title: Effects of tannic acid on Haemonchus contortus larvae viability and immune responses of sheep white blood cells in vitro.
abstract: Direct inhibitory effects of tannic acid on Haemonchus contortus viability were studied in vitro using the larval migration inhibition (LMI) assay. Sheep white blood cells (WBC) were preincubated with 5 and 50 lg/mL tannic acid or not followed by whole H. contortus antigen (WHA). Cells were harvested at 24 h post-incubation to test host immune responses. Concentrations of 50, 100, 500, 1000, 3000 and 5000 lg/mL tannic acid inhibited larvae migration by 19.8, 42.4, 46.3, 92.0, 93.7 and 100%, respectively, within 96 h post-incubation (P < 0.001). The relative mRNA levels of interferon (IFN)-c, interleukin (IL)-2, IL-4 and IL-10 were increased by WHA stimulation without tannic acid. However, the increased effects on IFN-c and IL-2 were inhibited by tannic acid preincubation (P < 0.001), while the increases in IL-4 and IL-10 were greatly enhanced by tannic acid preincubation (P < 0.001). Changes in protein levels of all cytokines essentially paralleled the changes in their corresponding mRNA levels. In conclusion, tannic acid is directly harmful to larvae in a dose- and time-dependent manner and modulates immune responses of sheep WBC stimulated by H. contortus antigen by inhibiting Th1 cytokines and increasing Th2 cytokine expression in vitro.
authors.forename: R Z
authors.initials: RZ
authors.lastname: Zhong
authors.forename: H X
authors.initials: HX
authors.lastname: Sun
authors.forename: H W
authors.initials: HW
authors.lastname: Liu
authors.forename: D W
authors.initials: DW
authors.lastname: Zhou
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology*; D049109:Cell Proliferation; D016207:Cytokines / Q000096:biosynthesis* / Q000276:immunology; D006189:Haemonchus / Q000187:drug effects* / Q000276:immunology* / Q000502:physiology; D016753:Interleukin-10 / Q000096:biosynthesis / Q000276:immunology; D007376:Interleukin-2 / Q000096:biosynthesis / Q000276:immunology; D015847:Interleukin-4 / Q000096:biosynthesis / Q000276:immunology; D007814:Larva / Q000276:immunology; D007962:Leukocytes / Q000276:immunology*; D008297:Male; D012756:Sheep / Q000276:immunology*; D013634:Tannins / Q000494:pharmacology*
chemical_list: D000947:Antigens, Helminth; D016207:Cytokines; D007376:Interleukin-2; D013634:Tannins; D016753:Interleukin-10; D015847:Interleukin-4