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Trình bày được nguyên lý của các kỹ thuật miễn dịch học chẩn đoán giun sán. Thực hiện được xét nghiệm ELISA chẩn đoán một số bệnh ký sinh trùng thường gặp. Kỹ thuật ngưng kết hồng cầu gián tiếp ELISA gián tiếp Kỹ thuật ngưng kết hạt Latex Sandwich ELISA Dipsticks assayChromatography Immunoblot assay Kỹ thuật khác
Xét nghiệm miễn dịch học chẩn đoán Giun – Sán ký sinh Mục tiêu • Trình bày ngun lý kỹ thuật miễn dịch học chẩn đoán giun sán • Thực xét nghiệm ELISA chẩn đốn số bệnh ký sinh trùng thường gặp Nội dung Giới thiệu Kỹ thuật ngưng kết hồng cầu gián tiếp ELISA gián tiếp Kỹ thuật ngưng kết hạt Latex Sandwich ELISA Dipsticks assay/Chromatography Immunoblot assay Kỹ thuật khác Kết luận Giới thiệu IgG IgE hợp tác loại bỏ S venezuelensis (A) To examine which classes of Igs are able to induce worm expulsion We injected IgG Fr (1.8 mg), IgE Fr (5 μg), or a mixture of IgG Fr (1.8 mg) and IgE Fr (5 μg) into AID−/− mice on day after infection with 4,000 L3, and adult worms were recovered at day As shown here, IgG and IgE reduced worm burdens collaboratively. (B) Hypothetical mechanism of IgG- and IgE-mediated worm expulsion • IL-12 and parasite infection Early in infection with intracellular parasites, IL-12 is produced by phagocytic cells and induces the production of IFN-γ by natural killer (NK) cells and T cells This early production of IFN-γ may help control infection by immediately activating macrophages In addition, IL-12 and the IL-12-driven cytokine IFN-γ favour the development of parasite-specific TH1 cells, in addition to inducing the production of high levels of IFNγ by already differentiated TH1 cells • This early production of Il-12 is functionally analogous to the early induction of IL-4 synthesis by helminthic parasites, which drives TH2 development Any helminthic parasite that does not induce the production of IL-12 may contribute to the development of TH2 as a default pathway Mechanisms of immune modulation by helminth ES products (in bold) and defined molecules (in plain type) discussed in the text Abbreviations: APC, antigen presenting cell; ASP, Ancylostoma secreted protein; BES, B malayi ES; CPI, cysteine proteinase inhibitor (cystatin); HES, H polygyrus ES; IPSE, IL-4-inducing principle of schistosome eggs; L-NES, larval N brasiliensis ES; MIF, macrophage migration inhibitory factor; NES, adult N brasiliensis ES; NIF, neutrophil inhibitory factor; Sm, Schistosoma mansoni; SPN, serine proteinase inhibitor (serpin); TLR, toll-like receptor; TGF, transforming growth factor; TES, T canis ES Protective TH2-type response during intestinal nematode infection • Infective third-stage larvae (L3) are ingested by the host They then travel to the duodenum, invade the epithelia, and reside in the submucosa for days, after which they reenter the lumen of the duodenum as adult nematodes Primary infections become established and chronic, but can be cleared by antihelminthic drug treatment Challenge (secondary) infections are naturally cleared by the host by day 14 post-infection, making this an excellent model of protective memory T helper (TH2)-type responses Parasite antigens are presented to CD4+ T cells in mesenteric lymph nodes and other gut-associated lymphoid tissues, driving the induction of TH2 effector cells These cells exert their effector functions through the production of a number of cytokines, including interleukin-4 (IL-4), IL-13, IL-9 and IL-5 TH2 cells induce B-cell immunoglobulin classswitching to IgE Shortly after activation, TH2 effector cells migrate to the site of parasite residence in the submucosa Within several days, a distinct immune-cell infiltrate appears which can damage the larval parasite after secondary, but not primary, inoculation The infiltrate following secondary inoculation includes TH2 cells, dendritic cells (DCs), neutrophils and alternatively activated macrophages (AAMs) The TH2 cytokines IL-4 and IL-13 might also facilitate expulsion of adult parasites in the lumen by inducing changes in intestinal physiology TH2-cell functions during helminth infection • T helper (TH2) cells orchestrate the immune response primarily through the production of cytokines in the lymph nodes and periphery Interleukin-5 (IL-5) triggers eosinophilia, and in conjunction with IL-4, IL-9, and IL-13, and the crosslinking of FcεRIs (high-affinity Fc receptors for IgE), can result in enhanced mast-cell and basophil development and release of mediators IL-4 and IL-13 stimulate increased smooth-muscle-cell contractility, increased intestinal permeability and elevated goblet-cell mucous secretion IL-4 and IL-13 also enhance responsiveness of these cell types to mast-cell-derived mediators Collectively, these effects can contribute to the ‘weep and sweep’ response to intestinal helminths IL-4, in conjunction with other signals, can induce class switching in B cells, leading to IgE production IL-4, IL-13 and IL-21, can drive development of alternatively activated macrophages (AAMs), leading to upregulation of arginase-1 expression, and in some cases this might lead to fibrosis, as in chronic schistosomiasis IL-25 expression stimulates a c-KIT+FcεRI− population to migrate to lymph nodes and upregulate TH2-type cytokine mRNAs It is unclear whether IL-25 is a TH2-type cytokine, or whether it is expressed by a distinct TH-cell lineage IL-21, also produced by TH17 cells, is instrumental in the development of a TH17-like response (not shown) ChaFFs, chitinase and FIZZ family members; RELM, resistin-like molecule