Modulation of immune responses of Rhynchophorus ferrugineus (Insecta: Coleoptera) induced by the entomopathogenic nematode Steinernema carpocapsae (Nematoda: Rhabditida).
Aim of this study was to investigate relationships between the red palm weevil (RPW) Rhynchophorus ferrugineus (Olivier) and the entomopathogenic nematode Steinernema carpocapsae (EPN); particularly, the work was focused on the immune response of the insect host in naive larvae and after infection with the EPN. Two main immunological processes have been addressed: the activity and modulation of host prophenoloxidase-phenoloxidase (proPO) system, involved in melanization of not-self and hemocytes recognition processes responsible for not-self encapsulation. Moreover, immune depressive and immune evasive strategies of the parasite have been investigated. Our results suggest that RPW possess an efficient immune system, however in the early phase of infection, S. carpocapsae induces a strong inhibition of the host proPO system. In addition, host cell-mediated mechanisms of encapsulation, are completely avoided by the parasite, the elusive strategies of S. carpocapsae seem to be related to the structure of its body-surface, since induced alterations of the parasite cuticle resulted in the loss of its mimetic properties. S. carpocapsae before the release of its symbiotic bacteria, depress and elude RPW immune defenses, with the aim to arrange a favorable environment for its bacteria responsible of the septicemic death of the insect target.
Department of Theoretical and Applied Sciences, University of Insubria, Varese, Italy.
Maristella
M
Mastore
Department of Sciences and Biological, Chemical and Pharmaceutical Technologies, University of Palermo, Palermo, Italy.
Vincenzo
V
Arizza
Department of Sciences and Biological, Chemical and Pharmaceutical Technologies, University of Palermo, Palermo, Italy.
Barbara
B
Manachini
Department of Theoretical and Applied Sciences, University of Insubria, Varese, Italy.
Maurizio F
MF
Brivio
D000818:Animals; D004156:Catechol Oxidase / Q000378:metabolism; D001517:Coleoptera / Q000276:immunology* / Q000469:parasitology*; D004792:Enzyme Precursors / Q000378:metabolism; D006434:Hemocytes / Q000502:physiology; D006790:Host-Parasite Interactions / Q000276:immunology*; D007111:Immunity, Cellular; D056724:Immunity, Humoral; D007814:Larva / Q000276:immunology / Q000469:parasitology; D017168:Rhabditida / Q000502:physiology*
D004792:Enzyme Precursors; C038451:pro-phenoloxidase; D004156:Catechol Oxidase
Rhynchophorus ferrugineus; Steinernema carpocapsae; encapsulation; immune depression; immune evasion; proPO system