In order to assess changes in the activity of immunecompetency present in Crassostrea gigas infected with Marteilioides chungmuensis (Protozoa), the total hemocyte counts (THC), hemocyte populations, hemocyte viability, and phagocytosis rate were measured in oysters using flow cytometry. THC were increased significantly in oysters infected with M. chungmuensis relative to the healthy appearing oysters (HAO) (P<0.05). Among the total hemocyte composition, granulocyte levels were significantly increased in infected oysters as compared with HAO (P<0.05). In addition, the hyalinocyte was reduced significantly (P<0.05). The hemocyte viability did not differ between infected oysters and HAO. However, the phagocytosis rate was significantly higher in infected oysters relative to HAO (P<0.05). The measurement of alterations in the activity of immunecompetency in oysters, which was conducted via flow cytometry in this study, might be a useful biomarker of the defense system for evaluating the effects of ovarian parasites of C. gigas.
Animals ; Cell Count ; Cell Survival ; Cercozoa/*immunology/*pathogenicity ; Crassostrea/*immunology ; Flow Cytometry ; Granulocytes/immunology ; Hemocytes/immunology ; Phagocytosis

In intestinal helminth infections, Th2 immune respones are generally associated with mucin secretion for worm expulsion from the host intestine. In particular, IL-4 and IL-13 are the important cytokines related with intestinal mucus production via STAT6 signalling in nematode infections. However, this perspective has never been studied in Gymnophalloides seoi infection. The present study aimed to observe the STAT6 signalling and cytokine responses in C57BL/6 mice, a mouse strain resistant to infection with this trematode. The results showed that worm expulsion occurred actively during days 1-2 post-infection (PI), when goblet cells began to proliferate in the small intestine. The STAT6 gene expression in the mouse spleen became remarkable from day 2 PI. Moreover, G. seoi infection induced a significant increase of IL-13 from day 4 PI in the spleen of infected mice. Our results suggested that goblet cell hyperplasia and worm expulsion in G. seoi-infected mice should be induced by STAT6 signalling, in which IL-13 may be involved as a dominant triggering cytokine.
Animals ; Crassostrea ; Female ; Goblet Cells/*pathology ; Hyperplasia/pathology ; Interleukin-13/*metabolism ; Interleukin-4/*metabolism ; Intestine, Small/immunology ; Metacercariae ; Mice ; Mice, Inbred C57BL ; STAT6 Transcription Factor/*metabolism ; Signal Transduction ; Specific Pathogen-Free Organisms ; Spleen/immunology ; Trematoda/*immunology ; Trichinellosis/*immunology/parasitology