Coordinated Muc2 and Muc3 mucin gene expression in Trichinella spiralis infection in wild-type and cytokine-deficient mice

Mucin hypersecretion is an important component of the immune response to gastrointestinal nematode infection. Two discrete types of mucin proteins exist in the mouse intestine, secretory Muc2 and membrane-bound Muc3. We examined Muc2 and Muc3 expression in wild-type mice and mice lacking gamma interferon receptor (IFNR–/–), tumor necrosis factor receptor 1 (TNFR1–/–) and interleukin 4 (IL4–/–) infected with Trichinella spiralis. Infected wild-type mice demonstrated significant goblet cell hyperplasia and increased mucin glycoprotein. In situ hybridization showed this was accompanied by increases in Muc2 and Muc3 mRNA. Total intestinal mucin protein and Muc2 and Muc3 mRNA levels were also significantly increased in cytokine-deficient mice. These data demonstrate the coordinated up-regulation of two types of mucin genes in response to T. spiralis infection and may form the basis of an innate mucosal response independent of IFN-, TNF, and IL-4.     

Interleukin-4 influences the production of microfilariae in a mouse model of Brugia infection

Sub-cutaneous infection of interleukin (IL)-4-/- mice on the BALB/c background with third stage larva (L3) of Brugia pahangi revealed an altered cytokine profile consistent with the absence of the Th2 promoting cytokine IL-4. Splenocytes from IL-4-/- mice secreted significantly more antigen (Ag)-specific IL-2 and interferon-gamma and significantly less Ag-specific IL-5, compared to those from L3-infected wild-type mice. However, levels of Ag-specific IL-13 were similar between groups. Despite the alteration in immune responses, there was no significant difference in recovery of developing worms from the peritoneal cavity of the two strains of mice at any time postinfection. However, at later time points of infection, the IL-4-/- mice contained large numbers of microfilariae (Mf) in the peritoneal cavity while the wild-type mice contained comparatively few Mf. The differences in Mf levels appear to relate to differences in worm fecundity in the two strains of mice, with adult female worms from the wild-type mice containing few developing Mf. Moreover, implantation of sexually mature adult female worms into the peritoneal cavity of both strains of mice resulted in equal levels of Mf, confirming that the primary role of IL-4 is to limit fecundity during the maturation phase of infection.     

RELMbeta/FIZZ2 is a goblet cell-specific immune-effector molecule in the gastrointestinal tract

Gastrointestinal (GI) nematode infections are an important public health and economic concern. Experimental studies have shown that resistance to infection requires CD4(+) T helper type 2 (Th2) cytokine responses characterized by the production of IL-4 and IL-13. However, despite >30 years of research, it is unclear how the immune system mediates the expulsion of worms from the GI tract. Here, we demonstrate that a recently described intestinal goblet cell-specific protein, RELMbeta/FIZZ2, is induced after exposure to three phylogenetically distinct GI nematode pathogens. Maximal expression of RELMbeta was coincident with the production of Th2 cytokines and host protective immunity, whereas production of the Th1 cytokine, IFN-gamma, inhibited RELMbeta expression and led to chronic infection. Furthermore, whereas induction of RELMbeta was equivalent in nematode-infected wild-type and IL-4-deficient mice, IL-4 receptor-deficient mice showed minimal RELMbeta induction and developed persistent infections, demonstrating a direct role for IL-13 in optimal expression of RELMbeta. Finally, we show that RELMbeta binds to components of the nematode chemosensory apparatus and inhibits chemotaxic function of a parasitic nematode in vitro. Together, these results suggest that intestinal goblet cell-derived RELMbeta may be a novel Th2 cytokine-induced immune-effector molecule in resistance to GI nematode infection.     

Immunoglobulin E and mast cell responses are related to worm biomass but not expulsion of Hymenolepis diminuta during low dose infection in rats

It is well known that the destrobilation and later expulsion are characteristics of multiple Hymenolepis diminuta infections in rats. This process is suggested to be mediated by a variety of host cellular responses. It has also been suggested that immunoglobulin (Ig) E may have a beneficial role for some cestodes including H. diminuta. We examined the intestinal mast cell and serum IgE responses to a 10-H. diminuta infection in three different rat strains. Tapeworm infection induced no increased mast cell and IgE responses in F344 rats in which neither worm biomass nor worm burden decreased during 6 weeks of observation. The number of mast cells and amounts of serum rat mast cell protease (RMCP) II and IgE markedly increased from 3 weeks postinfection (p.i.) in BN rats. The worm biomass in BN rats was significantly lower than that in F344 rats, but worm burden was not different from that in F344 rats at 3 or 6 weeks p.i. In DA rats, the number of mast cells and levels of serum RMCP II and IgE increased at 6 weeks but not at 3 weeks p.i. Although numbers of mast cells and serum RMCP II and IgE levels were lower in DA rats than in BN rats, smaller and fewer worms were recovered in DA rats than in F344 and BN rats at from 3 and 6 weeks p.i. Worms were recovered from all of F344 and BN rats, while only 40% of DA rats harboured worms at 6 weeks p.i. These results suggested that the worm biomass was related to mast cell and IgE responses, but these responses were not required for worm expulsion during low dose H. diminuta infection in rats.     

Persistent infection of Strongyloides venezuelensis and normal expulsion of Nippostrongylus brasiliensis in Mongolian gerbils, Meriones unguiculatus, with reference to the cellular responses in the intestinal mucosa

The kinetics of daily faecal egg count, worm burdens, and intestinal cellular responses were examined in Mongolian gerbils after infection with either Strongyloides venezuelensis or Nippostrongylus brasiliensis alone, or concurrently with both parasites. The results show that, both in individual and concurrent infections, S. venezuelensis infection persisted for over 10 weeks and elicited a gradual increase in number of mast cells in the jejunal mucosa. On the other hand, N. brasiliensis worms were expelled by 3 weeks in association with goblet cell hyperplasia. These results suggest that effector/regulator cells involved in worm expulsion are different and highly selective depending on the genus of intestinal helminths.     

Worm expulsion is independent of alterations in composition of the colonic bacteria that occur during experimental Hymenolepis diminuta-infection in mice

ABSTRACT

The tapeworm Hymenolepis diminuta fails to establish in mice. Given the potential for helminth-bacteria interaction in the gut and the influence that commensal bacteria exert on host immunity, we tested if worm expulsion was related to alterations in the gut microbiota. Specific pathogen-free (SPF) mice, treated with broad-spectrum antibiotics, or germ-free wild-type mice were infected with H. diminuta, gut bacterial composition assessed by 16S rRNA gene sequencing, and worm counts, blood eosinophilia, goblet cells, splenic IL-4, -5 and -10, and colonic cytokines/chemokines mRNA were assessed. Effects of a PBS-soluble extract of adult H. diminuta on bacterial growth in vitro was tested. H. diminuta-infected mice displayed increased α and β diversity in colonic mucosa-associated and fecal bacterial communities, characterized by increased Lachnospiraceae and clostridium cluster XIVa. In vitro analysis revealed that the worm extract promoted the growth of anaerobic bacteria on M2GSC agar. H. diminuta-infection was accompanied by increased Th2 immune responses, and colon from infected mice had increased levels of IL-10, IL-25, Muc2, trefoil factor 3, and β2-defensin mRNA. SPF-mice treated with antibiotics, or germ-free mice, expelled H. diminuta with kinetics similar to control SPF mice. In both settings, measurements of Th2-immune responses were not significantly different across the groups. Thus, while infection with H. diminuta results in subtle but distinct changes to the colonic microbiota, we have no evidence to support an essential role for gut bacteria in the expulsion of the worm from the mouse host.     

Isolates of Trichuris muris elicit different adaptive immune responses in their murine host

The J and S isolates of Trichuris muris have different infection profiles in C57BL/6 mice; J worms are expelled, S worms survive to chronicity. Building on this, the ability of the J and S isolates to survive, and the quality of the immune response induced was explored in three different strains of mouse. The resistant BALB/c mouse mounted a strong Th2 response against both isolates, which were quickly expelled. The susceptible AKR host mounted a Th1 response and retained both isolates. Despite equivalent worm exposure, mesenteric lymph node cells from AKR mice infected with the S isolate produced significantly higher levels of IL-12 and the intestinal mastocytosis was reduced. IgG1 and IgG2a from S-infected AKR mice recognized low molecular weight antigens not recognized by J-infected mice. Differential expulsion kinetics was observed in the slower-responding C57BL/6 strain; J worms were expelled but S isolate worms were retained. Survival of the S isolate was again associated with elevated IL-12 and decreased Th2 responses. In resistant mouse strains, the outcome of infection is thus dominantly influenced by host genetics. However, in the slower-responding host, isolate-derived factors may play a role in shaping the quality of the adaptive immune response, thus influencing parasite survival.     

Histochemical characteristics of the goblet cell mucins and their role in defence mechanisms against Nippostrongylus brasiliensis infection in the small intestine of mice

The histochemical characteristics of the small intestinal goblet cell mucins of mice and their protective role during the expulsion of Nippostrongylus brasiliensis adult worms were examined. Lectin histochemistry revealed that, before infection, strongly positive stainability of Helix pomatia agglutinin (HPA) and Limax flavus agglutinin (LFA) was observed in all of the small intestinal goblet cell mucins of mice. When ‘normal’or ‘damaged’N. brasiliensis adult worms were implanted separately into the small intestine of euthymic mice, 50% of them were established in the intestine on day one after implantation, but were subsequently expelled within one week in association with HPA and LFA positive goblet cell hyperplasia. On the other hand, in dexamethasone treated euthymic mice, 70% of implanted ‘normal’worms were expelled by day 7 and 80% of implanted ‘damaged’worms were expelled by day 4 in association with HPA and LFA positive goblet cell mucins but no goblet cell hyperplasia. This is consistent with the fact that, in spite of no increase in goblet cell number in hypothymic nu/nu mice, all of the implanted ‘damaged’worms were expelled within day 5 and 80% of implanted ‘normal’worms were expelled by day 14 post implantation, possibly associated with strngly expressed terminal GalNAc and sialic acid residues of the small intestinal goblet cell mucins prior to infection.     

Sphingosine kinase 1 regulates mucin production via ERK phosphorylation

Our previous report showed that inhibition of sphingosine kinase (SphK) ameliorates eosinophilic inflammation and mucin production in a mouse asthmatic model. To clarify the role of SphK in airway mucin production, we utilized the mouse asthmatic model and found that both SphK and MUC5AC expression were increased and co-localized in airway epithelium. Next we cultured normal human bronchial epithelial cells in an air–liquid interface and treated with IL-13 to induce their differentiation into goblet cells. We found that SphK1 and MUC5AC expression was increased by IL-13 treatment at both protein and mRNA levels, whereas SphK2 expression was not changed. N,N-dimethylsphingosine (DMS), a potent SphK inhibitor, decreased MUC5AC expression up-regulated by IL-13 treatment. Furthermore, DMS inhibited IL-13-induced ERK1/2 phosphorylation but neither p38 MAPK nor STAT6 phosphorylation. These results suggest that SphK1 is involved in MUC5AC production induced by IL-13 upstream of ERK1/2 phosphorylation, and independent of STAT6 phosphorylation.     

Circulating cytokine levels and antibody responses to human Schistosoma haematobium: IL-5 and IL-10 levels depend upon age and infection status

Experimental schistosome infections induce strong parasite-specific Th2 responses. This study aims to relate human systemic cytokine and antibody levels to schistosome infection levels and history. Levels of anti-Schistosoma haematobium antibodies (directed against crude cercariae, egg and adult worm antigens) and plasma cytokines (IFN-γ, IL-2, IL-4, IL-5, IL-10, IL-13, IL-17, IL-21, and IL-23) were measured by ELISA in 227 Zimbabweans (6-60?years old) in a schistosome-endemic area and related to age and infection status. Egg-positive people had significantly higher levels of specific antibodies, IL-2, IFN-γ and IL-23. In contrast, egg-negative individuals had significantly higher circulating IL-10, IL-4, IL-13 and IL-21 that were detected with high frequency in all participants. Subjects with detectable plasma IL-17 produced few or no eggs. When analyzed by age, IL-4 and IL-10 increased significantly, as did schistosome-specific antibodies. However, when age was combined with infection status, IL-5 declined over time in egg-positive people, while increased with age in the egg-negative group. Older, lifelong residents had significantly higher IL-4 and IL-5 levels than younger egg-negative people. Thus, a mixed Th1/Th2 systemic environment occurs in people with patent schistosome infection, while a stronger Th2-dominated suite of cytokines is evident in egg-negative individuals.     

Overexpressing mouse model demonstrates the protective role of Muc5ac in the lungs

MUC5AC, a major gel-forming mucin expressed in the lungs, is secreted at increased rates in response to infectious agents, implying that mucins exert a protective role against inhaled pathogens. However, epidemiological and pathological studies suggest that excessive mucin secretion causes airways obstruction and inflammation. To determine whether increased MUC5AC secretion alone produces airway obstruction and/or inflammation, we generated a mouse model overexpressing Muc5ac mRNA ∼20-fold in the lungs, using the rCCSP promoter. The Muc5ac cDNA was cloned from mouse lungs and tagged internally with GFP. Bronchoalveolar lavage fluid (BALF) analysis demonstrated an approximate 18-fold increase in Muc5ac protein, which formed high-molecular-weight polymers. Histopathological studies and cell counts revealed no airway mucus obstruction or inflammation in the lungs of Muc5ac-transgenic (Muc5ac-Tg) mice. Mucus clearance was preserved, implying that the excess Muc5ac secretion produced an “expanded” rather than more concentrated mucus layer, a prediction confirmed by electron microscopy. To test whether the larger mucus barrier conferred increased protection against pathogens, Muc5ac-Tg animals were challenged with PR8/H1N1 influenza viruses and showed significant decreases in infection and neutrophilic responses. Plaque assay experiments demonstrated that Muc5ac-Tg BALF and purified Muc5ac reduced infection, likely via binding to α2,3-linked sialic acids, consistent with influenza protection in vivo. In conclusion, the normal mucus transport and absence of a pulmonary phenotype in Muc5ac-Tg mice suggests that mucin hypersecretion alone is not sufficient to trigger luminal mucus plugging or airways inflammation/goblet cell hyperplasia. In contrast, increased Muc5ac secretion appears to exhibit a protective role against influenza infection.     

Up-regulation of gasdermin C in mouse small intestine is associated with lytic cell death in enterocytes in worm-induced type 2 immunity

“Taste-like” tuft cells in the intestine trigger type 2 immunity in response to worm infection. The secretion of interleukin-13 (IL-13) from type 2 innate lymphoid cells (ILC2) represents a key step in the tuft cell–ILC2 cell–intestinal epithelial cell circuit that drives the clearance of worms from the gut via type 2 immune responses. Hallmark features of type 2 responses include tissue remodeling, such as tuft and goblet cell expansion, and villus atrophy, yet it remains unclear if additional molecular changes in the gut epithelium facilitate the clearance of worms from the gut. Using gut organoids, we demonstrated that IL-4 and IL-13, two type 2 cytokines with similar functions, not only induced the classical type 2 responses (e.g., tuft cell expansion) but also drastically up-regulated the expression of gasdermin C genes (Gsdmcs). Using an in vivo worm-induced type 2 immunity model, we confirmed the up-regulation of Gsdmcs in Nippostrongylus brasiliensis–infected wild-type C57BL/6 mice. Consistent with gasdermin family members being principal effectors of pyroptosis, overexpression of Gsdmc2 in human embryonic kidney 293 (HEK293) cells triggered pyroptosis and lytic cell death. Moreover, in intestinal organoids treated with IL-4 or IL-13, or in wild-type mice infected with N. brasiliensis, lytic cell death increased, which may account for villus atrophy observed in worm-infected mice. Thus, we propose that the up-regulated Gsdmc family may be major effectors for type 2 responses in the gut and that Gsdmc-mediated pyroptosis may provide a conduit for the release of antiparasitic factors from enterocytes to facilitate the clearance of worms.

Helminth (worm) infection remains prevalent in developing countries and represents a significant health burden that negatively affects the development and health of infected children (1). Type 2 immunity is the primary host defense mechanism for helminth infection, mediating physiological changes that facilitate worm expulsion (2).The interaction of tuft cells with type 2 innate lymphoid cells (ILC2) and the subsequent interaction of ILC2 cells with intestinal epithelial cells represent a primary circuit that initiates and sustains type 2 responses in the intestines (3–5). Tuft cells detect parasites, protozoans, and other infectious microbes via tuft cell–expressed Sucnr1 or other poorly characterized receptors to initiate type 2 responses (6–8). The activation of taste signaling elements expressed in tuft cells, such as gustducin and Trpm5, leads to the secretion of interleukin-25 (IL-25), leukotrienes, and other mediators (3–9). Subsequently, IL-25 activates mucosal ILC2 cells to secrete IL-13 (10–14), which contributes to gut tissue remodeling, including tuft and goblet cell expansion, and villus atrophy (3–5, 10, 15, 16). Despite the fact that worm-induced cellular remodeling of the gut epithelium is well established, how the gut gets rid of worms remains unclear, especially at the molecular level. We hypothesized that molecular changes in gut epithelium may occur upon worm infection, which may prepare intestinal epithelial cells to contribute to an inflammatory environment and facilitate the expulsion of worms from the gut. Because the type 2 cytokines IL-13 and IL-4 act as master cytokines that regulate type 2 immunity (15), the identification of target genes for these type 2 cytokines may fill the gap in our understanding of the molecular changes responsive to type 2 cytokines or infectious parasites.Gasdermin proteins are key effectors of pyroptosis, a highly inflammatory form of programmed cell death triggered by intracellular and extracellular pathogens, which represents a prominent antimicrobial response (17–19). Rodents have four gasdermin C proteins (Gsdmcs) compared to a single GSDMC protein in humans. The functions of Gsdmcs within the family of gasdermin proteins are poorly explored. However, a recent publication showed that human GSDMC can facilitate the production of tumor necrosis by inducing pyroptosis (20). Here, we demonstrated that the up-regulation of Gsdmc genes is a key feature of mucosal type 2 immunity. Like other gasdermin family members, Gsdmc2 is a pyroptotic effector, and overexpression of Gsdmc2 can lead to pyroptosis in cell culture systems. Up-regulation of Gsdmcs and the cleavage of Gsdmcs correlate with lytic cell death in intestinal epithelial cells in mice infected with the parasitic worm Nippostrongylus brasiliensis, a strong inducer of type 2 immunity, and in cultured intestinal organoids treated with type 2 cytokines. Lytic cell death may be a part of the host defense mechanism to facilitate worm clearance through the release of antiparasitic factors into the gut lumen.     

Interleukin-5 deficient mice exhibit impaired host defence against challenge Trichinella spiralis infections

Enteric nematode infections are characterized by both peripheral and tissue eosinophilia. The cytokine interleukin (IL)-5 is considered a critical factor in the proliferation and recruitment of eosinophils, however, studies suggest it plays little role in host defence, at least during primary Trichinella spiralis infections. Less is known concerning its role in host defence or in the inflammatory response that develops against challenge infections with the same parasite. We examined these questions by infecting IL-5 deficient and wild-type mice, with T. spiralis parasites. Both strains expelled the primary infection by day 21. Forty days after the primary infection, we challenged the mice with a second T. spiralis infection and counted tissue eosinophils and worms in the intestine. While wild-type mice developed a large tissue eosinophilia, IL-5 deficient mice showed little increase in eosinophil numbers within the intestine. Throughout the challenge infection, significantly larger worm burdens were recovered from IL-5 deficient mice, and worm expulsion was also significantly slower (day 21) compared to wild-type mice (day 14). Thus, unlike in a primary infection, IL-5 is not only essential for the onset of intestinal eosinophilia, but also makes a significant contribution to enteric host defence during challenge T. spiralis infections.     

The Regulation of the IL-18 on Group 2 Innate Lymphoid Cells in Allergic Rhinitis

Background: Group 2 innate lymphoid cells (ILC2s) promote allergic inflammation by producing interleukin-4 (IL-4), IL-5, IL-9, and IL-13. IL-18 can promote T helper 2 cell (Th2) response by inducing IL-4, and IL-13 production from mast cells and basophils. However, the regulation of IL-18 on ILC2s remained unknown. Objective: To investigate the regulatory role of IL-18 in inducing the type 2 innate lymphoid cells. Methods: Twenty patients with allergic rhinitis (AR) and 20 controls were enrolled. The mRNA and protein levels of IL-18 in serum, as well as the frequencies of ILC2 in peripheral blood mononuclear cells (PBMCs) were measured by real-time polymerase chain reaction (PCR), enzyme-linked immunosorbent assay (ELISA), and flow cytometry. The ILC2s were sorted and the mRNA expression of IL-18 receptor in ILC2 was analyzed by real-time PCR. The effects of IL-18 on the proliferation and type 2 cytokine production were detected by tritiated thymidine incorporation test, real-time PCR, and ELISA, respectively. Results: The levels of IL-18 mRNA and protein were significantly higher in AR patients than in the controls (P<0.05). The frequency of ILC2 in peripheral blood was elevated in the AR patients than in the controls. After stimulation by IL-18 and house dust mite (HDM), the expression of IL-18 receptor (IL-18R) by ILC2 was significantly up-regulated. The tritiated thymidine incorporation results showed that IL-18 promoted the proliferation of ILC2 in a dose-dependent manner. IL-18 also induced the expression of IL-5 and IL-13 proteins by ILC2. Conclusion: Our results confirmed -for the first time- the effect of IL-18 in innate immunity, which was demonstrated by direct effect on the differentiation and function of ILC2.     

SerpinB2 deficiency modulates Th1⁄Th2 responses after schistosome infection

SerpinB2, also known as plasminogen activator inhibitor type-2, is a major product of macrophages and is upregulated during many infections. Although SerpinB2 inhibits urokinase plasminogen activator in vitro, evidence that this represents its physiological role in vivo is not compelling. We have recently shown that SerpinB2-/-mice generate enhanced Th1 responses after immunization with a Th1 immunogen. Herein,we show that Schistosoma japonicum granulomas induced liver SerpinB2 mRNA expression by >600-fold in wild-type mice. In SerpinB2-/- mice, worm and egg burden, and granuloma number and volume were unaffected. However, granulomas in these mice were associated with reduced fibrosis (as determined by Sirius red staining and image analysis) and increased iNOS, IL-6, IL-10 and TNFa and decreased Arg 1 and IL-13 mRNA expression. SerpinB2-/- mice immunized with soluble egg antigen (SEA) also showed reduced levels of SEA-specific IgG1. SerpinB2 deficiency thus promoted certain Th1 and reduced certain Th2 responses in response to this Th2 immunogen.     

IL-1 family members and STAT activators induce cytokine production by Th2, Th17, and Th1 cells

Expression of T1ST2, the IL-33R, by Th2 cells requires GATA3. Resting Th2 cells express little GATA3, which is increased by IL-33 and a STAT5 activator, in turn increasing T1ST2 from its low-level expression on resting Th2 cells. Th2 cells that have upregulated T1ST2 produce IL-13, but not IL-4, in response to IL-33 plus a STAT5 activator in an antigen-independent, NF-κB-dependent, cyclosporin A (CsA)-resistant manner. Similarly, Th17 cells produce IL-17A in response to IL-1β and a STAT3 activator and Th1 cells produce IFNγ in response to IL-18 and a STAT4 inducer. Thus, each effector Th cell produces cytokines without antigenic stimulation in response to an IL-1 family member and a specific STAT activator, implying an innate mechanism through which memory CD4 T cells are recruited by an induced cytokine environment.     

共刺激分子B7-1介导Th1/Th2免疫应答对日本血吸虫虫卵肉芽肿病变的影响

目的观察B7-1激发型mAb的体内注射对日本血吸虫感染小鼠Th1/Th2免疫偏移的影响及对虫卵肉芽肿病变的调节作用,探讨干预共刺激信号调控Th1/Th2免疫偏移控制血吸虫虫卵肉芽肿病变的新途径。方法小鼠感染日本血吸虫尾蚴后4w给予腹腔内注射B7-1激发型mAb,于6、8wk摘眼球取血收集血清,用ELISA双抗体夹心法测定血清中抗体IgGI、gG1I、gG2a的水平;同时取脾淋巴细胞培养72h,同法测定培养上清中细胞因子IFN-γ和IL-4的表达水平;并且检测感染小鼠虫卵肉芽肿体积。结果B7-1激发型mAb能显著下调感染小鼠血清IgG水平,并能显著上调IFN-γ的表达水平,下调IL-4的表达水平,同时能使虫卵肉芽肿体积显著减小。反映Th1/Th2免疫偏移的IgG1/IgG2a有下降趋势。结论B7-1激发型mAb能调节Th1/Th2免疫应答,诱导免疫反应向Th1方向偏移,从而为控制日本血吸虫虫卵肉芽肿病变的免疫治疗新途径提供了实验依据。     

日本血吸虫不同免疫原对小鼠Th1/Th2免疫偏移的影响

目的　观察单、双性日本血吸虫感染小鼠后Th1/Th2细胞因子水平的动态变化 ,探讨日本血吸虫不同免疫原对Th1/Th2免疫偏移的影响及与虫卵肉芽肿形成的相关性。方法　用ELISA夹心法检测单、双性日本血吸虫感染小鼠及单性感染 8w双性再感染 0～ 12w ,小鼠脾淋巴细胞培养上清Th1细胞因子IL - 2、IFN -γ和Th2细胞因子IL - 4表达水平。结果　单性感染小鼠 6～ 12w在脾淋巴细胞培养上清中可测出一定量的IL - 2和IFN -γ ,但无明显动态变化 ,而IL - 4未能测出 ;双性感染小鼠IL - 2和IFN -γ在感染后 4～ 6w开始上升 ,8w达高峰 ,随后下降 ,IL - 4则在感染后 8w时迅速上升且随着感染时间延长而明显升高 ,单性感染 8w双性再感染 4w时 ,小鼠脾淋巴细胞培养上清IL - 2、IFN -γ和IL - 4表达水平即迅速升高且在双性再感染 8～ 12w逐渐增强。结论　日本血吸虫不同免疫原对Th1/Th2免疫偏移的影响作用不同 ,Th1优势应答可能主要由虫体抗原诱导 ,Th2优势应答可能主要由虫卵抗原 (SEA)所诱导 ,后者是诱导宿主产生免疫病理反应的主要因素