Antimicrobial peptides (AMPs) are host defense effector molecules present in virtually all life forms. The discovery of widespread distribution of antimicrobial peptides over the last two decades had provided insights into the innate immune system that permits successful adaptation of multicellular organisms. Several types of AMPs have been identified from immune cells or from mucosal tissues of a number of teleost fish. Among these are the piscidins, which are 22-44 residues, α-helical AMPs that were originally isolated from mast cells (MCs) of hybrid striped bass. Piscidins are present in many evolutionarily advanced teleosts. Annual losses of ∼ 5-10% of the juvenile stock of European sea bass, Dicentrarchus labrax (L.) in the northern coast of the Adriatic Sea has been attributed to heavy infections of the gill monogenean Diplectanum aequans. Immunocytochemical, light and ultrastructural studies were carried out on sea bass naturally parasitized with this monogenean. Immunostaining of primary and secondary gill filaments with antibodies against the peptide antibiotics piscidin 3 (anti-HAGR) and piscidin 4 (anti-5.3-02-3A) revealed subpopulations of mast cells that were positive. In both infected and uninfected sea bass, the number of mast cells positive for piscidin 4 was higher than those immunoreactive with piscidin 3 (ANOVA, p < 0.05). The number of MCs immunoreactive to piscidin 4 in heavily infected was significantly higher than in either lightly infected (ANOVA, p < 0.05) and uninfected fish (ANOVA, p < 0.05). For piscidin 3 the number of positive MCs was significantly higher in lightly infected than in either heavily infected (ANOVA, p < 0.05) and uninfected fish (ANOVA, p < 0.05). However, for both piscidins mast cells in parasitized gills showed much stronger immunostaining intensity compared to those in unparasitized gills (ANOVA, P < 0.05). Similar studies will be conducted on gills of sea bream, Sparus aurata L., naturally infected with the important parasitic copepod Ergasilus sp. to assess pathology and cellular responses. Meanwhile, immunostaining of gill filaments showed that MCs positive for piscidin 3 were more abundant in heavily infected sea bream than in either lightly infected or uninfected fish (ANOVA, P < 0.05). Our report documents the response of gills of both fish species and provides further evidence that mast cells and their AMPs may play a role in response to branchial ectoparasite infection.

Involvement of antimicrobial peptides (piscidins 3,4) in the response to ectoparasites in aquacultured fish

SAYYAF DEZFULI, Bahram;GIARI, Luisa;LUI, Alice;
2013

Abstract

Antimicrobial peptides (AMPs) are host defense effector molecules present in virtually all life forms. The discovery of widespread distribution of antimicrobial peptides over the last two decades had provided insights into the innate immune system that permits successful adaptation of multicellular organisms. Several types of AMPs have been identified from immune cells or from mucosal tissues of a number of teleost fish. Among these are the piscidins, which are 22-44 residues, α-helical AMPs that were originally isolated from mast cells (MCs) of hybrid striped bass. Piscidins are present in many evolutionarily advanced teleosts. Annual losses of ∼ 5-10% of the juvenile stock of European sea bass, Dicentrarchus labrax (L.) in the northern coast of the Adriatic Sea has been attributed to heavy infections of the gill monogenean Diplectanum aequans. Immunocytochemical, light and ultrastructural studies were carried out on sea bass naturally parasitized with this monogenean. Immunostaining of primary and secondary gill filaments with antibodies against the peptide antibiotics piscidin 3 (anti-HAGR) and piscidin 4 (anti-5.3-02-3A) revealed subpopulations of mast cells that were positive. In both infected and uninfected sea bass, the number of mast cells positive for piscidin 4 was higher than those immunoreactive with piscidin 3 (ANOVA, p < 0.05). The number of MCs immunoreactive to piscidin 4 in heavily infected was significantly higher than in either lightly infected (ANOVA, p < 0.05) and uninfected fish (ANOVA, p < 0.05). For piscidin 3 the number of positive MCs was significantly higher in lightly infected than in either heavily infected (ANOVA, p < 0.05) and uninfected fish (ANOVA, p < 0.05). However, for both piscidins mast cells in parasitized gills showed much stronger immunostaining intensity compared to those in unparasitized gills (ANOVA, P < 0.05). Similar studies will be conducted on gills of sea bream, Sparus aurata L., naturally infected with the important parasitic copepod Ergasilus sp. to assess pathology and cellular responses. Meanwhile, immunostaining of gill filaments showed that MCs positive for piscidin 3 were more abundant in heavily infected sea bream than in either lightly infected or uninfected fish (ANOVA, P < 0.05). Our report documents the response of gills of both fish species and provides further evidence that mast cells and their AMPs may play a role in response to branchial ectoparasite infection.
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11392/1870768
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 0
social impact