Immunohistochemical and ultrastructural studies were conducted on gill of gilthead seabream, Sparus aurata L., naturally infected with the copepod ectoparasite Ergasilus lizae (Krøyer, 1863) to assess pathology and host immune cell response. Gills of 56 gilthead seabream were screened for ectoparasites and 36 specimens (64.3 %) harbored E. lizae. Intensity of infection was 32.7 ± 8.7 (mean ± S.E.). Pathological alterations to the host’s gills were more pronounced in close proximity to the copepod site of attachment. The parasite attached to the gills by means of its modified second antennae, occluded the arteries, provoked epithelial hyperplasia and hemorrhages and most often caused lamellar disruption. Near the site of E. lizae attachment numerous granular cells were encountered. In both infected and uninfected gill, the granular cells were within the filament and frequently were free within the connective tissue inside and outside the blood vessels of the filament. The type of the granular cell was identified by immunohistochemical staining with the monoclonal antibody G7 (mAb, G7), which specifically recognizes S. aurata acidophilic granulocytes (AGs), and with anti-histamine (as a marker for mast cells, MCs) on sections from 13 uninfected gills and 21 parasitized gills. The use of the mAb G7 revealed that in gills harbouring copepod, the number of G7-positive cells (i.e., AGs) (32. 9 ± 3.9, mean number of cells per 45,000 µm2 ± S.E.) was significantly higher compared to the density of the same cells in uninfected gills (15.3 ± 3.8) (ANOVA, p < 0.05). Very few histamine-positive granular cells (i.e., MCs) were found in both uninfected and parasitized gills. Here we present for the first time in S. aurata infected gill that AGs rather than MCs, are recruited and involved in the response to E. lizae.
Acidophilic granulocytes in the gills of gilthead seabream Sparus aurata: evidence of their responses to a natural infection by a copepod ectoparasite
LUI, Alice;GIARI, Luisa;SAYYAF DEZFULI, Bahram
2013
Abstract
Immunohistochemical and ultrastructural studies were conducted on gill of gilthead seabream, Sparus aurata L., naturally infected with the copepod ectoparasite Ergasilus lizae (Krøyer, 1863) to assess pathology and host immune cell response. Gills of 56 gilthead seabream were screened for ectoparasites and 36 specimens (64.3 %) harbored E. lizae. Intensity of infection was 32.7 ± 8.7 (mean ± S.E.). Pathological alterations to the host’s gills were more pronounced in close proximity to the copepod site of attachment. The parasite attached to the gills by means of its modified second antennae, occluded the arteries, provoked epithelial hyperplasia and hemorrhages and most often caused lamellar disruption. Near the site of E. lizae attachment numerous granular cells were encountered. In both infected and uninfected gill, the granular cells were within the filament and frequently were free within the connective tissue inside and outside the blood vessels of the filament. The type of the granular cell was identified by immunohistochemical staining with the monoclonal antibody G7 (mAb, G7), which specifically recognizes S. aurata acidophilic granulocytes (AGs), and with anti-histamine (as a marker for mast cells, MCs) on sections from 13 uninfected gills and 21 parasitized gills. The use of the mAb G7 revealed that in gills harbouring copepod, the number of G7-positive cells (i.e., AGs) (32. 9 ± 3.9, mean number of cells per 45,000 µm2 ± S.E.) was significantly higher compared to the density of the same cells in uninfected gills (15.3 ± 3.8) (ANOVA, p < 0.05). Very few histamine-positive granular cells (i.e., MCs) were found in both uninfected and parasitized gills. Here we present for the first time in S. aurata infected gill that AGs rather than MCs, are recruited and involved in the response to E. lizae.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
