1
|
Chen LR, Xiao XZ, Yu L, Chu HJ, Duan HL. Texture evolution and mechanical behaviour of irradiated face-centred cubic metals. Proc Math Phys Eng Sci 2018; 474:20170604. [PMID: 29507510 DOI: 10.1098/rspa.2017.0604] [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] [Received: 09/06/2017] [Accepted: 01/26/2018] [Indexed: 11/12/2022] Open
Abstract
A physically based theoretical model is proposed to investigate the mechanical behaviour and crystallographic texture evolution of irradiated face-centred cubic metals. This model is capable of capturing the main features of irradiated polycrystalline materials including irradiation hardening, post-yield softening and plasticity localization. Numerical results show a good agreement with experimental data for both unirradiated and irradiated stress-strain relationships. The study of crystallographic texture reveals that the initial randomly distributed texture of unirradiated metals under tensile loading can evolve into a mixture of [111] and [100] textures. Regarding the irradiated case, crystallographic texture develops in a different way, and an extra part of [110] texture evolves into [100] and [111] textures. Thus, [100] and [111] textures become dominant more quickly compared with those of the unirradiated case for the reason that [100] and [111]-oriented crystals have higher strength, and their plastic deformation behaviours are more active than other oriented crystals. It can be concluded that irradiation-induced defects can affect both the mechanical behaviour and texture evolution of metals, both of which are closely related to irradiation hardening.
Collapse
Affiliation(s)
- L R Chen
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China.,CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China
| | - X Z Xiao
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China.,CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China.,Department of Mechanics, School of Civil Engineering, Central South University, Changsha 410075, People's Republic of China
| | - L Yu
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China
| | - H J Chu
- Department of Mechanics and Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200444, People's Republic of China.,Shanghai Key Laboratory of Mechanics in Energy Engineering, Shanghai University, Shanghai 200072, People's Republic of China
| | - H L Duan
- State Key Laboratory for Turbulence and Complex Systems, Department of Mechanics and Engineering Science, BIC-ESAT, College of Engineering, Peking University, Beijing 100871, People's Republic of China.,CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China
| |
Collapse
|
2
|
Abstract
In this paper, a self-consistent plasticity theory is proposed to model the mechanical behaviours of irradiated face-centred cubic nanocrystalline metals. At the grain level, a tensorial crystal model with both irradiation and grain size effects is applied for the grain interior (GI), whereas both grain boundary (GB) sliding with irradiation effect and GB diffusion are considered in modelling the behaviours of GBs. The elastic-viscoplastic self-consistent method with considering grain size distribution is developed to transit the microscopic behaviour of individual grains to the macroscopic properties of nanocrystals (NCs). The proposed theory is applied to model the mechanical properties of irradiated NC copper, and the feasibility and efficiency have been validated by comparing with experimental data. Numerical results show that: (i) irradiation-induced defects can lead to irradiation hardening in the GIs, but the hardening effect decreases with the grain size due to the increasing absorption of defects by GBs. Meanwhile, the absorbed defects would make the GBs softer than the unirradiated case. (ii) There exists a critical grain size for irradiated NC metals, which separates the grain size into the irradiation hardening dominant region (above the critical size) and irradiation softening dominant region (below the critical size). (iii) The distribution of grain size has a significant influence on the mechanical behaviours of both irradiated and unirradiated NCs. The proposed model can offer a valid theoretical foundation to study the irradiation effect on NC materials.
Collapse
Affiliation(s)
- X Z Xiao
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, People's Republic of China; CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China
| | - D K Song
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering , Peking University , Beijing 100871, People's Republic of China
| | - H J Chu
- Department of Mechanics and Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University, Shanghai 200444, People's Republic of China; State Key Laboratory for Mechanical Behavior of Materials, Xi'an 710049, People's Republic of China
| | - J M Xue
- CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China; State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871, People's Republic of China
| | - H L Duan
- State Key Laboratory for Turbulence and Complex System, Department of Mechanics and Engineering Science, College of Engineering, Peking University, Beijing 100871, People's Republic of China; CAPT, HEDPS and IFSA Collaborative Innovation Center of MoE, Peking University, Beijing 100871, People's Republic of China
| |
Collapse
|
3
|
Zhang D, Liu XH, Li XY, Cao J, Chu HJ, Li K. Ultrastructural investigation of antennae in three cutaneous myiasis flies: Melophagus ovinus, Hippobosca equina, and Hippobosca longipennis (Diptera: Hippoboscidae). Parasitol Res 2015; 114:1887-96. [PMID: 25707367 DOI: 10.1007/s00436-015-4376-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 02/04/2015] [Indexed: 11/28/2022]
Abstract
Melophagus ovinus (Linnaeus 1758), Hippobosca equina Linnaeus, 1758, and Hippobosca longipennis Fabricius, 1805 (Diptera: Hippoboscidae) are economically and medically important ectoparasites that can act as mechanic vectors of pathogens and cause myiasis in both human and domestic animals. As essential olfactory organs, antennae of these adult hippoboscids were examined using stereoscopic and scanning electron microscopes. General morphology of the antenna is provided in detail, combined with distribution, types, size, and ultrastructures of antennal sensilla. On the antennal funiculus, two types of sensilla are observed, including basiconic sensilla and coeloconic sensilla. Four common characters are shared among the three species: (1) the scape is either obsolete or fused with the fronto-clypeus; (2) branched antennal structures (branched pedicellar microtrichiae and branched arista with only one segment) are detected; (3) the enlarged antennal pedicel completely envelops the antennal funiculus; and (4) less types of sensilla on funiculus. Disparity and diversity of the antennal and sensory structures are analyzed from the phylogenetic and functional perspective. We suggest that hippoboscids are potential model for the study of the function of coeloconic sensilla in Calyptratae.
Collapse
Affiliation(s)
- D Zhang
- Key Laboratory of Non-Invasive Research Technology for Endangered Species, School of Nature Conservation, Beijing Forestry University, Beijing, China,
| | | | | | | | | | | |
Collapse
|
4
|
Nogueira FS, Moreira MAB, Borja-Cabrera GP, Santos FN, Menz I, Parra LE, Xu Z, Chu HJ, Palatnik-de-Sousa CB, Luvizotto MCR. Leishmune vaccine blocks the transmission of canine visceral leishmaniasis: absence of Leishmania parasites in blood, skin and lymph nodes of vaccinated exposed dogs. Vaccine 2006; 23:4805-10. [PMID: 16011864 DOI: 10.1016/j.vaccine.2005.05.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2005] [Accepted: 05/16/2005] [Indexed: 10/25/2022]
Abstract
Leishmune vaccine is the first licensed vaccine against canine visceral leishmaniasis. It contains the Fucose-Mannose-ligand (FML) antigen of Leishmania donovani. The potential Leishmune vaccine effect on the interruption of the transmission of the disease, was assayed by monitoring, in untreated (n=40) and vaccinated dogs (n=32) of a Brazilian epidemic area: the kala-azar clinical signs, the FML-seropositivity and the Leishmania parasite evidence by immunohistochemistry of skin and PCR for Leishmanial DNA of lymph node and blood samples. On month 11 after vaccination, untreated controls showed: 25% of symptomatic cases, 50% of FML-seropositivity, 56.7% of lymph node PCR, 15.7% of blood PCR and 25% of immunohistochemical positive reactions. The Leishmune-vaccinated dogs showed 100% of seropositivity to FML and a complete absence of clinical signs and of parasites (0%) in skin, lymph node and blood PCR samples (p<0.01). The positivity in FML-ELISA in untreated dogs significantly correlates with the PCR in lymph node samples (p<0.001) and with the increase in number of symptoms (p=0.006) being strong markers of infectiousness. The absence of symptoms and of evidence of Leishmania DNA and parasites in Leishmune-vaccinated animals indicates the non-infectious condition of the Leishmune-vaccinated dogs.
Collapse
Affiliation(s)
- F S Nogueira
- Faculdade de Medicina Veterinária e Zootecnia, Universidade Estadual Paulista "Júlio de Mesquita Filho", UNESP-Botucatu Distrito Rubião Jr. s/n Botucatu SP CEP 18600-000, Brazil
| | | | | | | | | | | | | | | | | | | |
Collapse
|
5
|
Saville WJA, Sofaly CD, Reed SM, Dubey JP, Oglesbee MJ, Lacombe VA, Keene RO, Gugisberg KM, Swensen SW, Shipley RD, Chiang YW, Chu HJ, Ng T. An equine protozoal myeloencephalitis challenge model testing a second transport after inoculation with Sarcocystis neurona sporocysts. J Parasitol 2005; 90:1406-10. [PMID: 15715237 DOI: 10.1645/ge-128r] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [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: 11/10/2022] Open
Abstract
Previous challenge studies performed at Ohio State University involved a transport-stress model where the study animals were dosed with Sarcocystis neurona sporocysts on the day of arrival. This study was to test a second transportation of horses after oral inoculation with S. neurona sporocysts. Horses were assigned randomly to groups: group 1, transported 4 days after inoculation (DAI); group 2, at 11 DAI; group 3, at 18 DAI; and group 4, horses were not transported a second time (controls). An overall neurologic score was determined on the basis of a standard numbering system used by veterinarians. All scores are out of 5, which is the most severely affected animal. The mean score for the group 1 horses was 2.42; group 2 horses was 2.5; group 3 horses was 2.75; and group 4 horses was 3.25. Because the group 4 horses did not have a second transport, they were compared with all other groups. Statistically different scores were present between group 4 and groups 1 and 2. There was no difference in the time of seroconversion between groups. There was a difference between the time of onset of first clinical signs between groups 1 and 4. This difference was likely because of the different examination days. Differences in housing and handling were likely the reason for the differences in severity of clinical signs. This model results in consistent, significant clinical signs in all horses at approximately the same time period after inoculation but was most severe in horses that did not experience a second transport.
Collapse
Affiliation(s)
- W J A Saville
- Department of Veterinary Preventive Medicine, College of Veterinary Medicine, The Ohio State University, Columbus, Ohio 43210-1092, USA.
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
6
|
Carlson MM, Chiang YW, Chu HJ. Conditional licensing of veterinary biologicals in the United States: a major manufacturer's perspective. Dev Biol (Basel) 2004; 117:97-103. [PMID: 15597624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Affiliation(s)
- M M Carlson
- Fort Dodge Animal Health, Fort Dodge, Iowa 50501, USA.
| | | | | |
Collapse
|
7
|
Ng T, Hathaway D, Jennings N, Champ D, Chiang YW, Chu HJ. Equine vaccine for West Nile virus. Dev Biol (Basel) 2003; 114:221-7. [PMID: 14677692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
To meet the urgent need of controlling West Nile virus (WNV) infection in the equine population, we have developed a killed WNV vaccine. A dose titration study in horses was first conducted to evaluate serum neutralization antibody responses against WNV in these animals. Horses were vaccinated intramuscularly twice with the test vaccine at low, medium and high dose, three weeks apart. Serum samples were collected periodically and were measured for serum neutralizing antibody using a plaque reduction neutralization test. Significant increases in serum neutralizing antibody were detected in all three dosage groups 14 days post the second vaccination. Twelve months after the second vaccination, horses vaccinated with the medium dose of WNV vaccine and non-vaccinated control horses were experimentally challenged with WNV. Nine out of 11 (81.8%) controls developed viraemia after challenge while only one out of 19 (5.3%) vaccinates had transient viraemia, representing a 94% preventable fraction. In a separate study, the safety of the killed WNV vaccine was demonstrated under field conditions. A total of 648 horses, including 32 pregnant mares, were enrolled in the study. During the two weeks post vaccination period, no local or systemic adverse reactions were observed following 96% of the vaccinations administered while mild, transient injection site reactions were noted in a small number of horses. These results indicate that the killed WNV vaccine developed by Fort Dodge Animal Health is safe and efficacious.
Collapse
Affiliation(s)
- T Ng
- Biological Research and Development, Fort Dodge Animal Health, Fort Dodge, Iowa 50501, USA.
| | | | | | | | | | | |
Collapse
|
8
|
Chang YF, Novosel V, Chang CF, Summers BA, Ma DP, Chiang YW, Acree WM, Chu HJ, Shin S, Lein DH. Experimental induction of chronic borreliosis in adult dogs exposed to Borrelia burgdorferi-infected ticks and treated with dexamethasone. Am J Vet Res 2001; 62:1104-12. [PMID: 11453487 DOI: 10.2460/ajvr.2001.62.1104] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [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: 11/20/2022]
Abstract
OBJECTIVE To develop a method to experimentally induce Borrelia burgdorferi infection in young adult dogs. ANIMALS 22 healthy Beagles. PROCEDURE All dogs were verified to be free of borreliosis. Twenty 6-month-old dogs were exposed to Borrelia burgdorferi-infected adult ticks and treated with dexamethasone for 5 consecutive days. Two dogs not exposed to ticks were treated with dexamethasone and served as negative-control dogs. Clinical signs, results of microbial culture and polymerase chain reaction (PCR) testing, immunologic responses, and gross and histologic lesions were evaluated 9 months after tick exposure. RESULTS Predominant clinical signs were episodic pyrexia and lameness in 12 of 20 dogs. Infection with B burgdorferi was detected in microbial cultures of skin biopsy specimens and various tissues obtained during necropsy in 19 of 20 dogs and in all 20 dogs by use of a PCR assay. All 20 exposed dogs seroconverted and developed chronic nonsuppurative arthritis. Three dogs also developed mild focal meningitis, 1 dog developed mild focal encephalitis, and 18 dogs developed perineuritis or rare neuritis. Control dogs were seronegative, had negative results for microbial culture and PCR testing, and did not develop lesions. CONCLUSIONS AND CLINICAL RELEVANCE Use of this technique successfully induced borreliosis in young dogs. Dogs with experimentally induced borreliosis may be useful in evaluating vaccines, chemotherapeutic agents, and the pathogenesis of borreliosis-induced arthritis.
Collapse
Affiliation(s)
- Y F Chang
- Department of Population Medicine, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Chowdhury SI, Ross CS, Lee BJ, Hall V, Chu HJ. Construction and characterization of a glycoprotein E gene-deleted bovine herpesvirus type 1 recombinant. Am J Vet Res 1999; 60:227-32. [PMID: 10048557] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/11/2023]
Abstract
OBJECTIVE To construct and characterize a recombinant glycoprotein (g)E gene-deleted bovine herpesvirus (BHV) type 1 (BHV-1). PROCEDURE The BHV-1 gEgene-coding region and the flanking upstream and downstream sequences were cloned. The aforementioned cloned DNA was digested with suitable enzymes to release the amino terminal two thirds of that region, and was ligated to the beta-galactosidase (beta-gal) gene. The resulting plasmid DNA was cotransfected with DNA from full-length, wild-type (WT), BHV-1 Cooper strain of the virus. Recombinant viruses expressing beta-gal (blue plaques) were plaque purified and assayed further by blot hybridization for genetic characterization and by immunoblotting for reactivity against BHV-1 gE peptide-specific rabbit polyclonal antibody. One recombinant virus, gEdelta3.1IBR, was characterized in vitro and in vivo. The ability of the recombinant virus to induce BHV-1 neutralizing antibodies in infected calves was investigated by plaque-reduction tests. RESULTS AND CONCLUSIONS The gEdelta3.1IBR virus contained a deletion in the viral gE gene-coding sequences where a stable chimeric reporter (beta-gal) gene was inserted. One-step growth kinetics and virus yield of the recombinant and parent viruses were similar, but early after infection, the recombinant virus yield was comparatively less. After intranasal inoculation, the recombinant gEdelta3.1IBR virus replicated in the upper respiratory tract of calves, but the amount of progeny viruses produced was hundredsfold reduced, and duration of virus shedding was shorter. Results of in vivo calf experiments and serum neutralization tests indicated that deleting the gE gene has little effect on inducing neutralizing antibodies against BHV-1, but is sufficient to reduce BHV-1 virulence in calves.
Collapse
Affiliation(s)
- S I Chowdhury
- Department of Diagnostic Medicine/Pathobiology, College of Veterinary Medicine, Kansas State University, Manhattan 66506, USA
| | | | | | | | | |
Collapse
|
10
|
Powell DG, Dwyer RM, Traub-Dargatz JL, Fulker RH, Whalen JW, Srinivasappa J, Acree WM, Chu HJ. Field study of the safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine. J Am Vet Med Assoc 1997; 211:193-8. [PMID: 9227750] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
OBJECTIVE To determine safety, immunogenicity, and efficacy of an inactivated equine rotavirus vaccine. DESIGN Prospective randomized controlled trial. ANIMALS 316 pregnant Thoroughbred mares during the first year of the study and 311 during the second year. PROCEDURE During the first year, mares received 3 doses of vaccine or placebo, IM, at 8, 9, and 10 months of gestation. Serum neutralizing antibody titers were measured before vaccination and 1 and 35 days after foaling. Antibody titers were measured in foals 1, 7, 35, 60, 90, and 120 days after birth. During the second year, mares that had been vaccinated the previous year received a single booster dose of vaccine approximately 1 month prior to parturition. Mares that had received the placebo the previous year and mares new to the study received 3 doses of vaccine or placebo. Serum neutralizing antibody titers were measured in samples taken from mares approximately 1 day after foaling and from foals approximately 1 and 60 days after birth. RESULTS Adverse reactions were not observed. Antibody titers were significantly increased at the time of foaling and 35 days after foaling in vaccinated, compared with control, mares and for 90 days after birth in foals born to vaccinated, compared with foals born to control, mares. Incidence of rotaviral diarrhea was lower in foals born to vaccinated, compared with foals born to control, mares, but the difference was not significant. CLINICAL IMPLICATIONS Results suggest that the equine rotavirus vaccine is safe and immunogenic and that reasonable efficacy under field conditions can be expected.
Collapse
Affiliation(s)
- D G Powell
- Department of Veterinary Science, College of Agriculture, University of Kentucky, Lexington 40546, USA
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Abstract
An inactivated whole-virus FeLV vaccine, developed from a molecularly cloned FeLV isolate (FeLV-61E-A), was assessed for its ability to protect cats against homologous and heterologous virulent viral challenge. The fractions of cats that resisted the induction of persistent viremia after FeLV challenge were as follows: FeLV-61E-A vaccine, 95%; adjuvant controls, 26%; and established commercial control FeLV vaccine, 35%. The prechallenge mean neutralizing antibody titers for each group were as follows: FeLV-61E-A vaccine, 1:43; adjuvant controls, < 1:8; and commercial control FeLV vaccine, 1:12. The prototype FeLV-61E-A vaccine was developed commercially for immunization of pet cats by substitution of a proprietary adjuvant and development of stable, high antigen production cell lines. This vaccine (Fel-O-Vax) has been studied extensively, alone and in multivalent combination with other feline virus vaccines, in seven efficacy trials involving a total of 150 immunized cats. These studies yielded an FeLV-resistant fraction of 87% in vaccinated cats as compared with 8% in adjuvant controls. The duration of immunity induced by an FeLV-61E-A commercial vaccine (Fel-O-Vax-LvK IV) was also assessed. One year after vaccination, 100% of challenged vaccinated cats and none of challenged controls resisted induction of persistent viremia. The results of these studies demonstrate that an inactivated FeLV vaccine prepared from a molecularly cloned subgroup A FeLV produces a high level of protective immunity against heterologous and homologous FeLV infection. This vaccine-induced immunity is durable for at least 1 year without intervening booster immunization or exposure to virus.
Collapse
Affiliation(s)
- E A Hoover
- Department of Pathology, Colorado State University, Fort Collins 80523, USA
| | | | | | | |
Collapse
|
12
|
Hoover EA, Mullins JI, Chu HJ, Wasmoen TL. Development and testing of an inactivated feline leukemia virus vaccine. Semin Vet Med Surg Small Anim 1995; 10:238-43. [PMID: 8820598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We assessed an inactivated whole virus feline leukemia virus (FeLV) vaccine developed from a molecularly cloned feline leukemia virus isolate (FeLV-61E-A) for its ability to protect cats against homologous and heterologous virulent virus challenge. The fractions of cats that resisted the induction of persistent viremia after FeLV challenge were the following: (1) FeLV-61E-A vaccine, 95%; (2) adjuvant controls, 26%; and (3) established commercial control FeLV vaccine, 35%. The pre-challenge mean neutralizing antibody titers for each group were (1) FeLV-61E-A vaccine, 1:43; (2) adjuvant controls, <1:8; and (3) established commercial control FeLV vaccine: 1:12. The commercial version of the prototype FeLV-61E-A vaccine (Fel-O-Vax, Fort Dodge Laboratories, Fort Dodge, IA) was developed through use of a proprietary adjuvant and a stable high antigen production cell lines. The efficacy and duration of immunity produced by Fel-O-Vax was studied alone and in multivalent combination with other feline virus vaccines in seven subsequent efficacy trials conducted in over 150 immunized cats. The overall FeLV-resistant fraction in these trials was 87% in vaccinated cats versus 8% in adjuvant controls. The duration of protective immunity induced by the multivalent Fel-O-Vax-LvK IV at 1 year postvaccination was 100% in challenged vaccinees versus 0% in challenged controls. The results of these studies show that an inactivated FeLV vaccine prepared from a molecularly cloned subgroup A FeLV can produce high level protective immunity against FeLV infection. This immunity is durable for at least 1 year without intervening booster immunization or virus exposure.
Collapse
Affiliation(s)
- E A Hoover
- Department of Pathology, Colorado State University, Fort Collins 80523, USA
| | | | | | | |
Collapse
|
13
|
Fulker R, Wasmoen T, Atchison R, Chu HJ, Acree W. Efficacy of an inactivated vaccine against clinical disease caused by canine coronavirus. Adv Exp Med Biol 1995; 380:229-34. [PMID: 8830484 DOI: 10.1007/978-1-4615-1899-0_37] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Canine Coronavirus (CCV) is a causative agent of diarrhea in dogs. The reproduction of severe clinical disease with experimental CCV infection has been difficult. We have recently developed a CCV challenge model which reproduced clinical signs of disease in susceptible dogs. The following study was designed to determine whether immunization with an inactivated CCV vaccine would protect dogs from clinical disease induced using this model. Dogs (n = 13) were vaccinated with an inactivated CCV vaccine. Vaccinates and controls (n = 5) were orally inoculated with virulent CCV virus and treated with dexamethasone on days 0, 2, 4, and 6 after virus challenge. Control dogs developed clinical signs including diarrhea, dehydration, anorexia, depression, and nasal and ocular discharge. Diarrhea was noted in 80% of the controls and 60% progressed to a severe watery or bloody diarrhea that persisted for multiple days. Conversely, only 2/13 (15%) vaccinates developed mild diarrhea and none developed bloody diarrhea. The control dogs averaged 10.8 days of diarrhea compared to 1.4 days for vaccinates over the 21 day observation period. In addition to reduced clinical signs, the number of days of virus shedding and the level of CCV in feces was different for controls (100% shed virus) and vaccinates (38% shed virus). This study demonstrates that vaccination with an inactivated CCV vaccine can significantly reduce not only viral replication, but the occurrence of clinical disease following a virulent CCV infection.
Collapse
Affiliation(s)
- R Fulker
- Fort Dodge Laboratories, Iowa, USA
| | | | | | | | | |
Collapse
|
14
|
Wasmoen TL, Kadakia NP, Unfer RC, Fickbohm BL, Cook CP, Chu HJ, Acree WM. Protection of cats from infectious peritonitis by vaccination with a recombinant raccoon poxvirus expressing the nucleocapsid gene of feline infectious peritonitis virus. Adv Exp Med Biol 1995; 380:221-8. [PMID: 8830483 DOI: 10.1007/978-1-4615-1899-0_36] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Feline Infectious Peritonitis Virus (FIPV) is a coronavirus that induces an often fatal, systemic infection in cats. Various vaccines designed to prevent FIPV infection have been shown to exacerbate the disease, probably due to immune enhancement mediated by virus-specific immunoglobulins against the outer envelope (S) protein. An effective vaccine would be one that induces cell-mediated immunity without disease enhancing antibodies. In this report, we describe the use of a recombinant raccoon poxvirus that expresses the gene encoding the nucleocapsid protein of FIPV (rRCNV-FIPV N) as an effective vaccine against FIPV-induced disease. Cats were parenterally or orally vaccinated twice, three weeks apart. Cats were then orally challenged with Feline Enteric Coronavirus (FECV), which induces a subclinical infection that can cause enhancement of subsequent FIPV infection. Three weeks later, cats were orally challenged with FIPV. The FIPV challenge induced a fatal infection in 4/5 (80%) of the controls. On the other hand, all five cats vaccinated subcutaneously with rRCNV-FIPV N showed no signs of disease after challenge with FIPV. Four of the five subcutaneous vaccinates survived an additional FIPV challenge. Vaccination with rRCNV-FIPV N induced serum IgG antibody responses to FIPV nucleocapsid protein, but few, if any, FIPV neutralizing antibodies. In contrast to the controls, protected vaccinates maintained low FIPV serum neutralizing antibody titers after FIPV challenge. This suggests that the protective immune response involves a mechanism other than humoral immunity consisting of FIPV neutralizing antibodies.
Collapse
|
15
|
Chu HJ. Article on Borrelia burgdorferi revisited. J Am Vet Med Assoc 1993; 203:783. [PMID: 8226228] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
|
16
|
Wasmoen T, Armiger-Luhman S, Egan C, Hall V, Chu HJ, Chavez L, Acree W. Transmission of feline immunodeficiency virus from infected queens to kittens. Vet Immunol Immunopathol 1992; 35:83-93. [PMID: 1337404 DOI: 10.1016/0165-2427(92)90123-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [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: 12/26/2022]
Abstract
This study demonstrates the transmission of feline immunodeficiency virus (FIV) from infected queens to kittens in two separate litters. Queen 1 was infected by intravenous administration of FIV at 22 days prior to parturition. Two out of three kittens from the litter were found to be viremic at 10 weeks of age as detected by culture isolation and polymerase chain reaction detection of FIV DNA in peripheral blood mononuclear leukocytes. The third kitten remained aviremic through 40 weeks of age. Queen 2 was infected by subcutaneous administration of FIV 2 days prior to parturition. This litter also had two out of three kittens infected with FIV; however, viremia was not detected in one of the kittens until 21 weeks of age. Culture isolation was found to be superior to polymerase chain reaction for the early detection of FIV, and viremia was found to precede seroconversion by up to 4 weeks. Although all infected kittens have remained healthy, depressed CD4:CD8 lymphocyte ratios suggest that clinical disease may develop. This study suggests that FIV infection in cats may be a useful model system for the study of HIV transmission from mothers to infants.
Collapse
Affiliation(s)
- T Wasmoen
- Department of Biological Research and Development, Fort Dodge Laboratories, IA 50501
| | | | | | | | | | | | | |
Collapse
|
17
|
Kvasnicka WG, Hanks D, Huang JC, Hall MR, Sandblom D, Chu HJ, Chavez L, Acree WM. Clinical evaluation of the efficacy of inoculating cattle with a vaccine containing Tritrichomonas foetus. Am J Vet Res 1992; 53:2023-7. [PMID: 1466496] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
To test the efficacy of a polyvalent Tritrichomonas foetus vaccine, 130 nulliparous heifers were randomly assigned to either receive the test T foetus vaccine or to serve as nonvaccinated controls. The polyvalent test vaccine consisted of a Campylobacter fetus/Leptospira canicola-grippotyphosa-hardjo-icterohaemorrhagiae-pamona bacterine containing 5 x 10(7) killed T foetus/dose. The polyvalent control vaccine consisted of the aforementioned formulation without T foetus. Heifers were administered 2 doses of control or experimental vaccine at 3-week intervals. Heifers were bred to T foetus-infected bulls and their conception and pregnancy rates were determined throughout gestation. In addition, serum samples were analyzed to determine induced concentrations of antitrichomonal antibodies and vaginal secretions were sampled to determine T foetus infection rates in control and vaccinated animals. One week after each of the 15-day breeding periods, 60% (6 of 10) of tested vaccinates and 80% (8 of 10) of tested control animals were T foetus culture-positive. The mean duration of infection of vaccinates was 3.8 weeks (+/- 7.5 days), compared with 5.4 weeks (+/- 7.5 days) of infection for control heifers. All vaccinates developed increased immunofluorescence and serum neutralizing antibody titers following the first immunization, and had additional increases of at least fourfold in response to the second injection. In contrast, no consistent increase in immunofluorescence or serum neutralizing antibodies was observed in control animals. Conception rates were 89.2% for vaccinates and 85.9% for control animals 30 days after breeding and 80 to 90% of these remained pregnant 60 days after breeding.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- W G Kvasnicka
- School of Veterinary Medicine, College of Agriculture, University of Nevada, Reno 98557
| | | | | | | | | | | | | | | |
Collapse
|
18
|
Wasmoen TL, Sebring RW, Blumer BM, Chavez LG, Chu HJ, Acree WM. Examination of Koch's postulates for Borrelia burgdorferi as the causative agent of limb/joint dysfunction in dogs with borreliosis. J Am Vet Med Assoc 1992; 201:412-8. [PMID: 1307866] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Borrelia burgdorferi has been implicated as the causative agent of borreliosis in dogs, which is characteristically a limb/joint disorder, but can be associated with multiple-organ dysfunction. Attempts to reproduce this disease by inoculating dogs with B burgdorferi have not been successful. In the study of this report, B burgdorferi from Ixodes dammini ticks was used to induce signs of limb/joint dysfunction, fever, anorexia, depression, and systemic infection in dogs. A pure culture of this bacterium from the blood of an infected dog has been used to fulfill Koch's postulates for B burgdorferi as the causative agent of limb/joint dysfunction associated with borreliosis in dogs.
Collapse
|
19
|
Chu HJ, Chavez LG, Blumer BM, Sebring RW, Wasmoen TL, Acree WM. Immunogenicity and efficacy study of a commercial Borrelia burgdorferi bacterin. J Am Vet Med Assoc 1992; 201:403-11. [PMID: 1506244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The immunogenicity and efficacy of a commercial Borrelia burgdorferi bacterin was evaluated for stimulation of the host immune response and protection against clinical disease associated with experimentally induced borreliosis in dogs. A total of 30 vaccinated and 24 control dogs were used in 3 separate studies. The vaccine was given IM as two 1-ml doses separated by a 3-week interval. Two weeks or 5 months following the last vaccination, the dogs were challenge inoculated with 7 daily doses of a virulent preparation of a B burgdorferi field isolate through intraperitoneal, subcutaneous, and intradermal routes with or without glucocorticoid administration at the same time. The development of B burgdorferi spirochetemia and clinical disease in the dogs after challenge exposure was studied. Serum samples were obtained from the dogs at various times during the study for serum neutralizing antibody determination and protein immunoblot antibody assay against various geographic isolates of B burgdorferi. Challenge exposure induced limb/joint disorder, fever, anorexia, signs of depression, and B burgdorferi spirochetemia in the nonvaccinated control dogs. The vaccine was found to elicit cross-reactive serum neutralizing and protein immunoblot antibody responses in dogs to various isolates of B burgdorferi and to protect the vaccinated dogs against experimentally induced borreliosis.
Collapse
Affiliation(s)
- H J Chu
- Fort Dodge Laboratories, IA 50501
| | | | | | | | | | | |
Collapse
|
20
|
Sebring RW, Chu HJ, Chavez LG, Sandblom DS, Hustead DR, Dale B, Wolf D, Acree WM. Feline leukemia virus vaccine development. J Am Vet Med Assoc 1991; 199:1413-9. [PMID: 1666094] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Affiliation(s)
- R W Sebring
- Biological Research and Development, Fort Dodge Laboratories, IA 50501
| | | | | | | | | | | | | | | |
Collapse
|
21
|
Legendre AM, Hawks DM, Sebring R, Rohrbach B, Chavez L, Chu HJ, Acree WM. Comparison of the efficacy of three commercial feline leukemia virus vaccines in a natural challenge exposure. J Am Vet Med Assoc 1991; 199:1456-62. [PMID: 1666103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Forty-seven kittens were exposed for 31 weeks to 12 FeLV-positive carrier cats. The carrier cats were infected with 2 laboratory strains of FeLV and at least 2 strains of street virus. Eleven nonvaccinated control kittens and 12 vaccinated kittens were allotted to 3 groups. After 31 weeks of exposure, the following kittens were persistently blood FeLV positive by ELISA and immunofluorescence antibody (IFA) testing: 7 of the 11 control kittens, 0 of 12 kittens inoculated with vaccine A, 5 of 12 kittens inoculated with vaccine B, and 6 of 12 kittens inoculated with vaccine C. Only the kittens inoculated with vaccine A were significantly (P less than 0.05) different from the control group. After 23 weeks of exposure, culture was done to identify FeLV in the bone marrow of the kittens. Feline leukemia virus was isolated from the bone marrow of 9 of 11 control kittens. Virus was isolated from the bone marrow of 5 of 12 kittens inoculated with vaccine A, 11 of 12 kittens inoculated with vaccine B, and 10 of 12 kittens inoculated with vaccine C. Of the 17 cats that had FeLV isolated only from culture of bone marrow (negative results of blood virus isolation, ELISA, and IFA testing), 13 eliminated the virus from the bone marrow by week 31 of exposure. After 31 weeks of exposure, FeLV was isolated from the bone marrow of 8 of 11 control kittens, 0 of 12 kittens inoculated with vaccine A, 7 of 12 kittens inoculated with vaccine B, and 7 of 12 kittens inoculated with vaccine C.
Collapse
Affiliation(s)
- A M Legendre
- Department of Urban Practice, College of Veterinary Medicine, University of Tennessee, Knoxville 37901
| | | | | | | | | | | | | |
Collapse
|
22
|
Hawks DM, Legendre AM, Rohrbach BW, Sebring R, Chavez L, Chu HJ, Acree WM. Antibody response of kittens after vaccination followed by exposure to feline leukemia virus-infected cats. J Am Vet Med Assoc 1991; 199:1463-9. [PMID: 1666104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Protein (western) blot analysis and virus-neutralization assay were used to evaluate the antibody response of specific-pathogen-free kittens to FeLV vaccination and followed by natural exposure. Several kittens had barely detectable reactions to specific FeLV antigens prior to vaccination or exposure. Correlation was not found between protection against persistent viremia and antibody response after vaccination as measured by western blot analysis or virus neutralization assay. A statistically significant (P less than 0.01) difference in the antibody response against p27 antigen after natural exposure to FeLV was observed between persistently viremic kittens and transiently viremic or aviremic kittens. Measurable (P less than 0.05) virus neutralizing antibody titer after FeLV exposure was found only in a small number of kittens that were protected against persistent viremia. Lack of association between humoral response and vaccination-induced protection against persistent FeLV infection suggests an important role for cell-mediated immunity in such protection.
Collapse
Affiliation(s)
- D M Hawks
- Department of Urban Practice, College of Veterinary Medicine, University of Tennessee, Knoxville 37901
| | | | | | | | | | | | | |
Collapse
|
23
|
Chu HJ, Sawyer MM, Anderson CA, Higgins RJ, Zee YC. Enzyme-linked immunosorbent assay for the detection of antibodies to bovine virus diarrhea virus in sera from border disease virus-infected sheep. Can J Vet Res 1987; 51:281-3. [PMID: 3038292 PMCID: PMC1255318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
An enzyme-linked immunosorbent assay (ELISA) was established for the rapid detection of specific antibodies against the causative agent of border disease in ovine sera. Polyethylene-glycol concentrated, equilibrium density gradient purified bovine virus diarrhea virus was used as test antigen. The optimal amount of antigen was 0.5 microgram/well, and the optimal concentration of conjugate was at 1/4,000 dilution. A total of 20 ovine serum samples, which had been collected from animals with or without border disease, were compared by ELISA and serum neutralization test for the detection of border disease-specific antibodies. ELISA was shown to be equally specific but less time-consuming and easier to perform than serum neutralization test. A positive correlation (r = 0.60) between the two tests was found.
Collapse
|
24
|
Chu HJ, Zee YC, Ardans AA, Dai K. Enzyme-linked immunosorbent assay for the detection of antibodies to bovine viral diarrhea virus in bovine sera. Vet Microbiol 1985; 10:325-33. [PMID: 2994278 DOI: 10.1016/0378-1135(85)90003-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A specific and sensitive enzyme-linked immunosorbent assay (ELISA) was established for the detection of antibodies to bovine viral diarrhea virus (BVDV) in bovine sera. Polyethylene-glycol concentrated, equilibrium density gradient purified BVDV was used as test antigen at an optimal amount of 1 microgram/well, whereas the optimal concentration of conjugate was at 1/2000 dilution. The standardized test encountered no non-specific reaction with test sera at a starting dilution of 1/10. A total of 50 bovine serum samples was assayed for the presence of antibodies against BVDV by ELISA and serum neutralization test (SNT). A positive correlation between the 2 tests was found. However, ELISA could be as much as 500-fold more sensitive than SNT in detecting low levels of BVDV antibodies.
Collapse
|
25
|
Chu HJ, Zee YC. Morphology of bovine viral diarrhea virus. Am J Vet Res 1984; 45:845-50. [PMID: 6329046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The morphology of bovine viral diarrhea virus (BVDV) was studied by electron microscopy. The NADL strain of BVDV was plaque purified 3 times, concentrated by polyethylene glycol precipitation, and purified by centrifugation to equilibrium in continuous potassium tartrate density-gradients. The virus was examined by negative-stain electron microscopy in the presence or absence of specific antiserum. The density of BVDV was between 1.101 g/cm3 and 1.174 g/cm3, with the peak at maximum infectivity at 1.122 g/cm3. Oval to pleomorphic viral particles, 120 ( +/- 30) nm in diameter, were enriched in the peak of maximum infectivity. The detailed structure of virions was revealed: a 5- to 7-microns thick unit membrane-like envelope layer with numerous projecting knobs, 4 to 5 nm in diameter, surrounding an interior core-like structure. Viral particles measuring 120 ( +/- 30) nm were found in large aggregates in the presence of specific antiserum.
Collapse
|
26
|
Chu HJ. Bucephalopsis kweiyangensis n. sp. from the Giant Salamander, Megalobatrachus japonicus Temm. in Kweichow, China. J Parasitol 1950. [DOI: 10.2307/3273587] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
27
|
|
28
|
|