Stimulatory effects of heat-killed Enterococcus faecalis on cell-mediated immunity in fish. (September 2017)

• Record Type: Journal Article
• Authors: Matsuura, Yuta; Takasaki, Miho; Miyazawa, Ryuichiro; Nakanishi, Teruyuki
• Is Part Of: Developmental and comparative immunology. Volume 74(2017)
• Page Start: 1
• Page End: 9
• Publication Date: 2017-09
• Subjects: Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2017.03.029
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: Intracellular bacterial and viral diseases are widespread in the aquaculture industry and cause serious economic losses. Development of effective vaccines and adjuvants that can induce cell-mediated immunity is urgently needed for prevention of these diseases. Here we report the immunostimulatory effects of probiotic bacteria '' E. faecalis '' in ginbuna crucian carp Carassius auratus langsdorfii . Intraperitoneal injection of heat-killed E. faecalis induced an increase in CD4-1 + lymphocytes, CD8α + lymphocytes and macrophages in vivo . Expression of Th1 cytokine genes was enhanced by exposure to the bacteria in vitro . We identified the leukocyte subsets that expressed specific Th1 cytokine genes: granulocytes and macrophages produced IL12 and IFNγrel2, respectively, while lymphocytes produced IFNγs including IFNγ1 and IFNγ2. Finally, expression of Th1 cytokines was also enhanced by intraperitoneal injection of heat-killed E. faecalis in vivo, while expression of Th2 cytokine was unchanged. Together, these findings suggest that heat-killed E. faecalis can induce cell-mediated immunity in fish. Highlights: Heat-killed Enterococcus faecalis induced an increase in CD4-1 + lymphocytes, CD8α + lymphocytes and macrophages in vivo. Heat-killed E. faecalis enhanced expression of Th1 cytokine genes including IFNγs, IFNγrels and IL12 in vitro. Stimulated granulocytes and lymphocytes by heat-killed E. faecalis in vitro expressed IL12 and IFNγs mRNA, respectively. Enhanced expression of Th1 cytokines by heat-killed E. faecalis was also observed in in vivo analysis.