RESUMO
Copper deficiency in humans and animals has been related to increased susceptibility to infections. Neutrophils are one of the most studied components of the immune response; however, to the best of our knowledge, other defenses of the innate immune system have not been analyzed in copper-deficient animals. Our previous studies in copper-deficient bovines have shown increased susceptibility to infectious keratoconjunctivitis, an ocular disease caused by Moraxella bovis. The objective of this work was to evaluate the bactericidal activity of lachrymal secretion and complement system, two main mechanisms of the innate immune response against M. bovis, in copper-deficient cattle. Our results indicate that copper deficiency has no effect on bactericidal activity of complement system and lachrymal secretion against M. bovis in calves. Other components of local and systemic ocular defense mechanisms that could explain the increased susceptibility to infectious keratoconjunctivitis observed in copper-deficient bovines should be investigated.
Assuntos
Antibacterianos/farmacologia , Proteínas do Sistema Complemento , Cobre/deficiência , Aparelho Lacrimal/metabolismo , Animais , Bovinos , Ceratoconjuntivite Infecciosa/imunologiaRESUMO
In this work two cytokines were used in combination with inactivated bacteria (bacterin) to test the bovine conjuctival immune response to the pathogen Moraxella bovis, the causative agent of Infectious bovine keratoconjunctivitis (IBK). Treatments using the bacterin vaccine combined with interleukin-2 and interferon-α as adjuvants (Group A), the bacterin vaccine only (Group B), and controls without treatment (Group C), were applied by ocular spraying to evaluate the local immune response in the corneal structure of cattle experimentally infected with M. bovis. Six weeks after infection, 14 out of a total of 34 animals presented different corneal lesions; 9 corresponding to the control group C, 4 to the group B and only one to the group A. According to the clinical manifestations, a numeric score was calculated. Control animals presented the highest score value (12 points), followed by group B (7.5 points) and group A (1 point). These results suggest that the addition of cytokines to M. bovis treatments can reduce not only eye injuries caused by IBK but also the number of diseased animals.
Assuntos
Adjuvantes Imunológicos/uso terapêutico , Vacinas Bacterianas/uso terapêutico , Doenças dos Bovinos/prevenção & controle , Citocinas/uso terapêutico , Ceratoconjuntivite Infecciosa/prevenção & controle , Moraxella bovis , Infecções por Moraxellaceae/veterinária , Animais , Bovinos , Doenças dos Bovinos/imunologia , Doenças dos Bovinos/microbiologia , Interferon-alfa/uso terapêutico , Interleucina-2/uso terapêutico , Ceratoconjuntivite Infecciosa/imunologia , Ceratoconjuntivite Infecciosa/microbiologia , Moraxella bovis/imunologia , Infecções por Moraxellaceae/imunologia , Infecções por Moraxellaceae/prevenção & controleRESUMO
Infectious bovine keratoconjunctivitis (IBK) is an acute disease caused by Moraxella bovis (Mb). Several factors may predispose animals to an IBK outbreak; one commonly observed is infection with bovine herpes virus type 1 (BHV-1). The aim of this study was to investigate the dynamics of BHV-1 virus infection and its relation with clinical cases of IBK in weaned calves from a beef herd with a high prevalence of lesions caused by Mb. Sampling was carried out in six stages and included conjunctival swabs for isolating Mb as well as blood samples for identifying antibodies specific for BHV-1. A score for IBK lesions after observing each eye was determined. The findings of this study showed a high prevalence of BHV-1 virus infection (100% of animals were infected at the end of the trial); 67% of animals were culture-positive for Mb, but low rates of clinical IBK (19% of calves affected) were detected at the end of the trial. These results suggest that infection with BHV-1 did not predispose these animals to IBK, and that Mb infection produced clinical and subclinical disease in the absence of BHV-1 co-infection.
Assuntos
Surtos de Doenças/veterinária , Herpesvirus Bovino 1/imunologia , Ceratoconjuntivite Infecciosa/microbiologia , Moraxella bovis , Infecções por Moraxellaceae/veterinária , Animais , Anticorpos Antivirais/sangue , Bovinos , Imunidade Humoral , Ceratoconjuntivite Infecciosa/complicações , Ceratoconjuntivite Infecciosa/imunologia , Ceratoconjuntivite Infecciosa/patologia , Infecções por Moraxellaceae/imunologia , Infecções por Moraxellaceae/virologiaRESUMO
Infectious bovine keratoconjunctivitis (IBK), caused by Moraxella bovis, is a disease of major importance in cattle industry. M. bovis has several virulence factors among which pili are crucial antigen for the protective capacity of vaccines against this disease. The production of vaccines against IBK therefore requires a reliable technique for cellular piliation level assessment on cells to be included as vaccine components. In this study we describe a specific whole-bacterial cell enzyme-linked immunosorbent assay (bact-ELISA) capable of detecting pili antigen on M. bovis cell surface. A sequential competitive bact-ELISA was developed using highly piliated M. bovis cells as antigen. Samples to be analyzed were allowed to react with anti-pilus serum prior to incubation in wells coated with piliated cells of M. bovis. This assay proved useful for the rapid, sensitive and reproducible evaluation of piliation on M. bovis cells, and represents an important tool for cellular piliation monitoring daburing M. bovis cells production in stirred bioreactors.