RESUMO
Transient endometritis after breeding is necessary for clearance of bacteria and spermatozoa; however, in a subpopulation of mares, the inflammation fails to resolve in a timely fashion. The objective of this study was to describe the uterine inflammatory response in mares susceptible or resistant to persistent breeding-induced endometritis (PBIE) during the first 24 h after induction of uterine inflammation.Twelve mares were classified as susceptible (nZ6) or resistant (nZ6) to PBIE. Mares were inseminated over five estrous cycles and endometrial biopsies were collected at one time point per cycle before (0) and 2, 6, 12, and 24 h after insemination. qPCR analysis for IL1B, IL6, IL8, IFNG, TNF (TNFA), IL10, and IL1RN was performed, and endometrial inflammatory cells were counted for each sample. Relative quantification values reported fold changes in mRNA expression from 0 h values. A general pattern of expression post insemination was observed in both groups of mares. Cytokine mRNA increased at 2 h, peaked between 2 and 12 h, and then decreased.Differences were detected between groups of mares 6 h after challenge; resistant mares had higher mRNA expression of IL6, IL1RN,and IL10 than susceptible mares. Susceptible mares had an increased number of polymorphonuclear neutrophils in the endometrium 2 and 12 h after breeding when compared with resistant mares. These findings describe an inherent difference in the initial immune response to insemination and may help explain the transient nature of inflammation in resistant mares, whereas susceptible mares develop a persistent inflammation.
Assuntos
Cruzamento , Citocinas/metabolismo , Endometriose/veterinária , Endométrio/imunologia , Doenças dos Cavalos/imunologia , Cavalos , Mediadores da Inflamação/metabolismo , Inseminação Artificial/veterinária , Animais , Biópsia/veterinária , Citocinas/genética , Suscetibilidade a Doenças , Endometriose/genética , Endometriose/imunologia , Endometriose/patologia , Endométrio/patologia , Feminino , Regulação da Expressão Gênica , Doenças dos Cavalos/genética , Doenças dos Cavalos/patologia , Inseminação Artificial/efeitos adversos , RNA Mensageiro/metabolismo , Reação em Cadeia da Polimerase em Tempo Real/veterinária , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Fatores de Risco , Fatores de TempoRESUMO
The first objective of this study was to evaluate intrauterine nitric oxide (NO) and endometrial inducible NO synthase (iNOS) in mares susceptible or resistant to persistent breeding-induced endometritis (PBIE) within 24 h after breeding. Mares susceptible (n = 6) or resistant (n = 6) to PBIE were inseminated over five cycles, and uterine secretions and endometrial biopsies were collected before and 2, 6, 12 and 24 h after insemination. Uterine secretions were analysed for NO and biopsies were analyzed for iNOS expression. A second experiment evaluated the effect of treatment with dexamethasone or mycobacterial cell wall extract (MCWE) on uterine NO production and endometrial iNOS mRNA expression. Six susceptible mares were inseminated over three cycles with (i) killed spermatozoa without treatment (control), (ii) killed spermatozoa with 50 mg of dexamethasone IV or (iii) MCWE IV 24 h prior to insemination with killed spermatozoa. Six resistant mares were inseminated with killed spermatozoa as a control. Six hours after breeding, uterine biopsies and secretions were collected and evaluated for NO and iNOS mRNA. In Experiment 1, resistant mares had an increase in iNOS mRNA expression 2 h post-breeding compared to baseline (p = 0.045), 12 h (p = 0.014) and 24 h (p = 0.001). Susceptible mares had higher expression 2 h compared to 6 h (p = 0.046). No differences were observed in mRNA or protein expression of iNOS between resistant and susceptible mares. Resistant mares had a relatively steady amount of total intrauterine NO over 24 h, while susceptible mares had an increase over time, with a significantly higher increase in total NO than resistant mares at 6 (p = 0.04) and 12 h (p = 0.032). In Experiment 2, no differences were observed for iNOS mRNA expression. Susceptible mares had increased NO when compared to resistant mares (p = 0.008) and MCWE decreased NO (p = 0.047).
Assuntos
Suscetibilidade a Doenças/veterinária , Endometrite/veterinária , Doenças dos Cavalos/imunologia , Imunomodulação , Óxido Nítrico/biossíntese , Útero/metabolismo , Animais , Cruzamento , Parede Celular/imunologia , Dexametasona/administração & dosagem , Resistência à Doença , Suscetibilidade a Doenças/imunologia , Endometrite/etiologia , Endometrite/imunologia , Endométrio/enzimologia , Feminino , Doenças dos Cavalos/etiologia , Cavalos/imunologia , Cavalos/metabolismo , Inseminação Artificial/veterinária , Mycobacterium/imunologia , Óxido Nítrico Sintase Tipo II/genética , Óxido Nítrico Sintase Tipo II/metabolismo , Reação em Cadeia da Polimerase/veterinária , RNA Mensageiro/análiseRESUMO
Studies investigating age-related changes in the function of monocytes are currently limited for horses. Thus, the main goal of this study was to determine the effect of aging on monocyte phagocytic capacity and pro-inflammatory cytokine responses to bacterial lipopolysaccharide (LPS). A second goal of this work was to examine the effect of aging on the inflammatory cytokine responses to LPS in a whole blood ex vivo model. Seven healthy young adult (4-6 years of age) and seven healthy senior horses (>20 years of age) were enrolled. Phagocytosis of E. coli, and pro-inflammatory cytokine (TNFα) responses to LPS, were measured in monocytes by flow cytometry. Gene expressions of pro-inflammatory cytokines (TNFα, IL-1ß, IL-6, IL-8, IL-18, CCL-5, CCL-2) were measured in peripheral blood mononuclear cells (PBMCs) and whole blood by RT-qPCR post incubation for 2 h or 6 h with a low (0.01 µg/mL) or a high (1 µg/mL) dose of LPS. Two sets of statistical models were applied to compare the age groups, one adjusted, and one unadjusted for the horses' body condition scores (BCS). The percentage of monocytes that phagocytosed E. coli after 2 h of incubation was significantly lower in senior compared to young adult horses in the BCS-adjusted model. In the senior group, the expression of IL-1ß in 2 h-0.01 µg/mL LPS-stimulated PBMCs was significantly higher than in the young adult group (BCS-adjusted and unadjusted models). In senior horses, expressions of IL-8 and IL-6 in whole blood samples stimulated for 6 h with 0.01 µg/mL LPS and for 2 h with 1 µg/mL LPS, respectively, were significantly lower than in young adult horses (BCS-adjusted models). The results of this study suggest that the phagocytic function of monocytes, as well as their IL-1ß response to LPS may be altered in senior horses. In addition, the whole blood IL-8 and IL-6 gene expression responses to LPS may be insufficient in senior horses. While investigation of the effect of BCS on monocyte functions and whole blood pro-inflammatory LPS-responses was not a major goal of this work, it appears that adiposity may play a role in innate immune cell function, as significant differences between the age groups were often not apparent until the models were adjusted for BCS.
Assuntos
Lipopolissacarídeos , Monócitos , Envelhecimento , Animais , Citocinas , Escherichia coli , Cavalos , Interleucina-6/metabolismo , Interleucina-8/genética , Leucócitos Mononucleares/metabolismo , Lipopolissacarídeos/farmacologia , Fator de Necrose Tumoral alfa/genéticaRESUMO
Stimulation of cultures of murine bone-marrow cells with specific macrophage growth factor (colony-stimulating factor I) resulted in the production of type I interferon. Neutralization of this endogenous interferon by antiserum directed against interferons alpha and beta resulted in a significant enhancement of mononuclear phagocyte proliferation from committed marrow precursors. The effect of the antiserum was lost in cultures depleted of adherent cells, an indication that an adherent regulatory cell (or cells) in the marrow limits mononuclear phagocyte proliferation by producing antiproliferative interferon in response to high levels of specific growth factor.
Assuntos
Fatores Estimuladores de Colônias/farmacologia , Interferon Tipo I/fisiologia , Macrófagos/citologia , Animais , Medula Óssea , Divisão Celular , Células Cultivadas , Células Clonais , Soros Imunes , Interferon Tipo I/biossíntese , Interferon Tipo I/imunologia , Macrófagos/fisiologia , Camundongos , Timidina/metabolismoRESUMO
Haemonchus contortus is one of the major nematode parasites causing substantial economic losses in small ruminant farming worldwide. Recently, effectiveness of anthelmintic treatment has decreased due to an increasing problem of nematode populations that have developed resistance to anthelmintics. Efforts to develop effective vaccines have had limited success. There are certain breeds of sheep that are relatively resistant to the parasite including Gulf Coast Native (Native) sheep. Understanding the protective nature of the immune response that helps these breeds of sheep control infection could enable the development of vaccines to enhance control programs. This experiment was designed to compare the immunological responses of resistant Native versus susceptible Suffolk sheep in order to identify the mechanisms responsible for this resistance. Immune responses were evaluated in naturally infected Native and Suffolk lambs that grazed pasture contaminated predominantly with H. contortus. Ten lambs of each breed grazed together for 42 days. Fecal, blood and serum samples were collected on 0, 2, 4, 7, 10, 14, 21, 28, 35 and 42 days of exposure. Five lambs of each breed were necropsied on day 35 and five on day 42 for nematode recovery and abomasal tissue sample collection. Throughout the course of infection, Native lambs had significantly lower FEC, significantly lower PCV reduction percent, and significantly higher serum IgE after day 14 and increased expression of IL-4 on day 10 post-exposure compared to Suffolk lambs. At both necropsy time points, Native lambs had significantly greater numbers of mucosal mast cells, eosinophils and globule leukocytes in abomasal mucosa than Suffolk lambs. Results indicated that Native lambs had a more pronounced immune response to infection with H. contortus than Suffolk lambs which may be responsible for the observed resistance to infection.
Assuntos
Gastroenteropatias/veterinária , Hemoncose/veterinária , Imunidade Inata/genética , Doenças dos Ovinos/parasitologia , Animais , Gastroenteropatias/genética , Gastroenteropatias/imunologia , Predisposição Genética para Doença , Hemoncose/genética , Hemoncose/imunologia , Haemonchus , Ovinos , Doenças dos Ovinos/genética , Fatores de TempoRESUMO
REASONS FOR PERFORMING STUDY: Three previously described NS1 mutant equine influenza viruses encoding carboxy-terminally truncated NS1 proteins are impaired in their ability to inhibit type I IFN production in vitro and are replication attenuated, and thus are candidates for use as a modified live influenza virus vaccine in the horse. HYPOTHESIS: One or more of these mutant viruses is safe when administered to horses, and recipient horses when challenged with wild-type influenza have reduced physiological and virological correlates of disease. METHODS: Vaccination and challenge studies were done in horses, with measurement of pyrexia, clinical signs, virus shedding and systemic proinflammatory cytokines. RESULTS: Aerosol or intranasal inoculation of horses with the viruses produced no adverse effects. Seronegative horses inoculated with the NS1-73 and NS1-126 viruses, but not the NS1-99 virus, shed detectable virus and generated significant levels of antibodies. Following challenge with wild-type influenza, horses vaccinated with NS1-126 virus did not develop fever (>38.5 degrees C), had significantly fewer clinical signs of illness and significantly reduced quantities of virus excreted for a shorter duration post challenge compared to unvaccinated controls. Mean levels of proinflammatory cytokines IL-1beta and IL-6 were significantly higher in control animals, and were positively correlated with peak viral shedding and pyrexia on Day +2 post challenge. CONCLUSION AND CLINICAL RELEVANCE: These data suggest that the recombinant NS1 viruses are safe and effective as modified live virus vaccines against equine influenza. This type of reverse genetics-based vaccine can be easily updated by exchanging viral surface antigens to combat the problem of antigenic drift in influenza viruses.
Assuntos
Anticorpos Antivirais/sangue , Doenças dos Cavalos/prevenção & controle , Vírus da Influenza A Subtipo H3N8/imunologia , Vacinas contra Influenza/imunologia , Infecções por Orthomyxoviridae/veterinária , Administração Intranasal , Animais , Citocinas/biossíntese , Doenças dos Cavalos/imunologia , Doenças dos Cavalos/virologia , Cavalos , Vacinas contra Influenza/efeitos adversos , Vacinas contra Influenza/genética , Nebulizadores e Vaporizadores/veterinária , Infecções por Orthomyxoviridae/imunologia , Infecções por Orthomyxoviridae/prevenção & controle , Infecções por Orthomyxoviridae/virologia , Projetos Piloto , Recombinação Genética , Segurança , Fatores de Tempo , Resultado do Tratamento , Vacinação/veterinária , Vacinas Atenuadas/efeitos adversos , Vacinas Atenuadas/imunologia , Proteínas não Estruturais Virais/genética , Proteínas não Estruturais Virais/imunologia , Eliminação de Partículas ViraisRESUMO
Equine herpesvirus-1 is a highly prevalent and frequently pathogenic infection of equids. The most serious clinical consequences of infection are abortion and equine herpesvirus myeloencephalopathy (EHM). In recent years, there has been an apparent increase in the incidence of EHM in North America, with serious consequences for horses and the horse industry. This consensus statement draws together current knowledge in the areas of pathogenesis, strain variation, epidemiology, diagnostic testing, vaccination, outbreak prevention and control, and treatment.
Assuntos
Infecções por Herpesviridae/veterinária , Herpesvirus Equídeo 1/fisiologia , Doenças dos Cavalos/virologia , Animais , Doenças do Sistema Nervoso Central/veterinária , Doenças do Sistema Nervoso Central/virologia , Surtos de Doenças/prevenção & controle , Surtos de Doenças/veterinária , Feminino , Infecções por Herpesviridae/epidemiologia , Infecções por Herpesviridae/prevenção & controle , Herpesvirus Equídeo 1/classificação , Doenças dos Cavalos/epidemiologia , Cavalos , Gravidez , Complicações Infecciosas na Gravidez/veterinária , Complicações Infecciosas na Gravidez/virologia , Fatores de Risco , Vacinas Virais/imunologiaRESUMO
A number of model systems have been employed to investigate age-associated changes in immune function. The purpose of the current study was to characterize senescent T cells and to investigate the inflamm-aging phenomenon both in vitro and in vivo using the old horse as a model. We examined whether decreased T cell proliferation induced by Con A is caused by increased apoptosis. We also utilized intracellular CFSE to analyze changes within each round of cell proliferation, in particular cytokine production. Intracellular staining with flow cytometry, RT-PCR, and ELISA were used to measure pro-inflammatory cytokines both in vitro and in vivo. While lymphocytes from old horses exhibit decreased proliferation, this is not the result of increased apoptosis. Instead, a larger percentage of the T cells remain in the parent generation and produce significant amounts of IFNgamma. Likewise, old horses have increased frequency of CD8-IFNgamma+ T cells and TNFalpha producing cells. We also show that old horses have elevated levels of IL-1beta, IL-15, IL-18 and TNFalpha gene expression in peripheral blood and significant levels of TNFalpha protein in serum, all characteristics of inflamm-aging.
Assuntos
Envelhecimento/imunologia , Apoptose , Proliferação de Células , Citocinas/metabolismo , Mediadores da Inflamação/metabolismo , Linfócitos T/imunologia , Fatores Etários , Animais , Apoptose/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Células Cultivadas , Senescência Celular , Concanavalina A/farmacologia , Citocinas/genética , Cavalos , Interferon gama/sangue , Interleucinas/sangue , Mitógenos/farmacologia , Modelos Animais , RNA Mensageiro/sangue , Linfócitos T/efeitos dos fármacos , Fator de Necrose Tumoral alfa/sangueRESUMO
Allergic diseases occur in most mammals, although some species such as humans, dogs and horses seem to be more prone to develop allergies than others. In horses, insect bite hypersensitivity (IBH), an allergic dermatitis caused by bites of midges, and recurrent airway obstruction (RAO), a hyperreactivity to stable born dust and allergens, are the two most prevalent allergic diseases. Allergic diseases involve the interaction of three major factors: (i) genetic constitution, (ii) exposure to allergens, and (iii) a dysregulation of the immune response determined by (i) and (ii). However, other environmental factors such as infectious diseases, contact with endotoxin and degree of infestation with endoparasites have been shown to influence the prevalence of allergic diseases in humans. How these factors may impact upon allergic disease in the horse is unknown at this time. The 3rd workshop on Allergic Diseases of the Horse, with major sponsorship from the Havemeyer Foundation, was held in Hólar, Iceland, in June 2007 and focussed on immunological and genetic aspects of IBH and RAO. This particular venue was chosen because of the prevalence of IBH in exported Icelandic horses. The incidence of IBH is significantly different between Icelandic horses born in Europe or North America and those born in Iceland and exported as adults. Although the genetic factors and allergens are the same, exported adult horses show a greater incidence of IBH. This suggests that environmental or epigenetic factors may contribute to this response. This report summarizes the present state of knowledge and summarizes important issues discussed at the workshop.
Assuntos
Obstrução das Vias Respiratórias/veterinária , Predisposição Genética para Doença/genética , Doenças dos Cavalos/imunologia , Doenças dos Cavalos/patologia , Hipersensibilidade/veterinária , Mordeduras e Picadas de Insetos/veterinária , Obstrução das Vias Respiratórias/genética , Obstrução das Vias Respiratórias/imunologia , Animais , Doenças dos Cavalos/genética , Cavalos , Hipersensibilidade/genética , Hipersensibilidade/imunologia , Hipersensibilidade/patologia , Mordeduras e Picadas de Insetos/imunologiaRESUMO
REASON FOR PERFORMING STUDY: While immune modulators are used routinely in equine medicine, their mechanism of action is not always known. OBJECTIVES: To determine the effect of a commercial preparation of inactivated parapoxvirus ovis (Orf virus; PPVO) on cytokine gene expression by equine peripheral blood mononuclear cells (PBMC) both in vitro and in vivo. METHODS: PBMC were prepared from 6 mixed-breed yearlings and cultured in vitro with PPVO with or without Concanavalin A (Con A) for 24 h. Effects on the expression of IFNalpha, IFNbeta IFNgamma, TNFalpha and IL-18 were analysed by real time quantitative PCR (RT-PCR). In addition, 12 yearling horses were treated with PPVO and whole blood RNA samples were prepared at regular intervals to assess effects on in vivo cytokine gene expression. Six of those yearlings were later treated with saline and served as treatment controls. Nine additional yearlings were injected intradermally with a single dose and their injection sites biopsied at 24 and 48 h for cytokine expression. RESULTS: In vitro culture of PBMC with PPVO led to a significant increase in IFNalpha and IFNbeta gene expression compared to mock-stimulated cultures. In addition, expression of IFNgamma and TNFalpha was significantly higher in PBMC stimulated with PPVO and Con A, than those stimulated with Con A alone. No changes were observed in IL-18 gene expression in vitro. Treatment of horses with a 3-dose regimen of PPVO resulted in elevation of IFNgamma gene expression, which was detected 24 h after the first dose and declined thereafter. Intradermal inoculation led to increased expression of IFNgamma along with IFNbeta, IL-15 and IL-18. CONCLUSIONS: Together these results indicate that PPVO stimulated IFNgamma production both in vitro and in vivo. Increased cytokine expression could account for its immunomodulatory activity. POTENTIAL RELEVANCE: The absence of adverse reactions and clear indications of increased expression of cytokine gene expression supports previous clinical uses for this immune modulator in those situations when increased expression of IFNgamma is warranted.
Assuntos
Doenças dos Cavalos/imunologia , Leucócitos Mononucleares/imunologia , Parapoxvirus/imunologia , Infecções por Poxviridae/veterinária , RNA Mensageiro/biossíntese , Regulação para Cima , Animais , Células Cultivadas , Concanavalina A/farmacologia , Doenças dos Cavalos/sangue , Cavalos , Interferon-alfa/biossíntese , Interferon-alfa/genética , Interferon beta/biossíntese , Interferon beta/genética , Interferon gama/biossíntese , Interferon gama/genética , Interleucina-18/biossíntese , Interleucina-18/genética , Ativação Linfocitária , Infecções por Poxviridae/sangue , Infecções por Poxviridae/imunologia , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/genéticaRESUMO
The increased vulnerability of foals to specific pathogens such as Rhodococcus equi is believed to reflect an innate immunodeficiency, the nature of which remains poorly understood. Previous studies have demonstrated that neonates of many species fail to mount potent Th1 responses. The current research investigates the ability of circulating and pulmonary lymphocytes of developing foals to produce interferon gamma (IFNgamma). Peripheral blood mononuclear cells (PBMC) were prepared from up to 10 horse foals at regular intervals throughout the first 6 months of life. Bronchoalveolar lavage (BAL) samples were collected at 1, 3 or 6 months of age from three groups of five foals. The PBMC and BAL cells were stimulated in vitro and IFNgamma production was measured by intracellular staining. In addition, RNA was extracted from freshly isolated and in vitro stimulated PBMC and BAL cells for quantitation of IFNgamma gene expression by real time PCR. Newborn foals exhibited a marked inability to express the IFNgamma gene and produce IFNgamma protein. This deficiency was observed in both circulating and pulmonary lymphocytes. However, IFNgamma gene expression and protein production increased steadily throughout the first 6 months of life, reaching adult levels within the first year of life. These findings suggest that foals are born with an inherent inability to mount a Th1-based cell mediated immune response which may contribute to their susceptibility to intracellular pathogens.
Assuntos
Cavalos/imunologia , Interferon gama/deficiência , Fatores Etários , Animais , Animais Recém-Nascidos , Líquido da Lavagem Broncoalveolar/citologia , Líquido da Lavagem Broncoalveolar/imunologia , Colostro/imunologia , Citometria de Fluxo/veterinária , Regulação da Expressão Gênica , Cavalos/genética , Imunidade Inata/imunologia , Interferon gama/genética , Interferon gama/imunologia , Ionomicina/farmacologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/imunologia , Ativação Linfocitária , Linfócitos/imunologia , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Distribuição Aleatória , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
Amongst the infectious diseases that threaten equine health, herpesviral infections remain a world wide cause of serious morbidity and mortality. Equine herpesvirus-1 infection is the most important pathogen, causing an array of disorders including epidemic respiratory disease abortion, neonatal foal death, myeloencephalopathy and chorioretinopathy. Despite intense scientific investigation, extensive use of vaccination, and established codes of practice for control of disease outbreaks, infection and disease remain common. While equine herpesvirus-1 infection remains a daunting challenge for immunoprophylaxis, many critical advances in equine immunology have resulted in studies of this virus, particularly related to MHC-restricted cytotoxicity in the horse. A workshop was convened in San Gimignano, Tuscany, Italy in June 2004, to bring together clinical and basic researchers in the field of equine herpesvirus-1 study to discuss the latest advances and future prospects for improving our understanding of these diseases, and equine immunity to herpesviral infection. This report highlights the new information that was the focus of this workshop, and is intended to summarize this material and identify the critical questions in the field.
Assuntos
Infecções por Herpesviridae/veterinária , Herpesvirus Equídeo 1 , Doenças dos Cavalos/virologia , Animais , Infecções por Herpesviridae/imunologia , Infecções por Herpesviridae/prevenção & controle , Infecções por Herpesviridae/virologia , Doenças dos Cavalos/imunologia , Doenças dos Cavalos/prevenção & controle , CavalosRESUMO
It has been reported that CD4(+) T lymphocytes are important in acquired immunity to gastrointestinal nematode infection. Whether these lymphocytes are also involved in the immune response of naturally resistant Gulf Coast Native (GCN) sheep to Haemonchus contortus infection remains to be defined. The objective of this study was to determine the role of CD4(+) T lymphocytes in this resistance. Ten GCN lambs were randomly assigned to a control (n=5) or a treatment (n=5) group. The treatment consisted of a series of IV injections with mouse anti-ovine CD4(+) T lymphocyte monoclonal antibodies for a period of 3 weeks. After the second treatment, all lambs were experimentally infected with 10,000 H. contortus infective larvae by oral inoculation. All lambs were monitored for fecal egg counts, blood packed cell volumes, white blood cell differential counts and serum antibody responses on a weekly basis. Fluorescence-activated cell sorter (FACS) analysis was done biweekly to enumerate CD4(+) T lymphocytes in peripheral blood. Necropsies were performed at the end of the study and 10% of the contents of the gastrointestinal tract were preserved for nematode enumeration and identification. Also at necropsy, mesenteric lymph nodes were extracted and FACS analysis was run on lymphoid cells. Mean fecal egg counts on day 21 and 28 post-infection and nematode counts at necropsy of the treated group were significantly (p<0.05) higher than that of the control group. Percent CD4(+) T lymphocytes in peripheral blood was significantly (p<0.05) lower in the treatment group than in the control group from day 9 to the end of the study. No differences were found in blood packed cell volumes, white blood cell differential counts, antibody titer or lymph node CD4(+) lymphocytes between groups. Lambs depleted of their CD4(+) T lymphocytes were more susceptible to H. contortus infection than undepleted lambs. The results of this study suggest that CD4(+) T lymphocytes are associated with the natural resistance of GCN sheep to H. contortus infection.
Assuntos
Linfócitos T CD4-Positivos/imunologia , Hemoncose/veterinária , Haemonchus/imunologia , Depleção Linfocítica/veterinária , Doenças dos Ovinos/imunologia , Abomaso/parasitologia , Animais , Anticorpos Anti-Helmínticos/administração & dosagem , Anticorpos Anti-Helmínticos/imunologia , Linfócitos T CD4-Positivos/efeitos dos fármacos , Fezes/parasitologia , Citometria de Fluxo/veterinária , Hemoncose/imunologia , Hemoncose/parasitologia , Hematócrito/veterinária , Imunidade Inata/imunologia , Contagem de Leucócitos/veterinária , Linfonodos/imunologia , Ativação Linfocitária , Camundongos , Mitógenos/farmacologia , Contagem de Ovos de Parasitas/veterinária , Distribuição Aleatória , Ovinos , Doenças dos Ovinos/parasitologiaRESUMO
Since a vaccine is not available against Rhodococcus equi, R equi-specific hyperimmune plasma (HIP) is commonly used, although its efficacy remains controversial. The objective of this study was to evaluate the ability of a commercially available HIP to prevent clinical rhodococcal pneumonia in neonatal foals after experimental challenge.
Assuntos
Animais Recém-Nascidos/imunologia , Doenças dos Cavalos/prevenção & controle , Plasma/imunologia , Pneumonia Bacteriana/veterinária , Rhodococcus equi/imunologia , Animais , Animais Recém-Nascidos/sangue , Anticorpos Antibacterianos/sangue , Ensaio de Imunoadsorção Enzimática/veterinária , Cavalos , Pneumonia Bacteriana/prevenção & controle , Índice de Gravidade de Doença , Resultado do TratamentoRESUMO
REASONS FOR PERFORMING STUDY: Rhodococcus equi (Rhodococcus hoagii/Prescottella equi) is a common cause of foal pneumonia, but its diagnosis remains a challenge for equine veterinarians. While the VapA-specific (virulence-associated protein A) immunoglobulin G (IgG) enzyme-linked immunosorbent assay (ELISA) has low sensitivity and specificity for detecting pneumonic foals, little is known about VapA-specific IgG subclasses. OBJECTIVES: To evaluate the performance of VapA-specific ELISA for IgG and its subclasses IgGa, IgGb and IgG(T) in the early diagnosis of pneumonia caused by R. equi. STUDY DESIGN: Assay validation followed by assessment of diagnostic performance using archived samples from animals of known status. METHODS: Serum samples from exposed (n = 125) and nonexposed adult horses (n = 10) and from experimentally challenged and naturally infected foals were used for ELISA validation. Post mortem and tissue culture records of the last 24 years from the Institute for Experimental Pathology at the University of Iceland in Keldur, Iceland laboratory were evaluated to confirm the absence of R. equi cases in Iceland. The diagnostic performance of VapA-specific IgG and its subclasses was evaluated using banked serum samples from pneumonic (n = 21) and healthy foals (n = 80). To evaluate each IgG assay, a cut-off value was selected based on receiver operating characteristic curve analysis and used to calculate sensitivity and specificity. The intra- and interassay coefficients of variation were calculated for each ELISA. RESULTS: Using sera from Iceland, where R. equi infection has not been reported, the VapA-specific IgG ELISA differentiated exposed from nonexposed horses. When used to identify infected foals, VapA-specific IgG, IgGa and IgGb had no diagnostic value. In contrast, IgG(T) had high sensitivity and specificity. CONCLUSIONS: Horses from Iceland are not exposed to VapA(+) R. equi and can serve as negative controls. VapA-specific IgG subclasses, with the exception of IgG(T), are poor predictors of disease. Further investigation on the use of IgG(T) as a diagnostic tool in field conditions is needed.
Assuntos
Proteínas de Bactérias/imunologia , Ensaio de Imunoadsorção Enzimática/veterinária , Doenças dos Cavalos/microbiologia , Imunoglobulina G/classificação , Pneumonia Bacteriana/veterinária , Rhodococcus equi/metabolismo , Infecções por Actinomycetales/sangue , Infecções por Actinomycetales/imunologia , Infecções por Actinomycetales/prevenção & controle , Infecções por Actinomycetales/veterinária , Animais , Animais Recém-Nascidos , Especificidade de Anticorpos , Vacinas Bacterianas/imunologia , Doenças dos Cavalos/sangue , Doenças dos Cavalos/diagnóstico , Doenças dos Cavalos/epidemiologia , Cavalos , Islândia/epidemiologia , Imunoglobulina G/sangue , Pneumonia Bacteriana/diagnóstico , Pneumonia Bacteriana/epidemiologia , Pneumonia Bacteriana/microbiologia , Estados Unidos/epidemiologiaRESUMO
Acute and chronic inflammation of the airway remains an important health problem for equids. "Heaves" or recurrent airway obstruction (RAO) remains one of the most commonly diagnosed conditions affecting the lung of older horses in Europe and the United States. The typical clinical signs of RAO include non-productive coughing, serous nasal discharge, labored expiratory effort, and flaring of the nostrils. Auscultation of the lungs of the affected horse often reveals abnormal respiratory sounds, described as crackles and wheezes, throughout the area of the lung field. These clinical signs occur secondary to an inflammatory response that results in bronchospasm, excessive mucus production and airway obstruction. This inflammatory response is characterized by the presence of excessive mucus and inflammatory cells, primarily neutrophils, in the small airways. Most evidence suggests that RAO is the result of a pulmonary hypersensitivity to inhaled antigens. Exposure of affected horses to hay dust, pollens, and mold spores leads to neutrophil accumulation in the lung and bronchospasm. The identification of allergen-specific IgE in bronchoalveolar lavage (BAL) fluid and sera of affected horses supports the involvement of a late phase, IgE-mediated, hypersensitivity reaction in the pathogenesis of equine RAO. The production of IgE antibodies is regulated by the cytokines IL-4 and IL-13. Using a quantitative PCR method we have reported that horses with RAO exhibit a modified Type 2 cytokine response characterized by the production of IL-4 and IL-13 mRNA, but not IL-5 mRNA in BAL cells. Interferon-gamma mRNA was also elevated, suggesting a mixed response. While these results are consistent with equine RAO being the result of an aberrant Type 2 cytokine response to inhaled allergens, others have failed to find any evidence of elevated Type 2 cytokine mRNA in BAL from horses with "heaves". It is likely that these disparate results could be the result of differences in the clinical stage of the affected animals or the timing of sample collection. Here, we report a diverse pattern of cytokine gene expression when sampling a group of affected horses over a period of time.
Assuntos
Obstrução das Vias Respiratórias/veterinária , Citocinas/genética , Doenças dos Cavalos/genética , Doenças dos Cavalos/imunologia , RNA Mensageiro/genética , Obstrução das Vias Respiratórias/genética , Obstrução das Vias Respiratórias/imunologia , Alérgenos , Animais , Líquido da Lavagem Broncoalveolar/imunologia , Estudos de Casos e Controles , Regulação da Expressão Gênica , Cavalos , Doença Pulmonar Obstrutiva Crônica/genética , Doença Pulmonar Obstrutiva Crônica/imunologia , Doença Pulmonar Obstrutiva Crônica/veterinária , RNA Mensageiro/biossíntese , Recidiva , Fatores de TempoRESUMO
Equine recurrent airway obstruction (RAO) is thought to result from an aberrant immune response to inhaled antigens, modulated by T lymphocytes via the secretion of pro-inflammatory cytokines. However data relating to the phenotypes of the T lymphocytes present in peripheral blood and bronchoalveolar lavage fluid of RAO horses and their cytokine profiles are contradictory. The aim of this study was to further investigate the cytokine (IL-4, IL-5, IL-13 and INF-gamma) mRNA expression profile in peripheral blood lymphocytes and bronchoalveolar lavage lymphocytes from RAO and control horses, before and at 48 h after horses were exposed to hay/straw. In contrast to previous studies, cytokine expression was quantified in populations of CD4 and CD8 T lymphocytes which were purified using magnetic bead antibody cell separation. Hay/straw exposure induced clinical airway obstruction, airway neutrophilia and airway lymphocytosis in RAO horses, and, induced a mild, but significant, airway neutrophilia in controls. However, hay/straw exposure had no significant effect on peripheral blood lymphocyte or bronchoalveolar lavage lymphocyte cytokine expression in either group. In conclusion, RAO was not associated with alterations in lymphocyte cytokine expression that are consistent with Th1 or Th2 responses, but rather with a general down-regulation in expression of the measured cytokines in peripheral blood lymphocytes and bronchoalveolar lavage lymphocytes.
Assuntos
Obstrução das Vias Respiratórias/imunologia , Obstrução das Vias Respiratórias/veterinária , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Citocinas/imunologia , Doenças dos Cavalos/imunologia , Obstrução das Vias Respiratórias/sangue , Animais , Líquido da Lavagem Broncoalveolar/imunologia , Citocinas/genética , Feminino , Cavalos , Separação Imunomagnética/veterinária , Masculino , Poaceae/imunologia , RNA/química , RNA/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa/veterinária , Estatísticas não ParamétricasRESUMO
REASONS FOR PERFORMING STUDY: Anthelmintic treatments have been associated with local inflammatory reactions. Since each class of anthelmintic has unique mechanisms of action affecting different subpopulations of parasites, we hypothesised that they will also induce characteristic proinflammatory responses. OBJECTIVES: To determine the effect of anthelmintic class on the proinflammatory response post treatment. STUDY DESIGN: Ponies naturally infected with cyathostomins and other parasites after pasture grazing were left untreated or treated with representatives of 3 different classes of anthelmintics: fenbendazole (benzimidazole); pyrantel tartrate (pyrimidine); and moxidectin (macrocyclic lactone). All were monitored for the expression of proinflammatory genes in the peripheral blood using real-time PCR. METHODS: The ponies were divided into 4 treatment groups: Group 1 (n = 4) were untreated controls; Group 2 (n = 5) received 5 daily doses of fenbendazole (10 mg/kg bwt); Group 3 (n = 4) received daily treatment of pyrantel tartrate 2× (2.65 mg/kg bwt); and Group 4 (n = 5) received a single dose of moxidectin (400 µg/kg bwt). Blood samples were collected daily for 2 weeks to determine the effect of deworming on proinflammatory gene expression. Faecal egg counts were used to evaluate the efficacy of each drug. RESULTS: While treatment with the benzimidazole significantly reduced egg counts up to 14 days post treatment, it also stimulated proinflammatory gene expression. Treatment with pyrantel salt also reduced faecal egg counts with less of a proinflammatory response. Treatment with the macrocyclic lactone was the most successful in reducing faecal egg counts and produced no signs of increased proinflammatory cytokine expression. CONCLUSIONS: This study revealed pronounced differences in the cytokine responses to anthelmintic treatment. This inflammatory reaction may play a role in the development of parasitic disease post anthelmintic treatment.
Assuntos
Anti-Helmínticos/efeitos adversos , Citocinas/metabolismo , Regulação da Expressão Gênica/efeitos dos fármacos , Doenças dos Cavalos/induzido quimicamente , Inflamação/metabolismo , Animais , Anti-Helmínticos/classificação , Anti-Helmínticos/uso terapêutico , Citocinas/genética , Fezes/parasitologia , Helmintíase Animal/tratamento farmacológico , Doenças dos Cavalos/metabolismo , Doenças dos Cavalos/parasitologia , Cavalos , Fatores de TempoRESUMO
Rhodococcus equi is a common cause of pneumonia in young foals worldwide and has considerable economic effects on the global equine industry. Despite ongoing efforts, no vaccine is currently available to prevent rhodococaal pneumonia. This is due, in part, to an incomplete understanding of the protective immune response to this bacterium. While antibodies to VapA, a lipoprotein produced by virulent R. equi, are useful in differentiating antibody production in response to pathogenic versus non-pathogenic strains, the significance of the humoral response of foals to this lipoprotein remains poorly defined. The objectives of this study were to evaluate changes in VapA-specific IgG and IgG subclasses after exposure and infection of neonatal foals. Experimental foals included those challenged with R. equi at 1 (n=18), 2 (n=4) and 3 (n=6) weeks of age. Confirmed naturally infected (n=7) and not infected (n=3) foals were also included. All foals were bled 24h after birth and weekly thereafter for a period of 8 weeks. Antibody changes over time were evaluated. Following birth, VapA-specific IgGs significantly (p<0.05) decreased over time in all foals as a result of normal decay of passively transferred antibodies. Both VapA-specific IgGa and IgG(T) significantly increased (p<0.05) after experimental challenge, however, the rise in IgG(T) occurred earlier. Only a significant (p<0.05) increase in VapA-specific IgG(T) over time was seen after natural infection. Whether VapA-specific IgG(T) can be used to differentiate rhodococcal from other pneumonias requires further investigation under field conditions.
Assuntos
Infecções por Actinomycetales/veterinária , Proteínas de Bactérias/imunologia , Doenças dos Cavalos/imunologia , Doenças dos Cavalos/microbiologia , Rhodococcus equi/imunologia , Rhodococcus equi/patogenicidade , Infecções por Actinomycetales/imunologia , Infecções por Actinomycetales/prevenção & controle , Animais , Animais Recém-Nascidos , Anticorpos Antibacterianos/sangue , Anticorpos Antibacterianos/classificação , Especificidade de Anticorpos , Proteínas de Bactérias/genética , Doenças dos Cavalos/prevenção & controle , Cavalos , Imunidade Humoral , Imunoglobulina G/sangue , Imunoglobulina G/classificação , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Rhodococcus equi/genética , Virulência/imunologiaRESUMO
REASONS FOR PERFORMING STUDY: Multiple hypotheses into the age-based susceptibility of animals to Lawsonia intracellularis exist, including the decline of passively acquired antibodies. OBJECTIVES: To determine whether the decline in passively acquired antibodies in horses is responsible for the age predilection of equine proliferative enteropathy (EPE). Additional objectives included examination of various risk factors for the development of EPE as well as the determination of naturally occurring attack rates for clinical and subclinical EPE. STUDY DESIGN: Prospective, multifarm field study. METHODS: A total of 369 mare and foal pairs from 15 central Kentucky Thoroughbred farms were used in this study, which took place from January 2012 to February 2013. Serum samples were collected from mares and foals within 48 h of parturition, and then monthly from foals to February of their yearling year. Lawsonia intracellularis-specific antibodies were measured using an enzyme-linked immunosorbent assay. RESULTS: No effect of passively acquired antibodies on the occurrence of presumptive clinical or subclinical EPE was noted. In total, 5.3% and 6.3% of seropositive horses developed presumptive clinical or subclinical EPE, respectively. In multiple logistic regression models, colts were at a significantly greater risk than fillies of developing presumptive clinical EPE (odds ratio [OR] 5.468, 95% confidence interval [CI] 1.134-26.362, P = 0.034) or a combination of either presumptive clinical or subclinical EPE (OR 3.861, 95% CI 1.461-10.206, P = 0.006) while foals that were weaned in September or beyond were at a lower risk of developing presumptive EPE (OR = 0.281, 95% CI 0.0807-0.981, P = 0.05). CONCLUSIONS: This is the first study to show that passively acquired antibodies to L. intracellularis do not have an effect on the occurrence of clinical or subclinical EPE. A number of novel findings, including identification of the disease rate among naturally exposed horses, warrant additional work as they may help to identify potential risk factors for L. intracellularis exposure and/or the reservoir host(s) of the bacterium.