Targeted antiviral treatment using non-ionizing radiation therapy for SARS-CoV-2 and viral pandemics preparedness: Technique, methods and practical notes for clinical application.

OBJECTIVE: Pandemic outbreaks necessitate effective responses to rapidly mitigate and control the spread of disease and eliminate the causative organism(s). While conventional chemical and biological solutions to these challenges are characteristically slow to develop and reach public availability; recent advances in device components operating at Super High Frequency (SHF) bands (3-30 GHz) of the electromagnetic spectrum enable novel approaches to such problems. METHODS: Based on experimentally documented evidence, a clinically relevant in situ radiation procedure to reduce viral loads in patients is devised and presented. Adapted to the currently available medical device technology to cause viral membrane fracture, this procedure selectively inactivates virus particles by forced oscillations arising from Structure Resonant Energy Transfer (SRET) thereby reducing infectivity and disease progression. RESULTS: Effective resonant frequencies for pleiomorphic Coronavirus SARS-CoV-2 is calculated to be in the 10-17 GHz range. Using the relation y = -3.308x + 42.9 with x and y representing log10 number of virus particles and the clinical throat swab Ct value respectively; in situ patient-specific exposure duration of ~15x minutes can be utilized to inactivate up to 100% of virus particles in the throat-lung lining, using an irradiation dose of 14.5 ± 1 W/m2; which is within the 200 W/m2 safety standard stipulated by the International Commission on Non-Ionizing Radiation Protection (ICNIRP). CONCLUSIONS: The treatment is designed to make patients less contagious enhancing faster recoveries and enabling timely control of a spreading pandemic. ADVANCES IN KNOWLEDGE: The article provides practically applicable parameters for effective clinical adaptation of this technique to the current pandemic at different levels of healthcare infrastructure and disease prevention besides enabling rapid future viral pandemics response.

SARS-CoV-2 Survival on Surfaces and the Effect of UV-C Light.

The aim of this study was to establish the persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on inanimate surfaces such as plastic, stainless steel, and glass during UV-C irradiation which is a physical means commonly utilized in sanitization procedures. The viral inactivation rate, virus half-life, and percentage of titer reduction after UV-C irradiation were assessed. Infectivity was maintained on plastic and glass until 120 h and on stainless steel until 72 h. The virus half-life was 5.3, 4.4, and 4.2 h on plastic, stainless steel, and glass, respectively. In all cases, titer decay was >99% after drop drying. UV-C irradiation efficiently reduced virus titer (99.99%), with doses ranging from 10.25 to 23.71 mJ/cm2. Plastic and stainless steel needed higher doses to achieve target reduction. The total inactivation of SARS-CoV-2 on glass was obtained with the lower dose applied. SARS-CoV-2 survival can be long lasting on inanimate surfaces. It is worth recommending efficient disinfection protocols as a measure of prevention of viral spread. UV-C can provide rapid, efficient and sustainable sanitization procedures of different materials and surfaces. The dosages and mode of irradiation are important parameters to consider in their implementation as an important means to fight the SARS-CoV-2 pandemic.

Low Doses of Radiation Increase the Immunosuppressive Profile of Lung Macrophages During Viral Infection and Pneumonia.

PURPOSE: Severe pneumonia and acute respiratory distress syndrome (ARDS) have been described in patients with severe coronavirus disease 2019 (COVID-19). Recently, early clinical data reported the feasibility of low doses of radiation therapy (RT) in the treatment of ARDS in patients with severe COVID-19. However, the involved mechanisms remained unknown. METHODS AND MATERIALS: Here, we used airways-instilled lipopolysaccharide (LPS) and influenza virus (H1N1) as murine models of pneumonia, and toll-like receptor (TLR)-3 stimulation in human lung macrophages. RESULTS: Low doses of RT (0.5-1 Gray) decreased LPS-induced pneumonia, and increased the percentage of nerve- and airway-associated macrophages producing interleukin (IL) 10. During H1N1 viral infection, we observed decreased lung tissue damage and immune cell infiltration in irradiated animals. Low doses of RT increased IL-10 production by infiltrating immune cells into the lung. Irradiation of TLR-3 ligand-stimulated human lung macrophages ex vivo increased IL-10 secretion and decreased interferon γ production in the culture supernatant. The percentage of human lung macrophages producing IL-6 was also decreased. CONCLUSIONS: Our data highlight a mechanism by which low doses of RT regulate lung inflammation and skew lung macrophages toward an anti-inflammatory profile. These data provide a preclinical mechanistic support to clinical trials evaluating low doses of RT, such as COVID-19-induced ARDS.

Application of a Photocatalyst as an Inactivator of Bovine Coronavirus.

Bovine coronavirus (BCoV), a major causative pathogen of bovine enteric and respiratory diseases and a zoonotic pathogen transmissible between animals and humans, has led to severe economic losses in numerous countries. BCoV belongs to the genus Betacoronavirus, which is a model of a pathogen that is threatening human health and includes severe acute respiratory syndrome coronavirus (SARS-CoV), SARS-CoV-2, and Middle East respiratory syndrome coronavirus. This study aimed to determine whether photocatalytic material effectively reduces CoVs in the environment. Using the film adhesion method of photocatalytic materials, we assessed its antiviral activity and the effect of visible light irradiation according to methods defined by the International Organization for Standardization. Consequently, photocatalytic material was found to have antiviral activity, reducing the viral loads by 2.7 log TCID50 (tissue culture infective dose 50)/0.1 mL (500 lux), 2.8 log TCID50/0.1 mL (1000 lux), and 2.4 log TCID50/0.1 mL (3000 lux). Hence, this photocatalytic material might be applicable not only to reducing CoVs in the cattle breeding environment but also perhaps in other indoor spaces, such as offices and hospital rooms. To our knowledge, this study is the first to evaluate the antiviral activity of a photocatalytic material against CoV.

5-aminolevulinic acid photodynamic therapy reduces HPV viral load via autophagy and apoptosis by modulating Ras/Raf/MEK/ERK and PI3K/AKT pathways in HeLa cells.

Human papillomavirus (HPV) infection is linked to several diseases, the most prominent of which are cervical cancer and genital condyloma acuminatum. Previous studies have suggested an effective role for 5-aminolevulinic acid photodynamic therapy (ALA-PDT) against various cancers by the induction of autophagy and apoptosis. However, few reports have focused on the effectiveness of ALA-PDT on HPV related disorders. To identify the role of ALA-PDT in the context of HPV infection, we initially investigated 111 patients suffering from genital condyloma acuminatum. HPV viral load detected before and after ALA-PDT treatment was compared during this procedure; a significant difference was noted. HeLa (HPV18) cells were exposed to ALA-PDT in vitro to further explore the underlying mechanisms. Western blot analysis showed that ALA-PDT induces LC3II and p62 expression, along with the up regulation of caspase-3 and cleaved caspase-3. Our study also demonstrated that ALA-PDT treatment inhibits the proliferation of HeLa cells in a dose dependent manner and effectively reduces HPV viral load via autophagy and apoptosis by regulating the Ras/Raf/MEK/ERK and PI3K/AKT/mTOR pathways. Hydroxychloroquine (HCQ), although it inhibited autophagy degradation, functioned to activate reactive oxygen species (ROS) levels of ALA-PDT to enhance the observed effect. These findings suggest strategies for the improvement of PDT efficacy in patients.

A novel human in vitro papillomavirus type 16 positive tonsil cancer cell line with high sensitivity to radiation and cisplatin.

BACKGROUND: Human papillomavirus (HPV) is an established risk factor for oropharyngeal squamous cell carcinoma (OSCC). The aim was to establish cell lines from HPV-positive tonsil carcinomas to be used for treatment development. METHODS: Fresh samples from 23 HPV-positive tonsil carcinomas were cultivated in vitro. The established cell line was analyzed for viral characteristics, cell karyotype, TP53 status, and growth capabilities in nude mice. In vitro studies of sensitivities to radiation, cisplatin and cetuximab were performed. RESULTS: After 19 months (eight passages), one cell line, LU-HNSCC-26, was established in vitro and also grew as xenografts. The tumor was from a 48 year old non-smoking man with non-keratinizing, p16 positive tonsil OSCC, stage T2N0M0 with HPV16. It contained 19.5 (CV% 3.7) HPV16 copies/cell (passage 8). The complete HPV16 genome sequence was obtained. Episomal HPV16 was present with an E2/E7 ratio of 1.1 (CV% 2.6). In addition, HPV16 mRNA specific for the intact E2 gene was detected. The viral expression manifested 1.0 (CV% 0.1) E7 mRNA copies per HPV16 genome. The karyotype was determined and the cell line demonstrated wild type TP53. The ID50 for radiation was 0.90 Gy and the IC50 for cisplatin was 0.99 µmol/L. The cell line was inhibited to a maximum of 18% by cetuximab. CONCLUSIONS: We established an in vitro tonsil carcinoma cell line containing episomal HPV16. This is an important step towards efficient treatment development.

Reactivation of Latent Epstein-Barr Virus: A Comparison after Exposure to Gamma, Proton, Carbon, and Iron Radiation.

Among the many stressors astronauts are exposed to during spaceflight, cosmic radiation may lead to various serious health effects. Specifically, space radiation may contribute to decreased immunity, which has been documented in astronauts during short- and long-duration missions, as evidenced by several changes in cellular immunity and plasma cytokine levels. Reactivation of latent herpes viruses, either directly from radiation of latently infected cells and/or from perturbation of the immune system, may result in disease in astronauts. Epstein‒Barr virus (EBV) is one of the eight human herpes viruses known to infect more than 90% of human adults and persists for the life of the host without normally causing adverse effects. Reactivation of several latent viruses in astronauts is well documented, although the mechanism of reactivation is not well understood. We studied the effect of four different types of radiation, (1) 137Cs gamma rays, (2) 150-MeV protons, (3) 600 MeV/n carbon ions, and (4) 600 MeV/n iron ions on the activation of lytic gene transcription and of reactivation of EBV in a latently infected cell line (Akata) at doses of 0.1, 0.5, 1.0, and 2.0 Gy. The data showed that for all doses used in this study, lytic gene transcription was induced and median viral loads were significantly higher for all types of radiation than in corresponding control samples, with the increases detected as early as four days post-exposure and generally tapering off at later time points. The viability and size of EBV-infected Akata cells were highly variable and exhibited approximately the same trend in time for all radiation types at 0.1, 0.5, 1.0, and 2.0 Gy. This work shows that reactivation of viruses can occur due to the effect of different types of radiation on latently infected cells in the absence of changes or cytokines produced in the immune system. In general, gamma rays are more effective than protons, carbon ions, and iron ions in inducing latent virus reactivation, though these high-energy particles did induce more sustained and later reactivation of EBV lytic gene transcription. These findings also challenge the common relative biological effectiveness concept that is often used in radiobiology for other end points.

Effect of cold atmospheric plasma (CAP) on human adenoviruses is adenovirus type-dependent.

More than 70 human adenovirus types were identified divided into 7 different species (A-G). Diseases caused by human adenoviruses are type-dependent and can range from mild to severe respiratory infections, gastrointestinal infections or eye infections such as epidemic keratoconjunctivitis. Unfortunately there is no specific anti-adenovirus therapy available. Here we addressed the question whether treatment with cold atmospheric plasma (CAP) for anti-adenoviral therapy such as virus-mediated ulcerations may be feasible. CAP has already been explored for the treatment of dermatological diseases such as chronic wounds. To investigate whether CAP is an effective antiviral tool, purified human adenovirus types derived from different human adenovirus species (HAdV -4, -5, -20, -35, -37, -50) tagged with luciferase were treated with defined dosages of plasma. The CAP treatment was varied by incrementally increasing the time span of CAP treatment. After CAP treatment, the virus containing solution was added to eukaryotic cells and the viral load was determined by measurement of luciferase expression levels. Through the plasma treatment the adenovirus driven luciferase expression directly correlating with adenovirus transduction efficiencies could be reduced for HAdV-5 and HAdV-37. Plasma treatment had no influence on adenovirus derived luciferase expression levels for HAdV-4 and HAdV-50 and it even had a positive effect on luciferase expression levels for HAdV-20 and HAdV-35. These results suggest that CAP has a type dependent effect on adenoviruses and that infectivity can be even increased for certain adenovirus types. Further studies should address the mechanisms behind this phenomenon. In summary we demonstrate that CAP may represent an interesting option for antiviral treatment in a virus type dependent manner.

Inactivation of Middle East respiratory syndrome-coronavirus in human plasma using amotosalen and ultraviolet A light.

BACKGROUND: Middle East respiratory syndrome-coronavirus (MERS-CoV) is a novel zoonotic pathogen. Although the potential for MERS-CoV transmission through blood transfusion is not clear, MERS-CoV was recognized as a pathogen of concern for the safety of the blood supply especially after its detection in whole blood, serum, and plasma of infected individuals. Here we investigated the efficacy of amotosalen and ultraviolet A light (UVA) to inactivate MERS-CoV in fresh-frozen plasma (FFP). STUDY DESIGN AND METHODS: Pooled FFP units were spiked with a recent clinical MERS-CoV isolate. Infectious and genomic viral titers were determined in plasma before and after inactivation with amotosalen/UVA treatment by plaque assay and reverse transcription-quantitative polymerase chain reaction, respectively. In addition, residual replicating or live virus after inactivation was examined by passaging in the permissive Vero E6 cells. RESULTS: The mean MERS-CoV infectious titer in pretreatment samples was 4.67 ± 0.25 log plaque-forming units (pfu)/mL, which was reduced to undetectable levels after inactivation with amotosalen/UVA demonstrating a mean log reduction of more than 4.67 ± 0.25 pfu/mL. Furthermore, inoculation of inactivated plasma on Vero E6 cells did not result in any cytopathic effect (CPE) even after 7 days of incubation and three consecutive passages, nor the detection of MERS RNA compared to pretreatment samples which showed complete CPE within 2 to 3 days postinoculation and log viral RNA titer ranging from 9.48 to 10.22 copies/mL in all three passages. CONCLUSION: Our data show that amotosalen/UVA treatment is a potent and effective way to inactivate MERS-CoV infectious particles in FFP to undetectable levels and to minimize the risk of any possible transfusion-related MERS-CoV transmission.

UV Disinfection of Wastewater and Combined Sewer Overflows.

Municipal wastewater contains bacteria, viruses, and other pathogens that adversely affect the environment, human health, and economic activity. One way to mitigate these effects is a final disinfection step using ultraviolet light (UVL). The advantages of UVL disinfection, when compared to the more traditional chlorine, include no chlorinated by-products, no chemical residual, and relatively compact size. The design of most UV reactors is complex. It involves lamp selection, power supply design, optics, and hydraulics. In general, medium pressure lamps are more compact, powerful, and emit over a wider range of light than the more traditional low pressure lamps. Low pressure lamps, however, may be electrically more efficient. In UV disinfection, the fraction of surviving organisms (e.g. E. coli) will decrease exponentially with increasing UV dose. However, the level of disinfection that can be achieved is often limited by particle-associated organisms. Efforts to remove or reduce the effects of wastewater particles will often improve UV disinfection effectiveness. Regrowth, photoreactivation, or dark repair after UV exposure are sometimes cited as disadvantages of UV disinfection. Research is continuing in this area, however there is little evidence that human pathogens can photoreactivate in environmental conditions, at doses used in wastewater treatment. The UV disinfection of combined sewer overflows, a form of wet weather pollution, is challenging and remains largely at the research phase. Pre-treatment of combined sewer overflows (CSOs) with a cationic polymer to induce fast settling, and a low dose of alum to increase UV transmittance, has shown promise at the bench scale.

Loss of immune homeostasis dictates SHIV rebound after stem-cell transplantation.

The conditioning regimen used as part of the Berlin patient's hematopoietic cell transplant likely contributed to his eradication of HIV infection. We studied the impact of conditioning in simian-human immunodeficiency virus-infected (SHIV-infected) macaques suppressed by combination antiretroviral therapy (cART). The conditioning regimen resulted in a dramatic, but incomplete depletion of CD4+ and CD8+ T cells and CD20+ B cells, increased T cell activation and exhaustion, and a significant loss of SHIV-specific Abs. The disrupted T cell homeostasis and markers of microbial translocation positively correlated with an increased viral rebound after cART interruption. Quantitative viral outgrowth and Tat/rev-induced limiting dilution assays showed that the size of the latent SHIV reservoir did not correlate with viral rebound. These findings identify perturbations of the immune system as a mechanism for the failure of autologous transplantation to eradicate HIV. Thus, transplantation strategies may be improved by incorporating immune modulators to prevent disrupted homeostasis, and gene therapy to protect transplanted cells.

The Paradoxical Effects of Different Hepatitis C Viral Loads on Host DNA Damage and Repair Abilities.

Hepatitis C virus (HCV)-induced hepatic stress is associated with increased oxidative DNA damage and has been implicated in hepatic inflammation. However, HCV infection and replication are uneven and vary among individual hepatocytes. To investigate the effect of the viral load on host DNA damage, we used an Enhanced Yellow Fluorescent Protein gene (EYFP)-tagged HCV virus to distinguish between HCV intracellular high viral load (HVL) cells and low viral load (LVL) cells. The cell sorting efficiency was confirmed by the high expression of the HCV polyprotein. We found DNA damage γ-H2AX foci in the HVL population. Comet assays demonstrated that HVL was related to the extent of the DNA strand breaks. Surprisingly, the DNA qPCR arrays and western blotting showed that the damage-related genes GPX2, MRE11, phospho-ATM, and OGG1 were significantly up-regulated in LVL cells but inversely down-regulated or consistently expressed in HVL cells. The colony survival assay to examine the repair abilities of these cells in response to irradiation showed that the LVL cells were more resistant to irradiation and had an increased ability to repair radiation-induced damage. This study found that intracellular viral loads drove cellular DNA damage levels but suppressed damage-related gene expression. However, the increase in damage-related gene expression in the LVL cells may be affected by ROS from the HVL cells. These findings provide new insights into the distinct DNA damage and repair responses resulting from different viral loads in HCV-infected cells.

Inactivation of Middle East respiratory syndrome coronavirus (MERS-CoV) in plasma products using a riboflavin-based and ultraviolet light-based photochemical treatment.

BACKGROUND: Middle East respiratory syndrome coronavirus (MERS-CoV) has been identified as a potential threat to the safety of blood products. The Mirasol Pathogen Reduction Technology System uses riboflavin and ultraviolet (UV) light to render blood-borne pathogens noninfectious while maintaining blood product quality. Here, we report on the efficacy of riboflavin and UV light against MERS-CoV when tested in human plasma. STUDY DESIGN AND METHODS: MERS-CoV (EMC strain) was used to inoculate plasma units that then underwent treatment with riboflavin and UV light. The infectious titers of MERS-CoV in the samples before and after treatment were determined by plaque assay on Vero cells. The treatments were initially performed in triplicate using pooled plasma (n = 3) and then repeated using individual plasma units (n = 6). RESULTS: In both studies, riboflavin and UV light reduced the infectious titer of MERS-CoV below the limit of detection. The mean log reductions in the viral titers were ≥4.07 and ≥4.42 for the pooled and individual donor plasma, respectively. CONCLUSION: Riboflavin and UV light effectively reduced the titer of MERS-CoV in human plasma products to below the limit of detection, suggesting that the treatment process may reduce the risk of transfusion transmission of MERS-CoV.

HSV-1 Infection Modulates the Radioresponse of a HPV16-positive Head and Neck Cancer Cell Line.

BACKGROUND: The combined effects of Human papillomavirus (HPV) and Herpes simplex type 1 (HSV-1) infections and their effects on cancer cell radioresistance are unexplored. MATERIALS AND METHODS: An HPV16-positive hypopharyngeal carcinoma cell line (UD-SCC-2) was infected with wt-HSV-1 at low multiplicity of infection (MOI) and irradiated with 2 Gy at 24 h postinfection. Viability assays and quantitative reverse-transcriptase PCR for HPV16 E6, E7, nuclear factor kappa B1, B-cell CLL/lymphoma 2 (BCL2), and caspases 3, 8 and 9 at 24, and 72 h, as well as immunocytochemistry for BCL2, caspase 3, cyclin E, mouse double minute 2 homolog (MDM2), HSV-1 and Ki-67 were performed at 144 h postirradiation. RESULTS: At 144 h, cell viability was significantly lowered by irradiation only in uninfected cells. Infection combined with irradiation resulted in increased expression of E6, E7, BCL2 and NF-κB1 at 144 h. Simultaneously, E6 and E7 were down-regulated in non-irradiated infected cells. Irradiation and infection with 0.00001 MOI separately up-regulated caspase 3 but infection with 0.0001 MOI halved its expression in irradiated cells. CONCLUSION: HSV-1 infection modulates radioresistance of HPV16-positive hypopharyngeal carcinoma cells.

Solar Disinfection of Viruses in Polyethylene Terephthalate Bottles.

Solar disinfection (SODIS) of drinking water in polyethylene terephthalate (PET) bottles is a simple, efficient point-of-use technique for the inactivation of many bacterial pathogens. In contrast, the efficiency of SODIS against viruses is not well known. In this work, we studied the inactivation of bacteriophages (MS2 and ϕX174) and human viruses (echovirus 11 and adenovirus type 2) by SODIS. We conducted experiments in PET bottles exposed to (simulated) sunlight at different temperatures (15, 22, 26, and 40°C) and in water sources of diverse compositions and origins (India and Switzerland). Good inactivation of MS2 (>6-log inactivation after exposure to a total fluence of 1.34 kJ/cm(2)) was achieved in Swiss tap water at 22°C, while less-efficient inactivation was observed in Indian waters and for echovirus (1.5-log inactivation at the same fluence). The DNA viruses studied, ϕX174 and adenovirus, were resistant to SODIS, and the inactivation observed was equivalent to that occurring in the dark. High temperatures enhanced MS2 inactivation substantially; at 40°C, 3-log inactivation was achieved in Swiss tap water after exposure to a fluence of only 0.18 kJ/cm(2). Overall, our findings demonstrate that SODIS may reduce the load of single-stranded RNA (ssRNA) viruses, such as echoviruses, particularly at high temperatures and in photoreactive matrices. In contrast, complementary measures may be needed to ensure efficient inactivation during SODIS of DNA viruses resistant to oxidation.

Trends in Prevalence of HIV-1 Drug Resistance in a Public Clinic in Maputo, Mozambique

Background: An observational study was conducted in Maputo, Mozambique, to investigate trends in prevalence of HIV drug resistance (HIVDR) in antiretroviral (ART) naïve subjects initiating highly active antiretroviral treatment (HAART). Methodology/principal findings: To evaluate the pattern of drug resistance mutations (DRMs) found in adults on ART failing first-line HAART [patients with detectable viral load (VL)]. Untreated subjects [Group 1 (G1; n=99)] and 274 treated subjects with variable length of exposure to ARV´s [6-12 months, Group 2 (G2;n=93); 12-24 months, Group 3 (G3;n=81); >24 months (G4;n=100)] were enrolled. Virological and immunological failure (VF and IF) were measured based on viral load (VL) and T lymphocyte CD4+ cells (TCD4+) count and genotypic resistance was also performed. Major subtype found was C (untreated: n=66, 97,06%; treated: n=36, 91.7%). Maximum virological suppression was observed in G3, and significant differences intragroup were observed between VF and IF in G4 (p=0.022). Intergroup differences were observed between G3 and G4 for VF (p=0.023) and IF between G2 and G4 (p=0.0018). Viral suppression (<50 copies/ml) ranged from 84.9% to 90.1%, and concordant VL and DRM ranged from 25% to 57%. WHO cut-off for determining VF as given by 2010 guidelines (>5000 copies/ml) identified 50% of subjects carrying DRM compared to 100% when lower VL cut-off was used (<50 copies/ml). Length of exposure to ARVs was directly proportional to the complexity of DRM patterns. In Mozambique, VL suppression was achieved in 76% of individuals after 24 months on HAART. This is in agreement with WHO target for HIVDR prevention target (70%). Conclusions: We demonstrated that the best way to determine therapeutic failure is VL compared to CD4 counts. The rationalized use of VL testing is needed to ensure timely detection of treatment failures preventing the occurrence of TDR and new infections.

Impact of irradiation and immunosuppressive agents on immune system homeostasis in rhesus macaques.

In this study we examined the effects of non-myeloablative total body irradiation (TBI) in combination with immunosuppressive chemotherapy on immune homeostasis in rhesus macaques. Our results show that the administration of cyclosporin A or tacrolimus without radiotherapy did not result in lymphopenia. The addition of TBI to the regimen resulted in lymphopenia as well as alterations in the memory/naive ratio following reconstitution of lymphocyte populations. Dendritic cell (DC) numbers in whole blood were largely unaffected, while the monocyte population was altered by immunosuppressive treatment. Irradiation also resulted in increased levels of circulating cytokines and chemokines that correlated with T cell proliferative bursts and with the shift towards memory T cells. We also report that anti-thymocyte globulin (ATG) treatment and CD3 immunotoxin administration resulted in a selective and rapid depletion of naive CD4 and CD8 T cells and increased frequency of memory T cells. We also examined the impact of these treatments on reactivation of latent simian varicella virus (SVV) infection as a model of varicella zoster virus (VZV) infection of humans. None of the treatments resulted in overt SVV reactivation; however, select animals had transient increases in SVV-specific T cell responses following immunosuppression, suggestive of subclinical reactivation. Overall, we provide detailed observations into immune modulation by TBI and chemotherapeutic agents in rhesus macaques, an important research model of human disease.

Effects of ocular surface strontium-90 beta radiotherapy in dogs latently infected with canine herpesvirus-1.

Latent canine herpesvirus-1 (CHV-1) infections are common in domestic dogs, but stimuli causing viral reactivation and recrudescent disease are poorly understood. Immunosuppressive pharmaceuticals are currently the only experimentally established triggers for recurrent ocular CHV-1 infection in dogs; however, ocular CHV-1 shedding has been reported clinically following strontium-90 beta radiotherapy of the ocular surface and it has been speculated that radiotherapy can directly induce viral reactivation. Strontium-90 is used as a beta radiation source for the treatment of a variety of neoplastic and immune-mediated canine ocular surface diseases. In the present study, the effects of ocular surface strontium-90 beta radiotherapy in dogs latently infected with CHV-1 were evaluated. Ten mature dogs with experimentally induced latent CHV-1 infections were randomly divided into two groups: one group received a single fraction 50 Gy radiation dose in one application from a strontium-90 ophthalmic applicator and the second group received sham radiotherapy. Dogs were then monitored for 45 days for recurrent ocular CHV-1 infection using clinical and virological outcome measures. Clinical ophthalmic examinations, ocular sample CHV-1 PCR assays, and serum CHV-1 virus neutralizing antibody assays were performed at specified intervals. No abnormalities suggestive of recurrent CHV-1 ocular disease were observed on clinical examination in any dog during the study. Ocular viral shedding was not detected and CHV-1 virus neutralizing titers remained stable in all dogs. A single fraction 50 Gy radiation dose administered to the ocular surface by strontium-90 beta radiotherapy did not result in detectable recurrent ocular CHV-1 infection in mature dogs with experimentally induced latent infection.