was subsequently begun on oral acyclovir to prevent cutaneous reactivation of HSV. At 3 months of age, the infant developed HSV encephalitis as manifested by fever, seizures, abnormal CSF indices, abnormal brain MRI, and positive CSF HSV PCR. No cutaneous disease was present. It is not known whether the HSV encephalitis in our patient represented reactivation of previously unrecognized central nervous system infection or new onset of central nervous system disease as a result of spread from other tissue or site to the brain. The failure of oral acyclovir to prevent such an occurrence, however, highlights gaps in our understanding of the pathogenesis of neonatal HSV disease and questions the use of acyclovir suppression to prevent neurologic sequelae.

Extensive primary cutaneous herpes simplex virus type 1 infection in an infant following acute rotavirus gastroenteritis

Extensive primary cutaneous herpes simplex virus type 1 infection in an infant following acute rotavirus gastroenteritis

The early expression of glycoprotein B from herpes simplex virus can be detected by antigen-specific CD8+ T cells.

The immune response to cutaneous herpes simplex virus type 1 (HSV-1) infection begins with remarkable rapidity. Activation of specific cytotoxic T lymphocytes (CTL) begins within hours of infection, even though the response within the draining lymph nodes peaks nearly 5 days later. HSV gene products are classified into three main groups, alpha, beta, and gamma, based on their kinetics and requirements for expression. In C57BL/6 mice, the immunodominant epitope from HSV is derived from glycoprotein B (gB(498-505)). While gB is considered a gamma or "late" gene product, previous reports have indicated that some level of gene expression may occur soon after infection. Using brefeldin A as a specific inhibitor of viral antigen presentation to major histocompatibility complex class I-restricted CTL, we have formally addressed the timing of gB peptide expression in an immunologically relevant manner following infection. Presentation of gB peptide detected by T-cell activation was first observed within 2 h of infection. Comparison with another viral epitope expressed early during infection, HSV-1 ribonucleotide reductase, demonstrated that gB is presented with the same kinetics as this classical early-gene product. Moreover, this rapidity of gB expression was further illustrated via rapid priming of naïve transgenic CD8(+) T cells in vivo after HSV-1 infection of mice. These results establish that gB is expressed rapidly following HSV-1 infection, at levels capable of effectively stimulating CD8(+) T cells.

Rapid cytotoxic T lymphocyte activation occurs in the draining lymph nodes after cutaneous herpes simplex virus infection as a result of early antigen presentation and not the presence of virus.

Localized cutaneous herpes simplex virus type 1 (HSV-1) infection leads to arming and initial expansion of cytotoxic T lymphocytes (CTLs) in the draining popliteal lymph nodes (PLNs) followed by migration and further proliferation in the spleen. To accurately characterize the sequence of events involved in the activation and generation of anti-HSV CTLs, we used T cell receptor (TCR) transgenic mice specific for the immunodominant epitope from HSV glycoprotein B (gB498–505). We describe the detection of the initiation of antigen presentation in the draining lymph nodes by 4–6 h after infection with HSV-1. Analysis of CD69 up-regulation revealed activation of gB-specific CD8+ T cells by 6–8 h after infection. Furthermore, we show that T cell proliferation begins no sooner than 24 h after activation and is marked by the concurrent appearance of CTL activity in the PLNs. These events are not dependent on the presence of virus in the draining lymph nodes, and suggest a requirement for recruitment of professional antigen-presenting cells to the site of T cell activation. Consequently, we have defined the initiation of the CD8+ T cell–mediated response to cutaneous HSV-1 infection, demonstrating that the immune response to localized viral infection depends only on the appearance of cells presenting virus-derived antigen and commences with remarkable swiftness.

Efficacies of topical formulations of foscarnet and acyclovir and of 5-percent acyclovir ointment (Zovirax) in a murine model of cutaneous herpes simplex virus type 1 infection.

The topical efficacies of foscarnet and acyclovir incorporated into a polyoxypropylene-polyoxyethylene polymer were evaluated and compared to that of 5% acyclovir ointment (Zovirax) by use of a murine model of cutaneous herpes simplex virus type 1 infection. All three treatments given three times daily for 4 days and initiated 24 h after infection prevented the development of the zosteriform rash in mice. The acyclovir formulation and the acyclovir ointment reduced the virus titers below detectable levels in skin samples from the majority of mice, whereas the foscarnet formulation has less of an antiviral effect. Reducing the number of treatments to a single application given 24 h postinfection resulted in a significantly higher efficacy of the formulation of acyclovir than of the acyclovir ointment. Acyclovir incorporated within the polymer was also significantly more effective than the acyclovir ointment when treatment was initiated on day 5 postinfection. The higher efficacy of the acyclovir formulation than of the acyclovir ointment is attributed to the semiviscous character of the polymer, which allows better penetration of the drug into the skin.

Phenotypic Identification of Antigen-Dependent and Antigen-Independent CD8 CTL Precursors in the Draining Lymph Node During Acute Cutaneous Herpes Simplex Virus Type 1 Infection

Optimal immunological control of cutaneous herpes simplex virus type 1 (HSV-1) infections initiated in the hind footpad of C57BL/6 (B6, H-2b) mice is dependent upon the presence of functional HSV-1-specific T lymphocytes. The class I MHC-restricted, CD8+ T cell subpopulation is involved in the clearance of infectious HSV-1 from the skin and limiting HSV-1 replication and spread within the peripheral nervous system. However, the frequency of HSV-1-specific CTL precursors (CTLp), as a measure of potential anti-viral CD8+ T cell function, is relatively low compared with other acute viral infections. To gain insight into the basis for this low functional frequency, changes in the CD8+ T cell subpopulation phenotype associated with activation and differentiation were investigated. Analysis of the phenotypic changes showed that HSV-1-specific CTLp were found predominantly within a subpopulation of CD8+ T cells expressing high levels of CD44 (CD44high) and high levels of the IL-2 receptor alpha-chain (CD25high). A second activated subpopulation of CD8+ T cells expressing the CD44high CD25low phenotype did not contain detectable HSV-1-specific CTLp, even after the addition of HSV-1-infected stimulator cells as a source of an exogenous Ag. These data suggested that HSV-1-specific CD8+ T cells must increase expression of CD25 before attaining the potential to become CTL effector cells. These findings also indicated that the up-regulation of CD44 alone is not sufficient to identify precisely HSV-1-specific CD8+ T cells.

Evaluation of anti-herpesvirus activity of (1′ S,2′ R)-9-[[1′,2′-bis(hydroxymethyl)cycloprop-1′-yl]methyl]guanine (A-5021) in mice

The anti-herpesvirus activity of (1′ S,2′ R)-9-[[1′,2′-bis(hydroxymethyl)cycloprop-1′-yl]methyl]guanine (A-5021) was evaluated in murine cells and in several murine models of herpes simplex virus (HSV) infection. Against HSV type 1 (HSV-1), A-5021 was 15–30- and 30–60-fold more active, and against HSV type 2 (HSV-2), it was 2- and 8-fold more active than acyclovir and penciclovir in Balb/3T3 cells, respectively. When antiviral compounds were administered orally (once daily) to mice infected intraperitoneally with HSV-1 (Tomioka), A-5021 was more active than acyclovir or famciclovir in spite of its relatively low oral bioavailability. A-5021 was as active as penciclovir when the antiviral compounds were given intravenously (three times daily) to mice infected intraperitoneally with HSV-2 (186). In mice with a cutaneous HSV-1 (KOS) infection, three times daily oral therapy with A-5021 at 25 mg/kg per day produced more significant reduction in severity of skin lesions than equivalent treatment with acyclovir or famciclovir. In mice infected intracerebrally with HSV-1 (Tomioka), complete survival was observed in the group treated intravenously with A-5021 at 25 mg/kg per day (three times daily), while more than 50% of mice died in the groups treated intravenously with acyclovir of up to 100 mg/kg per day (three times daily). Moreover, A-5021 was more effective than acyclovir in clearing infectious virus from the brain. These findings demonstrate that A-5021 has potent anti-HSV activity in several murine models.