ABSTRACT
The innate immune system of honeybees mainly consists in antimicrobial peptides, cellular immunity and melanisation. In order to investigate the immune response of honeybees to immune stressors, three stress degrees were tested. Newly emerged bees naturally DWV-infected were collected from a Varroa mite-free apiary and divided into three experimental groups: naturally DWV infected bees, PBS injected bees, and artificially DWV super infected bees. Phenoloxidase activity and haemolymph cellular subtype count were investigated. Phenoloxidase activity was highest (P<0.05) in DWV-superinfected bees, and the haemocyte population differed within the three observed groups. Although, immune responses following DWV infection have still not been completely clarified, this investigation sheds light on the relation between cell immunity and the phenoloxidase activity of DWV-naturally infected honeybees exposed to additional stress such as injury and viral superinfection.(AU)
O sistema imune inato das abelhas consiste principalmente em peptídeos antimicrobianos, imunidade celular e melanização. Para investigar a resposta imune das abelhas a estressores imunológicos, foram testados três graus de estresse. Abelhas recém-emergidas naturalmente infectadas por DWV foram coletadas de um apiário livre de Varroa e divididas em três grupos experimentais: abelhas naturalmente infectadas por DWV, abelhas injetadas com PBS e abelhas superinfectadas artificialmente com DWV. A atividade de fenoloxidase e a contagem de subtipos celulares de hemolinfa foram investigadas. A atividade da fenoloxidase foi maior (P<0,05) nas abelhas super-infectadas com DWV, e a população de hemócitos diferiu entre os três grupos observados. Embora as respostas imunes após a infecção pelo DWV ainda não tenham sido completamente esclarecidas, esta investigação lança luz sobre a relação entre a imunidade celular e a atividade da fenoloxidase das abelhas infectadas naturalmente pelo DWV, expostas a estresse adicional, como lesão e superinfecção viral.(AU)
Subject(s)
Animals , Bees/virology , Hemolymph , Phosphates , Immunity, Cellular , Virus Diseases/veterinary , Monophenol MonooxygenaseABSTRACT
ABSTRACT: The innate immune system of honeybees mainly consists in antimicrobial peptides, cellular immunity and melanisation. In order to investigate the immune response of honeybees to immune stressors, three stress degrees were tested. Newly emerged bees naturally DWV-infected were collected from a Varroa mite-free apiary and divided into three experimental groups: naturally DWV infected bees, PBS injected bees, and artificially DWV super infected bees. Phenoloxidase activity and haemolymph cellular subtype count were investigated. Phenoloxidase activity was highest (P<0.05) in DWV-superinfected bees, and the haemocyte population differed within the three observed groups. Although, immune responses following DWV infection have still not been completely clarified, this investigation sheds light on the relation between cell immunity and the phenoloxidase activity of DWV-naturally infected honeybees exposed to additional stress such as injury and viral superinfection.
RESUMO: O sistema imune inato das abelhas consiste principalmente em peptídeos antimicrobianos, imunidade celular e melanização. Para investigar a resposta imune das abelhas a estressores imunológicos, foram testados três graus de estresse. Abelhas recém-emergidas naturalmente infectadas por DWV foram coletadas de um apiário livre de Varroa e divididas em três grupos experimentais: abelhas naturalmente infectadas por DWV, abelhas injetadas com PBS e abelhas superinfectadas artificialmente com DWV. A atividade de fenoloxidase e a contagem de subtipos celulares de hemolinfa foram investigadas. A atividade da fenoloxidase foi maior (P<0,05) nas abelhas super-infectadas com DWV, e a população de hemócitos diferiu entre os três grupos observados. Embora as respostas imunes após a infecção pelo DWV ainda não tenham sido completamente esclarecidas, esta investigação lança luz sobre a relação entre a imunidade celular e a atividade da fenoloxidase das abelhas infectadas naturalmente pelo DWV, expostas a estresse adicional, como lesão e superinfecção viral.
ABSTRACT
West Nile virus (WNV) is a mosquito-borne virus belonging to the family Flaviviridae included in the Japanese encephalitis antigenic complex (JEAC). A seroepidemiological study was carried out in 2011 using 160 horse sera collected from different areas of Bolivia to investigate the presence of WNV antibody. A high proportion (59.4%) of the tested sera were positive to a commercially available WNV competitive enzyme-linked immunosorbent assay (C-ELISA). Sixty-six randomly selected C-ELISA-positive sera were further tested by WNV plaque reduction neutralization test (PRNT), virus neutralization (VN), and immunoglobulin M (IgM)-WNV ELISA to exclude false-positive results due to possible cross-reactions to other members of the JEAC and to investigate if the horses were recently infected. No WNV IgM was detected in these samples, whereas neutralizing antibodies were found in 21 and 18 samples by PRNT and VN, respectively. In conclusion, a high proportion of the Bolivian horses included in this study reacted serologically against viruses of the JEAC. WNV was partially responsible (31.8%) for these reactions, supporting the conclusion that WNV circulated in Bolivia.