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Hahn MM, Triplett CA, Anderson MS, Smart JI, Litherland K, Keech S, von Siebenthal F, Jones M, Phipps AJ, Henning LN. Ceftobiprole Medocaril Is an Effective Post-Exposure Treatment in the Fischer 344 Rat Model of Pneumonic Tularemia. Antibiotics (Basel) 2023; 12:1337. [PMID: 37627757 PMCID: PMC10451734 DOI: 10.3390/antibiotics12081337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/19/2023] [Accepted: 08/16/2023] [Indexed: 08/27/2023] Open
Abstract
Francisella tularensis subspecies tularensis is a category-A biothreat agent that can cause lethal tularemia. Ceftobiprole medocaril is being explored as a medical countermeasure for the treatment of pneumonic tularemia. The efficacy of ceftobiprole medocaril against inhalational tularemia was evaluated in the Fischer 344 rat model of infection. The dose was expected to be effective against F. tularensis isolates with ceftobiprole minimum inhibitory concentrations ≤0.5 µg/mL. Animals treated with ceftobiprole medocaril exhibited a 92% survival rate 31 days post-challenge, identical to the survival of levofloxacin-treated rats. By comparison, rats receiving placebo experienced 100% mortality. Terminally collected blood, liver, lung, and spleen samples confirmed disseminated F. tularensis infections in most animals that died prior to completing treatments (placebo animals and a rat treated with ceftobiprole medocaril), although levels of bacteria detected in the placebo samples were significantly elevated compared to the ceftobiprole-medocaril-treated group geometric mean. Furthermore, no evidence of infection was detected in any rat that completed ceftobiprole medocaril or levofloxacin treatment and survived to the end of the post-treatment observation period. Overall, survival rates, body weights, and bacterial burdens consistently demonstrated that treatment with ceftobiprole medocaril is efficacious against otherwise fatal cases of pneumonic tularemia in the rat model.
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Affiliation(s)
| | | | | | - Jennifer I. Smart
- Basilea Pharmaceutica International Ltd., 4123 Allschwil, Switzerland
| | - Karine Litherland
- Basilea Pharmaceutica International Ltd., 4123 Allschwil, Switzerland
| | - Stephen Keech
- Basilea Pharmaceutica International Ltd., 4123 Allschwil, Switzerland
| | | | - Mark Jones
- Basilea Pharmaceutica International Ltd., 4123 Allschwil, Switzerland
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2
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Chuang YF, Phipps AJ, Lin FL, Hecht V, Hewitt AW, Wang PY, Liu GS. Approach for in vivo delivery of CRISPR/Cas system: a recent update and future prospect. Cell Mol Life Sci 2021; 78:2683-2708. [PMID: 33388855 PMCID: PMC11072787 DOI: 10.1007/s00018-020-03725-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Revised: 11/19/2020] [Accepted: 11/26/2020] [Indexed: 12/14/2022]
Abstract
The clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated (Cas) system provides a groundbreaking genetic technology that allows scientists to modify genes by targeting specific genomic sites. Due to the relative simplicity and versatility of the CRISPR/Cas system, it has been extensively applied in human genetic research as well as in agricultural applications, such as improving crops. Since the gene editing activity of the CRISPR/Cas system largely depends on the efficiency of introducing the system into cells or tissues, an efficient and specific delivery system is critical for applying CRISPR/Cas technology. However, there are still some hurdles remaining for the translatability of CRISPR/Cas system. In this review, we summarized the approaches used for the delivery of the CRISPR/Cas system in mammals, plants, and aquacultures. We further discussed the aspects of delivery that can be improved to elevate the potential for CRISPR/Cas translatability.
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Affiliation(s)
- Yu-Fan Chuang
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Avenue, Shenzhen University Town, Shenzhen, 518055, China
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS, 7000, Australia
| | - Andrew J Phipps
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Fan-Li Lin
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Avenue, Shenzhen University Town, Shenzhen, 518055, China
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS, 7000, Australia
| | - Valerie Hecht
- School of Natural Sciences, University of Tasmania, Hobart, TAS, Australia
| | - Alex W Hewitt
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS, 7000, Australia
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, VIC, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia
| | - Peng-Yuan Wang
- Shenzhen Key Laboratory of Biomimetic Materials and Cellular Immunomodulation, Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, 1068 Xueyuan Avenue, Shenzhen University Town, Shenzhen, 518055, China.
- Department of Chemistry and Biotechnology, Swinburne University of Technology, Hawthorn, VIC, Australia.
| | - Guei-Sheung Liu
- Menzies Institute for Medical Research, University of Tasmania, 17 Liverpool Street, Hobart, TAS, 7000, Australia.
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC, Australia.
- Aier Eye Institute, Changsha, Hunan, China.
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3
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Dyer M, Phipps AJ, Mitew S, Taberlay PC, Woodhouse A. Age, but Not Amyloidosis, Induced Changes in Global Levels of Histone Modifications in Susceptible and Disease-Resistant Neurons in Alzheimer's Disease Model Mice. Front Aging Neurosci 2019; 11:68. [PMID: 31001106 PMCID: PMC6456813 DOI: 10.3389/fnagi.2019.00068] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2018] [Accepted: 03/11/2019] [Indexed: 12/23/2022] Open
Abstract
There is increasing interest in the role of epigenetic alterations in Alzheimer’s disease (AD). The epigenome of every cell type is distinct, yet data regarding epigenetic change in specific cell types in aging and AD is limited. We investigated histone tail modifications in neuronal subtypes in wild-type and APP/PS1 mice at 3 (pre-pathology), 6 (pathology-onset) and 12 (pathology-rich) months of age. In neurofilament (NF)-positive pyramidal neurons (vulnerable to AD pathology), and in calretinin-labeled interneurons (resistant to AD pathology) there were no global alterations in histone 3 lysine 4 trimethylation (H3K4me3), histone 3 lysine 27 acetylation (H3K27ac) or histone 3 lysine 27 trimethylation (H3K27me3) in APP/PS1 compared to wild-type mice at any age. Interestingly, age-related changes in the presence of H3K27ac and H3K27me3 were detected in NF-labeled pyramidal neurons and calretinin-positive interneurons, respectively. These data suggest that the global levels of histone modifications change with age, whilst amyloid plaque deposition and its sequelae do not result in global alterations of H3K4me3, H3K27ac and H3K27me3 in NF-positive pyramidal neurons or calretinin-labeled interneurons.
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Affiliation(s)
- Marcus Dyer
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia.,Menzies Institute for Medical Research, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Andrew J Phipps
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Stanislaw Mitew
- Duke-NUS Medical School, National University of Singapore, Singapore, Singapore
| | - Phillippa C Taberlay
- School of Medicine, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Adele Woodhouse
- Wicking Dementia Research and Education Centre, College of Health and Medicine, University of Tasmania, Hobart, TAS, Australia
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Phipps AJ, Beggs DS, Murray AJ, Mansell PD, Pyman MF. A survey of northern Victorian dairy farmers to investigate dairy calf management: calf-rearing practices. Aust Vet J 2018; 96:107-110. [PMID: 29577252 DOI: 10.1111/avj.12686] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/17/2017] [Indexed: 12/01/2022]
Abstract
OBJECTIVES To describe the calf-rearing practices carried out in northern Victorian dairy herds and to identify weaknesses that may affect calf health and welfare by comparing the results with current industry recommendations. METHODS Survey of dairy farms from Rochester and the surrounding farming area. RESULTS The response rate was 39% (58/150). Many dairy producers were not meeting the current industry recommendations in the following areas: (1) delayed access to pellets and roughage, (2) failing to provide access to water from birth, (3) delayed disbudding of calves, (4) delayed timing of booster vaccinations, (5) weaning based on age alone, (6) failing to isolate sick calves and (7) early sale age of excess calves. CONCLUSION The results from this survey highlight the need for greater awareness of industry standards for calf husbandry and weaning.
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Affiliation(s)
- A J Phipps
- Rochester Veterinary Practice, Rochester, Victoria, Australia.,Faculty of Veterinary and Agricultural Science, The University of Melbourne, Werribee, Victoria, Australia
| | - D S Beggs
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Werribee, Victoria, Australia
| | - A J Murray
- Rochester Veterinary Practice, Rochester, Victoria, Australia
| | - P D Mansell
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Werribee, Victoria, Australia
| | - M F Pyman
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Werribee, Victoria, Australia
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Phipps AJ, Beggs DS, Murray AJ, Mansell PD, Pyman MF. A survey of northern Victorian dairy farmers to investigate dairy calf management: colostrum feeding and management. Aust Vet J 2018; 96:101-106. [PMID: 29577249 PMCID: PMC7159743 DOI: 10.1111/avj.12683] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2016] [Revised: 07/11/2017] [Accepted: 07/18/2017] [Indexed: 11/28/2022]
Abstract
Objectives To describe colostrum management practices carried out in northern Victorian dairy herds and to identify weaknesses in these areas that may affect calf health and welfare by comparing the results with the current industry recommendations Methods A questionnaire to obtain information about colostrum management and calf‐rearing practices was sent to commercial dairy farming clients of Rochester Veterinary Practice between June and September 2013. The questionnaire consisted of a general herd overview and colostrum harvesting practices. Results The response rate was 39% (58/150). Many dairy producers were not meeting the current industry recommendations in the following areas: (1) time of removal calf from the dam, (2) relying on calf suckling colostrum from the dam to achieve adequate passive transfer, (3) failing to supplement calves with colostrum, (4) feeding inadequate volumes of colostrum, (5) delayed colostrum harvesting, (6) pooling of colostrum, (7) failing to objectively assess colostrum quality or relying on visual assessment and (8) storing colostrum for a prolonged periods of time at ambient temperatures. Conclusion The results from this survey highlight the need for greater awareness of industry standards for colostrum management and feeding hygiene.
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Affiliation(s)
- A J Phipps
- Rochester Veterinary Practice, Rochester, Victoria, Australia.,Faculty of Veterinary and Agricultural Science, The University of Melbourne, Werribee, Victoria, Australia
| | - D S Beggs
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Werribee, Victoria, Australia
| | - A J Murray
- Rochester Veterinary Practice, Rochester, Victoria, Australia
| | - P D Mansell
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Werribee, Victoria, Australia
| | - M F Pyman
- Faculty of Veterinary and Agricultural Science, The University of Melbourne, Werribee, Victoria, Australia
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6
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Phipps AJ, Beggs DS, Murray AJ, Mansell PD, Pyman MF. Factors associated with colostrum immunoglobulin G concentration in northern-Victorian dairy cows. Aust Vet J 2017; 95:237-243. [PMID: 28653388 DOI: 10.1111/avj.12601] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 09/19/2016] [Accepted: 10/12/2016] [Indexed: 11/30/2022]
Abstract
OBJECTIVES To determine the proportion of first-milking colostrum samples produced on four northern-Victorian dairy farms that meet industry standards in terms of immunoglobulin G (IgG) concentration and to identify risk factors that affect colostrum quality. METHODS Colostrum IgG concentrations from 442 dairy cows on four farms were estimated using a Brix refractometer and risk factors for colostrum IgG concentration were determined using multivariable logistic regression. RESULTS Only 39% of samples met the definition of high quality. The strongest predictor for colostrum quality was the interval from calving to colostrum harvesting. Colostrum harvested from cows within 12 h of calving was 6-fold more likely to be high quality compared with colostrum harvested later. Colostrum from cows in ≥ 4th lactation was nearly twice as likely to be high quality compared with cows entering their 1st lactation. If the calf was not allowed to suckle from the dam prior to colostrum harvesting, the odds of producing high-quality colostrum were nearly 4-fold greater. If the cow had not leaked colostrum prior to harvesting, it was more than 3-fold more likely to produce high-quality colostrum. CONCLUSIONS The majority of samples assessed were below industry standard. Herd, lactation number, calf suckling or cow leaking colostrum prior to harvesting and time between calving and colostrum harvesting were factors that influenced colostrum IgG concentration. The results support current industry recommendations of harvesting colostrum shortly after parturition (ideally within 12 h of calving) and testing the quality of all colostrum prior to feeding to dairy calves.
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Affiliation(s)
- A J Phipps
- Rochester Veterinary Practice, 72 Lowry Street, Rochester, Victoria 3561, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - D S Beggs
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - A J Murray
- Rochester Veterinary Practice, 72 Lowry Street, Rochester, Victoria 3561, Australia
| | - P D Mansell
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
| | - M F Pyman
- Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Werribee, Victoria, Australia
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Li ZN, Weber KM, Limmer RA, Horne BJ, Stevens J, Schwerzmann J, Wrammert J, McCausland M, Phipps AJ, Hancock K, Jernigan DB, Levine M, Katz JM, Miller JD. Evaluation of multiplex assay platforms for detection of influenza hemagglutinin subtype specific antibody responses. J Virol Methods 2017; 243:61-67. [PMID: 28108183 DOI: 10.1016/j.jviromet.2017.01.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 01/11/2017] [Accepted: 01/12/2017] [Indexed: 11/26/2022]
Abstract
Influenza hemagglutination inhibition (HI) and virus microneutralization assays (MN) are widely used for seroprevalence studies. However, these assays have limited field portability and are difficult to fully automate for high throughput laboratory testing. To address these issues, three multiplex influenza subtype-specific antibody detection assays were developed using recombinant hemagglutinin antigens in combination with Chembio, Luminex®, and ForteBio® platforms. Assay sensitivity, specificity, and subtype cross-reactivity were evaluated using a panel of well characterized human sera. Compared to the traditional HI, assay sensitivity ranged from 87% to 92% and assay specificity in sera collected from unexposed persons ranged from 65% to 100% across the platforms. High assay specificity (86-100%) for A(H5N1) rHA was achieved for sera from exposed or unexposed to hetorosubtype influenza HAs. In contrast, assay specificity for A(H1N1)pdm09 rHA using sera collected from A/Vietnam/1204/2004 (H5N1) vaccinees in 2008 was low (22-30%) in all platforms. Although cross-reactivity against rHA subtype proteins was observed in each assay platform, the correct subtype specific responses were identified 78%-94% of the time when paired samples were available for analysis. These results show that high throughput and portable multiplex assays that incorporate rHA can be used to identify influenza subtype specific infections.
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Affiliation(s)
- Zhu-Nan Li
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329-4027 USA.
| | | | | | - Bobbi J Horne
- Battelle Memorial Institute, Columbus, OH 43201, USA
| | - James Stevens
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329-4027 USA
| | | | - Jens Wrammert
- Emory Vaccine Center, Emory University, Atlanta, GA 30322, USA
| | | | | | - Kathy Hancock
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329-4027 USA
| | - Daniel B Jernigan
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329-4027 USA
| | - Min Levine
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329-4027 USA
| | - Jacqueline M Katz
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329-4027 USA.
| | - Joseph D Miller
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30329-4027 USA
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8
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Moore JH, van Opstal E, Kolling GL, Shin JH, Bogatcheva E, Nikonenko B, Einck L, Phipps AJ, Guerrant RL, Protopopova M, Warren CA. Treatment of Clostridium difficile infection using SQ641, a capuramycin analogue, increases post-treatment survival and improves clinical measures of disease in a murine model. J Antimicrob Chemother 2016; 71:1300-6. [PMID: 26832756 DOI: 10.1093/jac/dkv479] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Accepted: 12/14/2015] [Indexed: 12/31/2022] Open
Abstract
OBJECTIVES Clostridium difficile infection (CDI) is a primary cause of antibiotic-associated diarrhoeal illness. Current therapies are insufficient as relapse rates following antibiotic treatment range from 25% for initial treatment to 60% for treatment of recurrence. In this study, we looked at the efficacy of SQ641 in a murine model of CDI. SQ641 is an analogue of capuramycin, a naturally occurring nucleoside-based compound produced by Streptomyces griseus. METHODS In a series of experiments, C57BL/6 mice were treated with a cocktail of antibiotics and inoculated with C. difficile strain VPI10463. Animals were treated orally with SQ641 for 5 days at a dose range of 0.1-300 mg/kg/day, 20 mg/kg/day vancomycin or drug vehicle. Animals were monitored for disease severity, clostridial shedding and faecal toxin levels for 14 days post-infection. RESULTS Five day treatment of CDI with SQ641 resulted in higher 14 day survival rates in mice compared with either vancomycin or vehicle alone. CDI survival rates were 100% (13 of 13) and 94% (32 of 34), respectively, in the 1 and 10 mg/kg/day SQ641 treatment groups, 37% (7 of 19) with vancomycin treatment at 20 mg/kg/day and 32% (14 of 44) in the vehicle-only control group. Secondary measures of efficacy, such as prevention of weight loss, decreased disease severity, decreased C. difficile shedding and decreased toxin in faeces, were observed with SQ641 and vancomycin treatment. CONCLUSIONS SQ641 is effective for CDI treatment with prevention of relapse in the murine model of CDI.
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Affiliation(s)
- John H Moore
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA
| | - Edward van Opstal
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA
| | - Glynis L Kolling
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA
| | - Jae Hyun Shin
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA
| | | | | | - Leo Einck
- Sequella Inc., Rockville, MD 20850, USA
| | | | - Richard L Guerrant
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA
| | | | - Cirle Alcantara Warren
- Division of Infectious Diseases and International Health, University of Virginia, Charlottesville, VA 22908, USA
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9
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Heinrich N, Dawson R, du Bois J, Narunsky K, Horwith G, Phipps AJ, Nacy CA, Aarnoutse RE, Boeree MJ, Gillespie SH, Venter A, Henne S, Rachow A, Phillips PPJ, Hoelscher M, Diacon AH. Early phase evaluation of SQ109 alone and in combination with rifampicin in pulmonary TB patients. J Antimicrob Chemother 2015; 70:1558-66. [PMID: 25630641 DOI: 10.1093/jac/dku553] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Accepted: 12/09/2014] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVES SQ109, an asymmetrical diamine, is a novel anti-TB drug candidate. This first study in patients was done to determine safety, tolerability, pharmacokinetics and bacteriological effect of different doses of SQ109 alone and in combination with rifampicin when administered over 14 days. PATIENTS AND METHODS Smear-positive pulmonary TB patients were randomized into six groups of 15 to receive once-daily oral treatment with 75, 150 or 300 mg of SQ109, rifampicin (10 mg/kg body weight), rifampicin plus 150 mg of SQ109, or rifampicin plus 300 mg of SQ109 for 14 days. Patients were hospitalized for supervised treatment, regular clinical, biochemical and electrocardiographic safety assessments, pharmacokinetic profiling and daily overnight sputum collection. RESULTS SQ109 was safe and generally well tolerated. Mild to moderate dose-dependent gastrointestinal complaints were the most frequent adverse events. No relevant QT prolongation was noted. Maximum SQ109 plasma concentrations were lower than MICs. Exposure to SQ109 (AUC0-24) increased by drug accumulation upon repeated administration in the SQ109 monotherapy groups. Co-administration of SQ109 150 mg with rifampicin resulted in decreasing SQ109 exposures from day 1 to day 14. A higher (300 mg) dose of SQ109 largely outweighed the evolving inductive effect of rifampicin. The daily fall in log cfu/mL of sputum (95% CI) was 0.093 (0.126-0.059) with rifampicin, 0.133 (0.166-0.100) with rifampicin plus 150 mg of SQ109 and 0.089 (0.121-0.057) with rifampicin plus 300 mg of SQ109. Treatments with SQ109 alone showed no significant activity. CONCLUSIONS SQ109 alone or with rifampicin was safe over 14 days. Upon co-administration with rifampicin, 300 mg of SQ109 yielded a higher exposure than the 150 mg dose. SQ109 did not appear to be active alone or to enhance the activity of rifampicin during the 14 days of treatment.
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Affiliation(s)
- Norbert Heinrich
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany German Center for Infection Research (DZIF), Munich partner site, Munich, Germany
| | - Rodney Dawson
- Division of Pulmonology, Department of Medicine, Groote Schuur Hospital and University of Cape Town Lung Institute, Cape Town, South Africa
| | | | - Kim Narunsky
- Division of Pulmonology, Department of Medicine, Groote Schuur Hospital and University of Cape Town Lung Institute, Cape Town, South Africa
| | | | | | | | - Rob E Aarnoutse
- Radboud University Medical Center, Department of Pharmacy, Nijmegen, The Netherlands
| | | | | | - Amour Venter
- Medical Research Council Centre for Molecular and Cellular Biology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
| | - Sonja Henne
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany German Center for Infection Research (DZIF), Munich partner site, Munich, Germany
| | - Andrea Rachow
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany German Center for Infection Research (DZIF), Munich partner site, Munich, Germany
| | - Patrick P J Phillips
- Medical Research Council Clinical Trials Unit at University College London, London, UK
| | - Michael Hoelscher
- Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich, Munich, Germany German Center for Infection Research (DZIF), Munich partner site, Munich, Germany
| | - Andreas H Diacon
- TASK Applied Science, Cape Town, South Africa Medical Research Council Centre for Molecular and Cellular Biology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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10
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Haynes RAH, Zimmerman B, Millward L, Ware E, Premanandan C, Yu L, Phipps AJ, Lairmore MD. Early spatial and temporal events of human T-lymphotropic virus type 1 spread following blood-borne transmission in a rabbit model of infection. J Virol 2010; 84:5124-30. [PMID: 20219918 PMCID: PMC2863820 DOI: 10.1128/jvi.01537-09] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 02/13/2010] [Indexed: 01/13/2023] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) infection causes adult T-cell leukemia/lymphoma (ATL) and is associated with a variety of lymphocyte-mediated disorders. HTLV-1 transmission occurs by transmission of infected cells via breast-feeding by infected mothers, sexual intercourse, and contaminated blood products. The route of exposure and early virus replication events are believed to be key determinants of virus-associated spread, antiviral immune responses, and ultimately disease outcomes. The lack of knowledge of early events of HTLV-1 spread following blood-borne transmission of the virus in vivo hinders a more complete understanding of the immunopathogenesis of HTLV-1 infections. Herein, we have used an established animal model of HTLV-1 infection to study early spatial and temporal events of the viral infection. Twelve-week-old rabbits were injected intravenously with cell-associated HTLV-1 (ACH-transformed R49). Blood and tissues were collected at defined intervals throughout the study to test the early spread of the infection. Antibody and hematologic responses were monitored throughout the infection. HTLV-1 intracellular Tax and soluble p19 matrix were tested from ex vivo cultured lymphocytes. Proviral copy numbers were measured by real-time PCR from blood and tissue mononuclear leukocytes. Our data indicate that intravenous infection with cell-associated HTLV-1 targets lymphocytes located in both primary lymphoid and gut-associated lymphoid compartments. A transient lymphocytosis that correlated with peak virus detection parameters was observed by 1 week postinfection before returning to baseline levels. Our data support emerging evidence that HTLV-1 promotes lymphocyte proliferation preceding early viral spread in lymphoid compartments to establish and maintain persistent infection.
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Affiliation(s)
- Rashade A. H. Haynes
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Bevin Zimmerman
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Laurie Millward
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Evan Ware
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Christopher Premanandan
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Lianbo Yu
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Andrew J. Phipps
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
| | - Michael D. Lairmore
- Department of Veterinary Biosciences, Center for Biostatistics, Center for Retrovirus Research and Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio 43210
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11
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Haynes RAH, Phipps AJ, Yamamoto B, Green P, Lairmore MD. Development of a cytotoxic T-cell assay in rabbits to evaluate early immune response to human T-lymphotropic virus type 1 infection. Viral Immunol 2010; 22:397-405. [PMID: 19951176 DOI: 10.1089/vim.2009.0059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1) infection causes adult T-cell lymphoma/leukemia (ATL) following a prolonged clinical incubation period, despite a robust adaptive immune response against the virus. Early immune responses that allow establishment of the infection are difficult to study without effective animal models. We have developed a cytotoxic T-lymphocyte (CTL) assay to monitor the early events of HTLV-1 infection in rabbits. Rabbit skin fibroblast cell lines were established by transformation with a plasmid expressing simian virus 40 (SV40) large T antigen and used as autochthonous targets (derived from same individual animal) to measure CTL activity against HTLV-1 infection in rabbits. Recombinant vaccinia virus (rVV) constructs expressing either HTLV-1 envelope surface unit (SU) glycoprotein 46 or Tax proteins were used to infect fibroblast targets in a (51)Cr-release CTL assay. Rabbits inoculated with Jurkat T cells or ACH.2 cells (expressing ACH HTLV-1 molecule clone) were monitored at 0, 2, 4, 6, 8, 13, 21, and 34 wk post-infection. ACH.2-inoculated rabbits were monitored serologically and for viral infected cells following ex vivo culture. Proviral load analysis indicated that rabbits with higher proviral loads had significant CTL activity against HTLV-1 SU as early as 2 wk post-infection, while both low- and high-proviral-load groups had minimal Tax-specific CTL activity throughout the study. This first development of a stringent assay to measure HTLV-1 SU and Tax-specific CTL assay in the rabbit model will enhance immunopathogenesis studies of HTLV-1 infection. Our data suggest that during the early weeks following infection, HTLV-1-specific CTL responses are primarily targeted against Env-SU.
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Affiliation(s)
- Rashade A H Haynes
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210-1093, USA
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12
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Schumacher WC, Phipps AJ, Dutta PK. Detection of Bacillus anthracis spores: comparison of quantum dot and organic dye labeling agents. ADV POWDER TECHNOL 2009. [DOI: 10.1016/j.apt.2009.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Premanandan C, Storozuk CA, Clay CD, Lairmore MD, Schlesinger LS, Phipps AJ. Complement protein C3 binding to Bacillus anthracis spores enhances phagocytosis by human macrophages. Microb Pathog 2009; 46:306-14. [DOI: 10.1016/j.micpath.2009.03.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2008] [Revised: 03/16/2009] [Accepted: 03/18/2009] [Indexed: 11/26/2022]
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14
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Byun Y, Vogel SR, Phipps AJ, Carnrot C, Eriksson S, Tiwari R, Tjarks W. Synthesis and biological evaluation of inhibitors of thymidine monophosphate kinase from Bacillus anthracis. Nucleosides Nucleotides Nucleic Acids 2008; 27:244-60. [PMID: 18260009 DOI: 10.1080/15257770701845238] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Nineteen lipophilic thymidine phosphate-mimicking compounds were designed and synthesized as potential inhibitors of thymidine monophosphate kinase of Bacillus anthracis, a Gram-positive bacterium that causes anthrax. These thymidine analogues were substituted at the 5'-postion with sulfonamide-, amide-, (thio)urea-, or triazole groups, which served as lipophilic surrogates for phosphate. Three of the tested compounds produced inhibition of B. anthracis Sterne growth and/or thymidine monophosphate activity. Additional studies will be necessary to elucidate the potential of this type of B. anthracis thymidine monophosphate inhibitors as novel antibiotics in the treatment of anthrax.
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Affiliation(s)
- Youngjoo Byun
- Department of Radiology, Johns Hopkins Medical Institutions, Baltimore, MD, USA
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15
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Datta A, Silverman L, Phipps AJ, Hiraragi H, Ratner L, Lairmore MD. Human T-lymphotropic virus type-1 p30 alters cell cycle G2 regulation of T lymphocytes to enhance cell survival. Retrovirology 2007; 4:49. [PMID: 17634129 PMCID: PMC1937004 DOI: 10.1186/1742-4690-4-49] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Accepted: 07/16/2007] [Indexed: 12/18/2022] Open
Abstract
Background Human T-lymphotropic virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma and is linked to a number of lymphocyte-mediated disorders. HTLV-1 contains both regulatory and accessory genes in four pX open reading frames. pX ORF-II encodes two proteins, p13 and p30, whose roles are still being defined in the virus life cycle and in HTLV-1 virus-host cell interactions. Proviral clones of HTLV-1 with pX ORF-II mutations diminish the ability of the virus to maintain viral loads in vivo. p30 expressed exogenously differentially modulates CREB and Tax-responsive element-mediated transcription through its interaction with CREB-binding protein/p300 and while acting as a repressor of many genes including Tax, in part by blocking tax/rex RNA nuclear export, selectively enhances key gene pathways involved in T-cell signaling/activation. Results Herein, we analyzed the role of p30 in cell cycle regulation. Jurkat T-cells transduced with a p30 expressing lentivirus vector accumulated in the G2-M phase of cell cycle. We then analyzed key proteins involved in G2-M checkpoint activation. p30 expression in Jurkat T-cells resulted in an increase in phosphorylation at serine 216 of nuclear cell division cycle 25C (Cdc25C), had enhanced checkpoint kinase 1 (Chk1) serine 345 phosphorylation, reduced expression of polo-like kinase 1 (PLK1), diminished phosphorylation of PLK1 at tyrosine 210 and reduced phosphorylation of Cdc25C at serine 198. Finally, primary human lymphocyte derived cell lines immortalized by a HTLV-1 proviral clone defective in p30 expression were more susceptible to camptothecin induced apoptosis. Collectively these data are consistent with a cell survival role of p30 against genotoxic insults to HTLV-1 infected lymphocytes. Conclusion Collectively, our data are the first to indicate that HTLV-1 p30 expression results in activation of the G2-M cell cycle checkpoint, events that would promote early viral spread and T-cell survival.
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Affiliation(s)
- Antara Datta
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
| | - Lee Silverman
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Drug Safety and Disposition, Millenium Pharmaceuticals, Inc., 45 Sidney Street, Cambridge, Massachusetts, USA
| | - Andrew J Phipps
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
| | - Hajime Hiraragi
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Genentech, Inc. MS68, 1 DNA Way, South San Francisco, California, USA
| | - Lee Ratner
- Department of Medicine, Pathology, and Molecular Microbiology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Michael D Lairmore
- Center for Retrovirus Research, The Ohio State University, Columbus, Ohio, USA
- Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio, USA
- Ohio State Biochemistry Program, The Ohio State University, Columbus, Ohio, USA
- Comprehensive Cancer Center, Arthur G. James Cancer Hospital and Solove Research Institute, The Ohio State University, Columbus, Ohio, USA
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16
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Premanandan C, Lairmore MD, Fernandez S, Phipps AJ. Quantitative measurement of anthrax toxin receptor messenger RNA in primary mononuclear phagocytes. Microb Pathog 2006; 41:193-8. [PMID: 16854559 DOI: 10.1016/j.micpath.2006.05.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 05/22/2006] [Accepted: 05/23/2006] [Indexed: 11/28/2022]
Abstract
Two anthrax toxin receptors have been identified, tumor endothelial marker 8 (TEM8) and capillary morphogenesis protein 2 (CMG2). Both receptors have been shown to be capable of facilitating the entry of Bacillus anthracis exotoxins into the cytosol of susceptible cells. The levels of TEM8 and CMG2 RNA transcripts present in human primary macrophages derived from multiple unrelated donors and primary mouse macrophages have not been well described. In this communication, we examined the expression of mRNA transcripts of TEM8 and CMG2 in primary human and mouse macrophages and mouse tissues by standard and quantitative real-time RT-PCR. Our results indicate that CMG2 transcripts are preferentially expressed over TEM8 transcripts in primary human and mouse macrophages as compared to immortalized cell lines.
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Affiliation(s)
- Christopher Premanandan
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210-1093, USA
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17
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Hiraragi H, Kim SJ, Phipps AJ, Silic-Benussi M, Ciminale V, Ratner L, Green PL, Lairmore MD. Human T-lymphotropic virus type 1 mitochondrion-localizing protein p13(II) is required for viral infectivity in vivo. J Virol 2006; 80:3469-76. [PMID: 16537614 PMCID: PMC1440407 DOI: 10.1128/jvi.80.7.3469-3476.2006] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Human T-lymphotropic virus type 1 (HTLV-1), the etiological agent of adult T-cell leukemia, encodes unique regulatory and accessory proteins in the pX region of the provirus, including the open reading frame II product p13(II). p13(II) localizes to mitochondria, binds farnesyl pyrophosphate synthetase, an enzyme involved in posttranslational farnesylation of Ras, and alters Ras-dependent cell signaling and control of apoptosis. The role of p13(II) in virus infection in vivo remains undetermined. Herein, we analyzed the functional significance of p13(II) in HTLV-1 infection. We compared the infectivity of a human B-cell line that harbors an infectious molecular clone of HTLV-1 with a selective mutation that prevents the translation of p13(II) (729.ACH.p13) to the infectivity of a wild-type HTLV-1-expressing cell line (729.ACH). 729.ACH and 729.ACH.p13 producer lines had comparable infectivities for cultured rabbit peripheral blood mononuclear cells (PBMC), and the fidelity of the start codon mutation in ACH.p13 was maintained after PBMC passage. In contrast, zero of six rabbits inoculated with 729.ACH.p13 cells failed to establish viral infection, whereas six of six rabbits inoculated with wild-type HTLV-1-expressing cells (729.ACH) were infected as measured by antibody responses, proviral load, and HTLV-1 p19 matrix antigen production from ex vivo-cultured PBMC. Our data are the first to indicate that the HTLV-1 mitochondrion-localizing protein p13(II) has an essential biological role during the early phase of virus infection in vivo.
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MESH Headings
- Animals
- Antibodies, Viral/metabolism
- Blotting, Western
- Cell Line, Tumor
- Cells, Cultured
- Coculture Techniques
- Codon, Initiator
- Disease Models, Animal
- Enzyme-Linked Immunosorbent Assay
- Female
- Gene Products, gag/blood
- Genome, Viral
- Geranyltranstransferase/physiology
- HTLV-I Infections/virology
- Human T-lymphotropic virus 1/genetics
- Human T-lymphotropic virus 1/immunology
- Human T-lymphotropic virus 1/pathogenicity
- Human T-lymphotropic virus 1/physiology
- Humans
- Leukocytes, Mononuclear/virology
- Mitochondria/enzymology
- Mutation
- Polymerase Chain Reaction
- Proviruses/genetics
- Proviruses/isolation & purification
- Rabbits
- Retroviridae Proteins, Oncogenic/blood
- Viral Load
- gag Gene Products, Human Immunodeficiency Virus
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Affiliation(s)
- Hajime Hiraragi
- Center for Retrovirus Research and Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, OH 43210, USA
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18
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Arnold J, Yamamoto B, Li M, Phipps AJ, Younis I, Lairmore MD, Green PL. Enhancement of infectivity and persistence in vivo by HBZ, a natural antisense coded protein of HTLV-1. Blood 2006; 107:3976-82. [PMID: 16424388 PMCID: PMC1895283 DOI: 10.1182/blood-2005-11-4551] [Citation(s) in RCA: 152] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Natural antisense viral transcripts have been recognized in retroviruses, including human T-cell leukemia virus type 1 (HTLV-1), HIV-1, and feline immunodeficiency virus (FIV), and have been postulated to encode proteins important for the infection cycle and/or pathogenesis of the virus. The antisense strand of the HTLV-1 genome encodes HBZ, a novel nuclear basic region leucine zipper (b-ZIP) protein that in overexpression assays down-regulates Tax oncoprotein-induced viral transcription. Herein, we investigated the contribution of HBZ to HTLV-1-mediated immortalization of primary T lymphocytes in vitro and HTLV-1 infection in a rabbit animal model. HTLV-1 HBZ mutant viruses were generated and evaluated for viral gene expression, protein production, and immortalization capacity. Biologic properties of HBZ mutant viruses in vitro were indistinguishable from wild-type HTLV-1, providing the first direct evidence that HBZ is dispensable for viral replication and cellular immortalization. Rabbits inoculated with irradiated cells expressing HTLV-1 HBZ mutant viruses became persistently infected. However, these rabbits displayed a decreased antibody response to viral gene products and reduced proviral copies in peripheral blood mononuclear cells (PBMCs) as compared with wild-type HTLV-1-infected animals. Our findings indicated that HBZ was not required for in vitro cellular immortalization, but enhanced infectivity and persistence in inoculated rabbits. This study demonstrates that retroviruses use negative-strand-encoded proteins in the establishment of chronic viral infections.
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Affiliation(s)
- Joshua Arnold
- Department of Veterinary Biosciences, The Ohio State University, 1925 Coffey Road, Columbus, OH 43210, USA
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19
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Carnrot C, Vogel SR, Byun Y, Wang L, Tjarks W, Eriksson S, Phipps AJ. Evaluation of Bacillus anthracis thymidine kinase as a potential target for the development of antibacterial nucleoside analogs. Biol Chem 2006; 387:1575-81. [PMID: 17132103 DOI: 10.1515/bc.2006.196] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Bacillus anthracis, which causes anthrax, has attracted attention because of its potential use as a biological weapon. The risk of multidrug resistance against B. anthracis increases the need for antibiotics with new molecular targets. Nucleoside analogs are well-known antiviral and anticancer prodrugs, and thymidine kinase catalyzes the rate-limiting step in the activation of pyrimidine nucleoside analogs used in chemotherapy. The thymidine kinase gene from B. anthracis Sterne strain (34F2) (Ba-TK) was cloned and expressed in E. coli, and the product was purified and characterized regarding its substrate specificity. Ba-TK phosphorylated pyrimidine nucleosides and all natural nucleoside triphosphates served as phosphate donors. Size exclusion chromatography indicated a dimeric form of Ba-TK, regardless of the presence of ATP. Thymidine was the most efficient substrate with a low K(m) value (0.6 microM) and a V(max) of 3.3 micromol dTMP mg(-1) min(-1), but deoxyuridine (K(m)=4.2 microM, V(max)=4.1 micromol dUMP mg(-1) min(-1)) was also a good substrate. Several pyrimidine analogs were also tested and analogs with 5-position modifications showed higher activities compared to analogs with 3'- and N3-position modifications. Deoxyuridine analogs were the most potent inhibitors of B. anthracis growth in vitro. These results may be used to guide future development of nucleoside analogs against B. anthracis.
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Affiliation(s)
- Cecilia Carnrot
- Department of Molecular Biosciences, The Swedish University of Agricultural Biosciences, Biomedical Center, P.O. Box 575, S-751 23 Uppsala, Sweden
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20
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Silverman LR, Phipps AJ, Montgomery A, Fernandez S, Tsukahara T, Ratner L, Lairmore MD. In vivo analysis of replication and immunogenicity of proviral clones of human T-lymphotropic virus type 1 with selective envelope surface-unit mutations. Blood 2005; 106:3602-8. [PMID: 16046523 PMCID: PMC1895059 DOI: 10.1182/blood-2005-03-1076] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2005] [Accepted: 07/20/2005] [Indexed: 11/20/2022] Open
Abstract
Human T-cell leukemia virus type 1 (HTLV-1) is the causative agent of adult T-cell lymphoma/leukemia (ATL). The HTLV-1 envelope gene exhibits limited variability when examined from infected individuals, but has not been tested using infectious clones of the virus in animal models. In vitro assays indicate that HTLV-1 envelope (Env) Ser75Ile, Asn95Asp, and Asn195Asp surface unit (SU) mutants are able to replicate in and immortalize lymphocytes. Herein, we examined the effects of these Env mutants in rabbits inoculated with HTLV-1 immortalized ACH.75, ACH.95, or ACH.195 cell lines (expressing full-length molecular clones with the SU mutations) or the ACH.1 cell line (expressing wild-type SU). All rabbits became infected, and the fidelity of the mutations was maintained throughout the 8-week study. However, SU point mutations resulted in decreased antibody responses to viral group-associated antigen (Gag) and Env antigens. ACH.195 rabbits had a selective decreased antibody response to SU, and one ACH.195 rabbit had an antibody response to both HTLV-1 and HTLV-2 SUs. Some mutant inoculation groups had altered proviral loads. However, peripheral-blood mononuclear cell (PBMC) proviral loads did not correlate with antibody responses. Our data are the first to demonstrate that mutations in critical determinants of HTLV-1 Env SU altered antibody responses and proviral loads, but do not prevent viral replication in vivo.
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Affiliation(s)
- Lee R Silverman
- Center for Retrovirus Research and Department of Veterinary Biosciences, the Center for Biostatistics, The Ohio State University, Columbus, 43210, USA
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21
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Hayes KA, Köksoy S, Phipps AJ, Buck WR, Kociba GJ, Mathes LE. Lentivirus-specific cytotoxic T-lymphocyte responses are rapidly lost in thymectomized cats infected with feline immunodeficiency virus. J Virol 2005; 79:8237-42. [PMID: 15956569 PMCID: PMC1143713 DOI: 10.1128/jvi.79.13.8237-8242.2005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
To what extent the thymus is needed to preserve the virus-specific cytotoxic T-lymphocyte (CTL) response of lentivirus-infected adults is unclear. Presented here is the first definitive study using thymectomized (ThX) animals to directly evaluate the contribution of thymic function to lentivirus-specific CTL response and the control of lentivirus infections. ThX and mock-ThX cats were inoculated with feline immunodeficiency virus (FIV) and monitored for their FIV-specific CTL responses. Early in infection, both FIV-ThX and FIV-mock-ThX cats produced similar CTL responses, but surprisingly, after 20 weeks, the FIV-ThX cats showed a statistically significant loss of FIV-specific CTL activity, while FIV-infected cats with intact thymuses continued to maintain FIV-specific CTL. The loss of CTL did not affect plasma virus load, which remained elevated for both groups. These results emphasize the importance of thymic integrity in maintaining immunity to lentiviruses, but also bring into question the notion that virus load is regulated predominantly by the virus-specific CTL response.
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Affiliation(s)
- Kathleen A Hayes
- Department of Veterinary Biosciences, Center for Retrovirus Research, The Ohio State University, 1925 Coffey Road, Columbus, Ohio 43210, USA
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22
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Porter RJ, Phipps AJ, Gallagher P, Scott A, Stevenson PS, O'Brien JT. Effects of acute tryptophan depletion on mood and cognitive functioning in older recovered depressed subjects. Am J Geriatr Psychiatry 2005; 13:607-15. [PMID: 16009737 DOI: 10.1176/appi.ajgp.13.7.607] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVE Previous studies show that acute tryptophan depletion (ATD), by administration of an amino acid drink lacking tryptophan, can produce clinically significant depressive symptoms in subjects who have recovered from major depression. This is more likely in female patients who have had suicidal ideation, recurrent depression, and treatment with specific serotonin reuptake inhibitors. These risk factors are frequent in older recovered depressed people. The authors investigated the effects of ATD on mood and cognitive functioning in this group. METHODS Sixteen recovered depressed (RD) subjects and 17 healthy-comparison subjects, over 60 years old, participated in a double-blind, placebo-controlled, crossover study involving administration of a tryptophan-depleting and a placebo drink. Mood ratings scales were administered at baseline and at 4 and 7 hours post-drink on each test day. A battery of neuropsychological tests, including the modified Mini-Mental State Examination (MMSE) was administered between 4 and 6 hours post-drink. RESULTS Depletion of plasma free tryptophan was 71% at 4 and 7 hours after the active drink. There was no evidence of mood change at any time in either group. On the MMSE, however, the ATD/RD group showed a significant decrease compared with placebo. CONCLUSIONS There was no evidence of mood disturbance during ATD in any subject. This may imply less sensitivity to acute disturbance of the 5HT system than in younger recovered patients.
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Affiliation(s)
- Richard J Porter
- Dept. of Psychological Medicine, P.O. Box 4345, Christchurch, New Zealand.
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24
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Abstract
The intentional use of Bacillus anthracis, the etiological agent of anthrax, as a bioterrorist weapon in late 2001 made our society acutely aware of the importance of developing, testing, and stockpiling adequate countermeasures against biological attacks. Biodefense vaccines are an important component of our arsenal to be used during a biological attack. However, most of the agents considered significant threats either have been eradicated or rarely infect humans alive today. As such, vaccine efficacy cannot be determined in human clinical trials but must be extrapolated from experimental animal models. This article reviews the efficacy and immunogenicity of human anthrax vaccines in well-defined animal models and the progress toward developing a rugged immunologic correlate of protection. The ongoing evaluation of human anthrax vaccines will be dependent on animal efficacy data in the absence of human efficacy data for licensure by the U.S. Food and Drug Administration.
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Affiliation(s)
- Andrew J Phipps
- Department of Veterinary Biosciences, The Ohio State University, Columbus, OH 43210-1093, USA.
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25
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Silverman LR, Phipps AJ, Montgomery A, Ratner L, Lairmore MD. Human T-cell lymphotropic virus type 1 open reading frame II-encoded p30II is required for in vivo replication: evidence of in vivo reversion. J Virol 2004; 78:3837-45. [PMID: 15047799 PMCID: PMC374265 DOI: 10.1128/jvi.78.8.3837-3845.2004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Human T-cell lymphotropic virus type 1 (HTLV-1) causes adult T-cell leukemia/lymphoma and exhibits high genetic stability in vivo. HTLV-1 contains four open reading frames (ORFs) in its pX region. ORF II encodes two proteins, p30(II) and p13(II), both of which are incompletely characterized. p30(II) localizes to the nucleus or nucleolus and has distant homology to the transcription factors Oct-1, Pit-1, and POU-M1. In vitro studies have demonstrated that at low concentrations, p30(II) differentially regulates cellular and viral promoters through an interaction with CREB binding protein/p300. To determine the in vivo significance of p30(II), we inoculated rabbits with cell lines expressing either a wild-type clone of HTLV-1 (ACH.1) or a clone containing a mutation in ORF II, which eliminated wild-type p30(II) expression (ACH.30.1). ACH.1-inoculated rabbits maintained higher HTLV-1-specific antibody titers than ACH.30.1-inoculated rabbits, and all ACH.1-inoculated rabbits were seropositive for HTLV-1, whereas only two of six ACH.30.1-inoculated rabbits were seropositive. Provirus could be consistently PCR amplified from peripheral blood mononuclear cell (PBMC) DNA in all ACH.1-inoculated rabbits but in only three of six ACH.30.1-inoculated rabbits. Quantitative competitive PCR indicated higher PBMC proviral loads in ACH.1-inoculated rabbits. Interestingly, sequencing of ORF II from PBMC of provirus-positive ACH.30.1-inoculated rabbits revealed a reversion to wild-type sequence with evidence of early coexistence of mutant and wild-type sequence. Our data provide evidence that HTLV-1 must maintain its key accessory genes to survive in vivo and that in vivo pressures select for maintenance of wild-type ORF II gene products during the early course of infection.
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Affiliation(s)
- Lee R Silverman
- Center for Retrovirus Research and Department of Veterinary Biosciences, The Ohio State University, Columbus, Ohio 43210, USA
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26
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Abstract
BACKGROUND Memory clinics have developed using a range of service models but providing similar functions which include assessment, information, treatment monitoring, education, training and research. Memory clinic development is now taking place in the UK in the context of clinical governance and the drive for quality improvement. At a strategic level this process is driven by the National Service Framework for Older People and the National Institute for Clinical Excellence. METHODS The literature describing quality issues in memory clinics is reviewed against a multi-dimensional framework for assessing quality standards. RESULTS AND CONCLUSIONS The rationing of health care, both explicit and implicit, is discussed in view of limited capacity and financial resources of the National Health Service and the significance of this in determining quality standards is highlighted. The authors offer a generic quality specification for memory clinic development, using mild cognitive impairment as an illustration of the quality standards that might be achieved and clinical governance systems that must be present to drive forward continuous quality improvement.
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Abstract
CTL assays in outbred cats have been difficult to perform because of a lack of a good source of syngeneic target cell. Primary fibroblasts from cats are widely used as target cells for MHC-restricted cytotoxic T-cell (CTL) assays, but their limited life-spans of 8-10 culture passages can be problematic for longitudinal studies. To circumvent the life-span limitations of primary fibroblast cultures, we developed a procedure for immortalizing feline primary fibroblast cells by transfection with a molecular clone of simian virus 40 (SV40). Fibroblast cultures from skin biopsies of 28 cats were immortalized using this procedure and have been passaged for longer than 6 months without showing any phenotypic difference from the original primary cells. Non-SV40 transfected feline fibroblasts from a selection of animals in the same group survived for only 6-8 weeks before reaching senescence. The immortalized fibroblasts expressed SV40 T-antigen and Class I MHC protein, and were successfully used as target cells in 51Cr release CTL assays in feline immunodeficiency virus (FIV)-infected cats and in vitro stimulated allogeneic T-cell cultures.
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MESH Headings
- Animals
- Antigens, Polyomavirus Transforming/biosynthesis
- Antigens, Polyomavirus Transforming/genetics
- Antigens, Polyomavirus Transforming/immunology
- Cats/immunology
- Cell Transformation, Viral/genetics
- Cell Transformation, Viral/immunology
- Cellular Senescence/physiology
- Chromium Radioisotopes
- Cytotoxicity Tests, Immunologic/methods
- Cytotoxicity Tests, Immunologic/veterinary
- Epitopes, T-Lymphocyte/immunology
- Fibroblasts/cytology
- Fibroblasts/immunology
- Fluorescent Antibody Technique/veterinary
- Histocompatibility Antigens Class I/biosynthesis
- Histocompatibility Antigens Class I/genetics
- Histocompatibility Antigens Class II/biosynthesis
- Histocompatibility Antigens Class II/genetics
- Immunodeficiency Virus, Feline/isolation & purification
- Isoantigens/immunology
- Simian virus 40/immunology
- Specific Pathogen-Free Organisms
- T-Lymphocytes, Cytotoxic/immunology
- Transfection/veterinary
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Affiliation(s)
- S Köksoy
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, 1925 Coffey Rd., Columbus, OH 43210,USA
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28
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Abstract
Feline leukemia virus (FeLV) subgroup B arises de novo through recombination between the env genes of exogenous FeLV subgroup A and endogenous FeLV-like sequences. FeLV-B, which by itself is poorly infectious, will increase to high titer in the presence of FeLV-A, and is associated with FeLV-related neoplastic disease. Although the participation of FeLV-B in disease progression has not been definitively proven, circumstantial evidence supports the hypothesis that the generation of FeLV-B is linked to disease progression. The present study was designed to evaluate whether increasing the levels of FeLV-B early in FeLV-A infection could result in reduction of the incubation period for development of neoplastic disease. For this study, an isolate of FeLV-B, designated FeLV-1B3, was biologically cloned, partially sequenced, and subgroup typed. In in vivo studies, none of the neonatal cats inoculated with FeLV-1B3 alone converted to viremia positive, and all remained healthy throughout the observation period. All of the kittens inoculated with FeLV-A alone became chronically viremic, and those held for long-term observation all developed either neoplastic disease or anemia. However, kittens inoculated with the combination of FeLV-1B3 and FeLV-A showed attenuated infections whereby the majority of cats failed to develop chronic viremia. The apparent interference of FeLV-A infection by FeLV-B was time and titer dependent. This unexpected result suggests that FeLV-B may act as an attenuated virus, causing inhibition of FeLV-A possibly through an immune-mediated mechanism. Partial support for this view was provided by postmortem examination of cats inoculated with FeLV-1B3 alone. Even though none of these cats became viremic, FeLV antigen was detected as focal infections in select tissues, especially salivary gland epithelium, where enough antigen may be expressed to provide an immunizing dose against gag and pol cross-reacting antigens. This work may also provide another approach to vaccine development based on endogenous retrovirus vector systems.
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MESH Headings
- Amino Acid Sequence
- Animals
- Animals, Newborn
- Antibody Formation
- Antigens, Viral/analysis
- Cats
- Cloning, Molecular
- Disease Progression
- Genes, env
- Leukemia Virus, Feline/classification
- Leukemia Virus, Feline/genetics
- Leukemia Virus, Feline/pathogenicity
- Leukemia, Feline/immunology
- Leukemia, Feline/pathology
- Leukemia, Feline/physiopathology
- Leukemia, Feline/virology
- Molecular Sequence Data
- Polymerase Chain Reaction
- Recombination, Genetic
- Sequence Alignment
- Sequence Homology, Amino Acid
- Terminal Repeat Sequences
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Affiliation(s)
- A J Phipps
- Department of Veterinary Biosciences, The Center for Retrovirus Research, Comprehensive Cancer Center, The Ohio State University, 1925 Coffey Road, Columbus, Ohio, 43210, USA
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29
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Hayes KA, Phipps AJ, Francke S, Mathes LE. Antiviral therapy reduces viral burden but does not prevent thymic involution in young cats infected with feline immunodeficiency virus. Antimicrob Agents Chemother 2000; 44:2399-405. [PMID: 10952586 PMCID: PMC90076 DOI: 10.1128/aac.44.9.2399-2405.2000] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The thymus is a major target organ in human immunodeficiency virus type 1 (HIV-1)-infected children and feline immunodeficiency virus (FIV)-infected young cats (G. A. Dean and N. C. Pedersen, J. Virol. 72:9436-9440, 1998; J. L. Heeney, Immunol. Today 16:515-520, 1995; S. M. Schnittman et al., Proc. Natl. Acad. Sci. USA 87:7727-7731, 1990; T. A. Seemayer et al., Hum. Pathol. 15:469-474, 1984; H.-J. Shuurn et al., Am. J. Pathol. 134:1329-1338, 1989; J. C. Woo et al., J. Virol. 71:8632-8641, 1997; J. C. Woo et al., AIDS Res. Hum. Retrovir. 15:1377-1388, 1999). It is likely that the accelerated disease process in children and cats is due to infection of the thymus during the time when generation of naive T lymphocytes is needed for development of the mature immune system. Zidovudine (ZDV) monotherapy, which is used to prevent and treat perinatal HIV-1 infection (R. Sperling, Infect. Dis. Obstet. Gynecol. 6:197-203, 1998), previously had been shown to reduce viral burden in FIV-infected young cats (K. A. Hayes et al., J. Acquir. Immune Defic. Syndr. 6:127-134, 1993). The purpose of this study was to evaluate the effect of drug-induced reduction of viral burden in the thymus on virus-mediated thymic involution and peripheral blood CD4 decline using FIV-infected cats as a model for pediatric HIV-1 infection. Eight-week-old cats were randomly assigned to uninfected, saline-treated; uninfected, ZDV-treated; FIV-infected, saline-treated; and FIV-infected, ZDV-treated groups. Parameters measured included blood lymphocyte numbers, viral load in blood and thymic tissue, and thymic histopathology. While the viral burden was significantly reduced by ZDV monotherapy in peripheral blood lymphocytes, plasma, and thymus, thymic lesions were similar for the treated and untreated FIV-infected cats. Further, markedly lowering the viral burden did not increase blood CD4 lymphocyte numbers or prevent their decline. The data suggest that an inflammatory process continued in spite of reduced virus replication. These observations imply that reducing virus load and limiting thymic inflammation are separate factors that must be addressed when considering therapeutic strategies aimed at preserving thymic function.
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Affiliation(s)
- K A Hayes
- Department of Veterinary Biosciences, The Ohio State University, Columbus 43210, USA
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30
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Phipps AJ, Chen H, Hayes KA, Roy-Burman P, Mathes LE. Differential pathogenicity of two feline leukemia virus subgroup A molecular clones, pFRA and pF6A. J Virol 2000; 74:5796-801. [PMID: 10846058 PMCID: PMC112073 DOI: 10.1128/jvi.74.13.5796-5801.2000] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/1999] [Accepted: 03/29/2000] [Indexed: 11/20/2022] Open
Abstract
F6A, a molecular clone of subgroup A feline leukemia virus (FeLV) is considered to be highly infectious but weakly pathogenic. In recent studies with a closely related subgroup A molecular clone, FRA, we demonstrated high pathogenicity and a strong propensity to undergo recombination with endogenous FeLV (enFeLV), leading to a high frequency of transition from subgroup A to A/B. The present study was undertaken to identify mechanisms of FeLV pathogenesis that might become evident by comparing the two closely related molecular clones. F6A was shown to have an infectivity similar to that of FRA when delivered as a provirus. Virus load and antibody responses were also similar, although F6A-infected cats consistently carried higher virus loads than FRA-infected cats. However, F6A-infected cats were slower to undergo de novo recombination with enFeLV and showed slower progression to disease than FRA-infected cats. Tumors collected from nine pF6A- or pFRA-inoculated cats expressed lymphocyte markers for T cells (seven tumors) and B cells (one tumor), and non-T/B cells (one tumor). One cat with an A-to-A/C conversion developed erythrocyte hypoplasia. Genomic mapping of recombinants from pF6A- and pFRA-inoculated cats revealed similar crossover sites, suggesting that the genomic makeup of the recombinants did not contribute to increased progression to neoplastic disease. From these studies, the mechanism most likely to account for the pathologic differences between F6A and FRA is the lower propensity for F6A to undergo de novo recombination with enFeLV in vivo. A lower recombination rate is predicted to slow the transition from subgroup A to A/B and slow the progression to disease.
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MESH Headings
- Amino Acid Sequence
- Anemia, Aplastic/virology
- Animals
- Antibodies, Viral/immunology
- Cats
- Cloning, Molecular
- DNA, Viral/physiology
- Genes, env
- Leukemia Virus, Feline/genetics
- Leukemia Virus, Feline/immunology
- Leukemia Virus, Feline/isolation & purification
- Leukemia Virus, Feline/pathogenicity
- Molecular Sequence Data
- Phenotype
- Plasmids/physiology
- Recombination, Genetic
- Viremia
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Affiliation(s)
- A J Phipps
- Department of Veterinary Biosciences, The Ohio State University, Columbus 43210, USA
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31
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Beall CJ, Phipps AJ, Mathes LE, Stromberg P, Johnson PR. Transfer of the feline erythropoietin gene to cats using a recombinant adeno-associated virus vector. Gene Ther 2000; 7:534-9. [PMID: 10757028 DOI: 10.1038/sj.gt.3301126] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Chronic renal failure and the associated erythropoietin-responsive anemia afflicts over 2 million domestic cats in the United States, resulting in morbidity that can affect the owner-pet relationship. Although treatment of cats with recombinant human erythropoietin (Epo) protein can be effective, response to the drug often dissipates over time, probably due to the development of antibodies reactive with the human protein. As an alternate approach to the treatment of this disease, we have developed a recombinant adeno-associated virus vector containing the feline erythropoietin gene (rAAV/feEpo). This vector, when administered intramuscularly to normal healthy cats, caused a dose-related increase in hematocrit over a 7-week period after injection. Thus, the rAAV/feEpo vector holds promise as a simple, safe and effective therapy for the anemia of chronic renal failure in domestic cats.
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Affiliation(s)
- C J Beall
- Children's Research Institute, Children's Hospital, Inc, Columbus, OH 43205, USA
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32
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Phipps AJ, Hayes KA, Buck WR, Podell M, Mathes LE. Neurophysiologic and immunologic abnormalities associated with feline immunodeficiency virus molecular clone FIV-PPR DNA inoculation. J Acquir Immune Defic Syndr 2000; 23:8-16. [PMID: 10708051 DOI: 10.1097/00126334-200001010-00002] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Although direct feline immunodeficiency virus (FIV) proviral DNA inoculation has been shown to be infectious in cats, long-term studies to assess the pathogenic nature of DNA inoculation are lacking. We have recently reported that direct feline leukemia virus (FeLV) DNA inoculation resulted in infection and the development of FeLV-related disease end points with similar temporal expression and virulence to that of cats infected with whole virus. We show in this study that pFIV-PPR DNA inoculation resulted in infection of cats and the development of FIV-related immunologic and neurologic abnormalities. Infected cats demonstrated progressive loss of CD4+ lymphocytes resulting in decreased CD4:CD8 ratios. Neurologic dysfunction was demonstrated by increased bilateral frontal lobe slow-wave activity. Prolongation of the visual evoked potential peak latency onset response pattern also supported a similar progression of abnormal cortical response. Furthermore, histopathologic examination revealed lesions attributed to FIV infection in lymph node, thymus, brain, and lung. Finally, nested polymerase chain reaction detected FIV provirus in brain, bone marrow, mesenteric lymph node, thymus, spleen, tonsil, and liver. These results confirm that FIV DNA inoculation is an efficient model for study of the pathogenic nature of molecular clones in vivo and offers the opportunity to measure temporal genomic stability of a homogeneous challenge material.
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Affiliation(s)
- A J Phipps
- Department of Veterinary Biosciences, College of Veterinary Medicine, The Ohio State University, Columbus, USA
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33
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Abstract
Ecotropic feline leukemia viruses subgroup A (FeLV-A) is known to recombine with endogenous FeLV (enFeLV) env elements yielding polytropic FeLV-B viruses. However, scattered nucleotide differences exist between enFeLV env elements and corresponding sequences of exogenous FeLV-B isolates. To address this disparity, we examined recombinant FeLV (rFeLV) viruses obtained from three experimentally-induced feline thymic tumors, along with rFeLVs derived from one naturally-occurring thymic tumor. Two of the three experimental cats were challenged with a FeLV-A/Rickard preparation, while one cat received this FeLV-A along with a mixture of in vitro-generated rFeLVs. The FeLV-A/Rickard preparation employed in this study was shown to be free of detectable rFeLVs since no recombinant products were observed in this preparation following nested PCR analyses. For each of the four tumor DNAs, nucleotide sequence analysis was performed on multiple clones of rFeLV-specific PCR products derived from the surface glycoprotein (SU) portion of the recombinant proviral env gene. Relative to the parental enFeLV sequence used to generate the rFeLVs, a total of 19 nucleotide differences were found scattered within the SU region of the env gene in these in vivo-derived rFeLV clones. Most interestingly, this set of 19 differences led to complete sequence identity with natural FeLV-B isolates. Our results indicate these differences are present early in the in vivo evolution of recombinant viruses, suggesting that rFeLVs harboring these differences are strongly selected. We also present evidence indicating an in vivo selection pattern exists for specific recombinant species containing relatively greater amounts of enFeLV-derived SU sequence. This in vivo selection process appears to be gradual, occurring over the infection timecourse, yielding rFeLV species which have recombination structural motifs similar to those seen in natural FeLV-B isolates.
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Affiliation(s)
- M K Bechtel
- Department of Biochemistry and Molecular Biology, University of Southern California School of Medicine, Los Angeles 90033, USA
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34
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Abstract
Certain isolates of the oncoretrovirus feline leukemia virus (FeLV) are strongly cytopathic for hemolymphatic cells. A major cytopathicity determinant is encoded by the SU envelope glucoprotein gp70. Isolates with subgroup C SU gp70 genes specifically induce apoptosis in hemolymphatic cells but not fibroblasts. In vitro exposure of feline T-cells to FeLV-C leads first to productive viral replication, next to virus-induced cell agglutination, and lastly to apogenesis. This in vitro phenomenon may explain the severe progressive thymic atrophy and erythroid aplasia which follow viremic FeLV-C infection in vivo. Inappropriate apoptosis induction has also been hypothesized to explain the severe thymico-lymphoid atrophy and progressive immune deterioration associated with isolates of FeLV containing variant envelope genes. The influence of envelope hypervariability (variable regions 1 [Vr1] and 5 [Vr5] on virus tropism, viremia induction, neutralizing antibody development and cytopathicity is discussed. Certain potentially cytopathic elements in FeLV SU gp70 Vr5 may derive from replication-defective, poorly expressed, endogenous FeLVs. Other more highly conserved regions in FeLV TM envelope p15E may also influence apoptosis induction.
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Affiliation(s)
- J L Rojko
- Department of Veterinary Pathobiology, Ohio State University, Columbus 43210, USA
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35
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Abstract
Infection remains the major cause of morbidity and mortality following the shock phase in the burn patient. Measures to reduce the risk of wound infection and subsequent sepsis include early excision where possible, and the use of topical antimicrobial creams such as silver sulphadiazine. Studies from the USA and Europe suggest the addition of cerium nitrate to this commonly used agent may improve its efficacy. We present the findings of a pilot study which investigated the action of a commercial preparation of cerium nitrate/silver sulphadiazine mixture (Flammacerium, Duphar B. V. Holland) on 20 patients considered unsuitable for surgery. There were no episodes of cellulitis or septicaemia. Flammacerium was noted to produce an adherent eschar that was easy to shave and which received split skin grafts well.
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Affiliation(s)
- D A Ross
- South-West Thames Regional Burns Unit, Queen Mary's University Hospital, London, UK
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