Comparative studies on immune responses to infection in susceptible B10.BR mice infected with different strains of the murine nematode parasite Trichuris muris

A comparison of immune responses to infection between groups of B10.BR mice infected with different strains of T. muris , S strain (isolated in Sobreda, Portugal), E strain (isolated in Edinburgh), and E-J strain (originally E strain, which has been maintained in our laboratory, Japan), was performed. In mice infected with E and E-J strains, most of the worms were expelled by day 32 after infection, though the expulsion was faster in E-J strain-infected mice. In contrast, no expulsion was observed in S strain-infected mice by day 32 and egg production occurred on day 32. IL-4 production occurred in concanavalin A (Con-A)-stimulated mesenteric lymph node cells (MLNC) from B10.BR mice infected with E and E-J strains, whereas no IL-4 production was observed in S strain-infected mice. IL-4 production did not occur in normal mice. In comparison with normal mice, high levels of IFN-γ production by Con A-stimulated MLNC were detected in mice infected with every strain of  T. muris . IFN-γ production in S strain-infected mice was greater, occurred earlier and was more persistent than in mice infected with E and E-J strains. IgG1 and IgG2a antibodies to T. muris excretory/secretory antigens were observed in B10.BR mice infected with every strain of T. muris . Antibody production showed similar kinetics. These differences in the expulsion kinetics and IL-4 production in B10.BR mice infected with S, E, and E-J strains suggest the involvement of IL-4 in protection against T. muris infection, and confirm the previous conclusion by Else et al . (1994).     

Cellular immune responses and cytokine production in BALB/c and C57BL/6 mice during the acute phase of Angiostrongylus costaricensis infection

In our experimental study we were able to show that the contrasting outcome of Angiostrongylus costaricensis infection in C57BL/6 and BALB/c mice, in respect of morbidity and mortality, can be explained by divergent cellular immune responses and a different cytokine pattern in each strain. In BALB/c mice (i.e. those with high mortality), the initial high proliferation of ConA or LPS stimulated spleen cells dropped to very low levels after 2 weeks post-infection (p.i.), whereas in C57BL/6 mice (i.e. those with low mortality), only a minor reduction in lymphoproliferative responses after mitogenic stimulation was observed. The specific proliferation of spleen cells after stimulation with A. costaricensis adult worm antigen remained low in BALB/c mice throughout the experiment, but showed an augmented proliferation in C57BL/6 mice, especially from 2 weeks p.i. onwards. The mitogen-induced production of Th2-type cytokines (IL-4, IL-5, IL-6, IL-10) in spleen cell cultures remained low in BALB/c mice until 4 weeks p.i., but production of Th1-type cytokines (IL-2, IFN-gamma) was highly elevated at 14 and 28 days p.i. In C57BL/6 mice, an upregulated and balanced production of both Th1- and Th2-type cytokines was measured during the course of infection. In summary, a polarization of the immune response towards cellular hyporesponsiveness and a predominantly Th1 cytokine profile was observed in A. costaricensis infected BALB/c mice, which may contribute to pathogenesis and increased morbidity.     

Lymphocyte, antibody and cytokine responses during concurrent infections between helminths that selectively promote T-helper-1 or T-helper-2 activity

The injuence of Trichinella spiralis on infections with Trichuris murk was studied in non-responder B10. BR mice. Mice infectedonly with T. muris were unable to expel parasites and had many adult worms 35 days later. Infection with 300 larvae of T. spiralis, given seven or 14 (but not 28) days after T. muris, enabled mice to expel up to 90% of T. muris; expulsion of T. spiralis was not altered. Concurrently infected mice produced less T. murisspecijic IgG2a antibody than mice infected with T. muris only, andshowed higher proliferative responses when spleen and mesenteric lymph node cells were cultured in vitro with T. murk antigens. When T. spiralis was present mucosal mast cells were generated in T. muris-infected mice, whereas almost no mast cells were seen with only T. muris. Lymphocytes from doubly-infected mice produced significantly more interleukin 4 and 5 (IL-4, IL-5) and significantly less interferon-gamma (IFN-y) when stimulated in vitro with Concanavalin A (Con-A) than cells from mice infected with T. murk only. These data demonstrate that BI0.BR mice, which in single infections produce a Thl response to T. muris and develop no protective immunity, can mount a protective T-helper-2 (Th2) response and expel T. murk when concurrently infected with the ‘Th2 inducing’ nematode T. spiralis.     

刺激原诱导的华支睾吸虫感染大鼠淋巴细胞体外增殖和细胞因子的产生

目的　研究感染华支睾吸虫的大鼠T淋巴细胞对寄生虫抗原或促有丝分裂原植物血凝素刺激后的体外增殖及细胞因子产生的免疫效应。　方法　观察感染华支睾吸虫的大鼠脾淋巴细胞和肠系膜淋巴结细胞 ,在促有丝分裂原PHA ,华支睾吸虫分泌排泄抗原 ,华支睾吸虫成虫粗抗原和异尖线虫幼虫粗抗原刺激下 ,体外淋巴细胞增殖及细胞因子的水平 ,包括IFN γ ,IL 2 ,IL 4,IL 1 0。　结果　肠系膜淋巴结的淋巴细胞增殖高于脾淋巴细胞。淋巴细胞浓度为 3× 1 0 6或 9× 1 0 6 细胞/孔时 ,脾脏和肠系膜淋巴细胞增殖均显著高于对照组 (P <0 .0 1 )。淋巴细胞数为 5× 1 0 6 细胞 /孔 ,刺激原浓度为 5或 1 0 μg/ml时 ,淋巴细胞活化明显。肠系膜淋巴结细胞的细胞因子 ,IFN γ和IL 1 0的产生水平显著增加。　 结论　淋巴细胞浓度 5×1 0 6 细胞/孔和刺激原浓度 1 0 μg/ml的条件为激活T淋巴细胞增殖和细胞因子产生的最适培养条件。华支睾吸虫感染大鼠的成虫分泌排泄抗原在体内可能刺激淋巴细胞增殖和细胞因子产生     

Immunity to coccidiosis: genetic influences on lymphocyte and cytokine responses to infection with Eimeria vermiformis in inbred mice

Cellular and cytokine responses to infection with Eimeria vermiformis were compared in BALB/c (resistant) and C57BL/6 (B6-susceptible) inbred mice. Cellular responses in the mesenteric lymph node (MLN) occurred sooner after primary infection in the resistant BALB/c strain. In contrast, proliferative responses occurred earlier after challenge in B6 mice. Resting levels of CD4 + ve and CD8 + ve T-lymphocytes in the MLN differed between the two strains but the relative numbers of each subset remained relatively constant throughout primary infection. MLN cells taken at intervals after infection were assayed for release of the cytokines IFN-gamma, IL-5 and IL-10 after culture in vitro with the mitogen Concanavalin A (Con-A) or with parasite antigen. With either stimulus cells from resistant BALB/c mice released IFN-gamma and IL-5 earlier after infection than did B6 cells. The strains had a comparable absolute ability to produce IFN-gamma but BALB/c cells released more IL-5 than did B6, levels declining, rather than increasing, during primary infection in the latter. Only cells from BALB/c mice released IL-10 during infection. Cells taken after a secondary infection released relatively little cytokine after pulsing in vitro. These data suggest that the difference in response phenotype between the two strains when infected with E. vermiformis reflect a kinetic, rather than a qualitative, difference in ability to mount protective T-helper (Th) cell subset responses. No evidence was found for a Th2-mediated interference with ability to release IFN-gamma, the cytokine most closely associated with protective immunity.     

Fasciola hepatica infection downregulates Th1 responses in mice

Immune responses induced with helminth parasites have been extensively studied, but there is limited information on those to Fasciola hepatica, especially on the subtype of T cell induced with this parasite. We investigated the local and systemic T cell responses of different strains of mice following oral infection with doses of metacercariae from F. hepatica. Spleen cells from BALB/c and 129Sv/Ev mice given a low-dose (5 metacercariae) infection exhibited a Th2 response, producing high levels of the cytokines IL-4 and IL-5, and low levels of IFN-gamma and IL-2. In contrast, C57BL/6 mice showed a mixed Th1/Th2 response. A more marked polarization to a Th2 response was observed in BALB/c, 129Sv/Ev exposed to a high-dose (15 metacercariae) infection and the C57BL/6 mice also exhibited a clear Th2 response. IL-4 defective (IL-4-/-) C57BL/6 mice infected with 5 metacercariae produced less IFN-gamma and more IL-5 compared to their wild-type C57BL/6 counterparts, suggesting that IL-4 is important in establishing the Th2 type response in murine fasciolosis. However, the secretion of IFN-gamma and IL-2 was completely suppressed in the high-dose infection and this was also observed in IL-4-/- mice. Thus, liver flukes may secrete molecules that downregulate Th1 responses. T cell responses in the mesenteric (MLN) and hepatic lymph nodes (HLN) were also examined since newly excysted juveniles infect through the intestinal wall of their host before migrating to the hepatic tissue. Cells from both MLN and HLN secreted higher levels of IL-4 and IL-5 compared to spleen cells. We also observed a difference in cytokine profiles secreted by the MLN and HLN, which may reflect responses to antigens liberated by newly excysted juveniles and hepatic stage parasites, respectively.     

Correlations between worm burden and markers of Th1 and Th2 cell subset induction in an inbred strain of mouse infected with Trichuris muris

Helper T cell subset induction was examined within a single inbred strain of mouse ( B10.D2/n) where individuals varied in their ability to expel the nematode parasite Trichuris muris. In this mouse strain approximately half of infected individuals resist infection whilst half are unable to expel the parasite and harbour chronic mature adult worm infections. We here assess various T cell and serological parameters in individual B10.D2/n mice infected with T. muris in relation to the number of parasites harboured. Worm burdens showed very significant negative correlations with five different parameters indicative of the selective expansion within the host of helper T cells of the Th2 subset. Thus, in vitro IL-5 and 1L-9 production by restimulated mesenteric lymph node cells, totallgE levels, the early parasite-specific IgG1 response (all P < 0·01) and intestinal eosinophilia (P < 0·05), were all significantly negatively correlated with worm burden. In addition, levels of IL-3 were significantly greater in mice resistant to infection (P < 0·01). In contrast there was a significant positive correlation between worm burden and parasite-specific IgG2a levels (P < 0·05), IgG2a production being under the tight control of the Th1-specific cytokine IFN-y and thus a reliable marker for in vivo Th1 cell activation. The data demonstrates that an individual infected with T. muris is capable of mounting either a protective Th2-type response or an inappropriate Th1-type response. Thus, under conditions where host genetic factors and route of antigen introduction into the host are identical, polarized helper T cell responses can arise and hence may be due to a parasite-derived influence rather than an intrinsic difference between hosts per se.     

Protection in lambs vaccinated with Haemonchus contortus antigens is age related, and correlates with IgE rather than IgG1 antibody

The involvement of mucosal mast cells (MMC) in protection against infection with the murine nematode parasite Trichuris muris was studied in genetically mast cell-deficient WBB6F1-W/Wv mice and their normal littermates WBB6F1-+/+ mice. Expulsion of T. muris worms occurred in infected +/+ mice, whereas no worm expulsion was observed in infected W/Wv mice where the infection persisted until at least day 46 postinfection. No MMC responses were induced in either infected W/Wv or +/+ mice. Specific IgG1and IgG2a antibodies to T. muris excretory/secretory antigens were observed in infected W/Wv and +/+ mice, and antibody production showed similar kinetics. Interleukin 4 production by concanavalin A (Con A)-stimulated mesenteric lymph node cells (MLNC) was induced preferentially in infected +/+ mice. T. muris infection increased the levels of IFN-gamma produced by Con A-stimulated MLNC of infected W/Wv and +/+ mice, with the levels of IFN-gamma in infected W/Wv mice being higher than those in infected +/+ mice. Taken together, these results indicate that W/Wv and +/+ mice are susceptible and resistant to T. muris infection, respectively, and that MMC responses are not required for protective immunity.     

NK1.1+ cell depletion in vivo fails to prevent protection against infection with the murine nematode parasite Trichuris muris

Protection against the murine nematode parasite Trichuris muris has been shown to involve interleukin 4 (IL-4). NK1.1+ T cell receptor alphabeta+ cells, designated Natural Killer T (NKT) cells, produce a large amount of IL-4 in response to anti-CD3 stimulation and numerous pieces of evidence suggest that NKT cells provide the initial source of IL-4 for T helper 2 (Th2) priming. These observations allow the hypothesis that NKT cells produce a large amount of IL-4 in response to T. muris infection and augment Th2 responses and IL-4 production, thus achieving protection against T. muris. To investigate the involvement of NKT cells in protection against T. muris infection, NK1.1+ cell-depleted B10.BR mice were prepared by anti-NK1.1 monoclonal antibody injection. Efficient expulsion of T. muris worms occurred in NK1.1+ cell-depleted infected mice, and the expulsion kinetics of T. muris worms, the levels of IL-4 production by mesenteric lymph node cells, and the kinetics of the specific IgG1 and IgG2a responses to T. muris were similar to those in mouse IgG-treated or non-treated control B10.BR mice. These observations suggest that NK1.1+ cells and NKT cells are not involved in the induction of Th2 responses and protective immunity to T. muris infection.     

The role of IL-4, IL-13 and IL-4Ralpha in the development of protective and pathological responses to Trichinella spiralis

T helper type 2 (Th2) responses have been shown to be important in protective responses to gastrointestinal (GI) helminth infections and in the development of the intestinal pathology accompanying expulsion of the parasite. Different inbred mouse strains have been shown to develop different cytokine profiles following infection with GI helminths with increased resistance observed in those strains where Th2 cytokines predominate. The aim of this study was to determine the role of IL-4, IL-13 and IL-4Ralpha and the impact of host background on the development of the protective and pathological responses induced by infection with the gastrointestinal helminth Trichinella spiralis. IL-4, IL-13 and IL-4Ralpha were required for the generation of Th2 responses to T. spiralis; however, the role these responses play in the development of protection and enteropathy was less clear. IL-4Ralpha-deficiency mice resulted in substantially reduced parasite expulsion, intestinal pathology and Th2 responses. Similarly, lack of IL-13 resulted in inhibited expulsion and the development of enteropathy. Although Th2 responses were reduced in BALB/c IL-4-/- mice, neither expulsion nor enteropathy were different from wild-type mice. In contrast, C57BL/6 IL-4-/- exhibited delayed expulsion and reduced pathology, suggesting that host genetics are important in the function of individual cytokines. Thus, differences in background genotype may be an important component in the development host protection and the development of intestinal pathology accompanying the loss of GI helminths.     

In vitro indomethacin administration upregulates interleukin-12 production and polarizes the immune response towards a Th1 type in susceptible BALB/c mice infected with Leishmania mexicana

The immune response in Leishmania infected BALB/c mice is associated with a Th2 type cellular response, which has been characterized by the absence of interleukin (IL)-12, interferon (IFN)-gamma, and nitric oxide (NO) and the presence of IL-10 and IL-4. Prostaglandins (PGs) can modulate the immune response inhibiting the development of Th1 response and enhancing the development of Th2 response. We investigated the production of PGs and their effects on cytokine and NO production by spleen cells from Leishmania mexicana infected BALB/c and C57BL/6 mice. Increased production of PGs was noted as early as 1 week after infection in BALB/c mice, whereas in infected C57BL/6 mice PGs were not detected. In vitro administration of indomethacin (INDO), a specific inhibitor of PGs synthesis, reduced PGs production at normal levels, and increased IL-12, IFN-gamma, and NO production in infected BALB/c mice. Whereas, IL-10 and IL-4 were not affected. Moreover, INDO did not modulate cytokine and NO production in infected C57BL/6. INDO addition induced the intracellular killing of parasites in infected BALB/c mice. Together, these results suggest that suppression of PGs by INDO may promote the development of a protective Th1 type response in susceptible mice by a mechanism, which involves an enhancement of IL-12, IFN-gamma and NO production. These findings were confirmed by smaller lesions in BALB/c mice, when treated with INDO.     

Anti-IL-9 vaccination prevents worm expulsion and blood eosinophilia in Trichuris muris-infected mice

Production of neutralizing anti-IL-9 antibodies was induced in mice by immunization with mouse IL-9 coupled to ovalbumin. In the six mouse strains tested, a strong and long-lasting anti-IL-9 response developed with seric inhibitory titers of 10(-3) to 10(-5), as measured in an in vitro IL-9-dependent cell proliferation assay. In vivo, this immunization completely abrogated the increase in mast-cell protease-1 levels as well as the eosinophilia observed in mice after implantation of an IL-9-secreting tumor. We took advantage of this method to assess the role of IL-9 in infections with nematode Trichuris muris, where IL-9 production correlates with the resistant phenotype. C57BL/6 mice, which normally expel the parasite, became susceptible after anti-IL-9 immunization, demonstrating that IL-9 plays a critical role in this model. In addition, neutralization of IL-9 also inhibited parasite-induced blood eosinophilia. Taken together, the present data demonstrate the potency of our strategy to antagonize IL-9 in vivo and shows that this cytokine plays a major role in resistance against T. muris infection.     

Distinct roles of helper T-cell subsets in a systemic autoimmune disease

Imbalance of T-helper cell (Th) differentiation and subsequent cytokine dysregulation is implicated in inflammatory and autoimmune diseases. In particular, 2 cytokines produced by different Th cell populations, interferon-gamma (IFN-gamma) and interleukin-17 (IL-17), have been shown to play a critical role in autoimmunity. We have examined the roles of these cytokines in a mouse model of systemic autoimmunity resulting from the deletion of IL-2 in which autoimmune hemolytic anemia (AIHA) is a prominent feature. We demonstrate that, in IL-2-knockout (KO) BALB/c mice, elimination of the Th1 cytokine, IFN-gamma, delays the development of AIHA. Further, CD4(+) T cells from IL-2/IFN-gamma-KO mice produce elevated levels of IL-17 compared with wild-type (WT) and IL-2-KO, and these mice eventually develop intestinal inflammation. In contrast, elimination of the Th17 cytokine, IL-17, from IL-2-KO mice fails to suppress early acute AIHA development. These results suggest that in a systemic autoimmune disease with multiple manifestations, Th1 cells drive the early autoantibody response and IL-17-producing cells may be responsible for the more chronic tissue inflammation.     

Cellular immune responses of a Senegalese community recently exposed to Schistosoma mansoni: correlations of infection level with age and inflammatory cytokine production by soluble egg antigen-specific cells

A recently reported epidemic of Schistosoma mansoni infection in Senegal provided an opportunity to study the dynamics of the development of immunity to human schistosomiasis. We report here on the cell-mediated immune response in a population of 99 females and 95 males, with particular emphasis on the relationship between intensity of infection and age. We found that the intensity of infection correlated negatively with age in females but not in males. In men and women, both Th1- and Th2-type cytokines were detected upon in vitro stimulation of PBMCs with soluble egg antigen (SEA) or soluble adult worm antigens (SWAP). In the female group, SEA-induced PBMC proliferation was associated with the production of IFN-gamma, IL-2 and IL-5, all of which correlated negatively with intensity of infection. Most cytokine production correlated positively with age. Spontaneous production of TNF-alpha, IL-6 and IL-10 was higher in the infected population than in an uninfected control group. Our results suggest that immunity to infection could be more pronounced in the female population and associated with a Th0/1 + 2 pattern of cytokine secretion mediated by soluble egg antigen (SEA).     

Contrasting effects of Trichinella spiralis and Trichuris muris antigens on the infection by Leishmania infantum in BALB/c mice

The interaction of Trichinella spiralis and Trichuris muris derived antigens with the infection by Leishmania infantum was investigated in BALB/c mice. Infection with 10(6) promastigotes of L. infantum did not induce relevant serum antibody (IgG subclasses), nor cytokine (IFN-gamma, IL-4) responses despite that mice could partially control the infection. Immunization with T. spiralis activated a moderate IgG1 and secondarily an IgG2a anti-leishmanial response whereas immunization with T. muris elicited only a weak and late activation of IgG1 anti-leishmanial response. Immunization with T. muris caused an elevation of serum IFN-gamma levels which was drastically reinforced by the L. infantum infection, and that was accompanied by almost complete parasitological cure of infected mice. Immunization with T. spiralis induced an elevation of serum IL-4 levels but this response was greatly (about 60%) neutralized by the infection with L. infantum, and this was associated to exacerbation of the infection.     

Lack of galectin-3 involvement in murine intestinal nematode and schistosome infection

Many parasitic helminths produce large quantities of glycosylated proteins, some if which are believed to be involved in the skewing towards the dominant Th2 response observed during helminth infection. Galectin-3 is a member of a family of lectin-binding proteins produced by many different types of immune cells, including macrophages. Galectin-3 recognizes the GalNAcbeta1-4GlcNAc (LDN) epitope present on many helminth antigens, including those of the schistosome eggs. Here we show that galectin-3 is not involved in the development of the Th2 response nor in schistosome granuloma formation. Galectin-3-deficient mice were able to expel the gastrointestinal nematode Trichuris muris at the same speed as wild-type mice. Expulsion of T. muris is known to be dependent on a Th2 immune response and galectin-3-deficient mice showed no defect in their ability to produce Th2 cytokines or in their antibody responses, compared to wild-type mice. Furthermore, galectin-3-deficient mice were also able to mount a Th2 response to Schistosoma mansoni infection and they exhibited normal hepatic granuloma formation. The data presented here demonstrate that galectin-3 is not a critical component in the development of Th2 responses during helminth infection in vivo, nor is it essential for schistosome egg granuloma formation.     

Accumulation of eosinophils in intestine-draining mesenteric lymph nodes occurs after Trichuris muris infection

Eosinophils have recently been demonstrated capable of localizing to lymph nodes that drain mucosal surfaces, in particular during T helper 2 (Th2) responses. Resistance of mice to infection with the gastrointestinal nematode Trichuris muris depends critically on mounting of a Th2 response and represents a useful model system to investigate Th2 responses. Following infection of resistant BALB/c mice with T. muris, we observed accumulation of eosinophils in intestine-draining mesenteric lymph nodes (MLNs). The accumulation of MLN eosinophils was initiated during the second week of infection and peaked during worm expulsion. In contrast, we detected a comparably late and modest increase in eosinophil numbers in the MLNs of infected susceptible AKR mice. MLN eosinophils localized preferentially to the medullary region of the lymph node, displayed an activated phenotype and contributed to the interleukin-4 (IL-4) response in the MLN. Despite this, mice genetically deficient in eosinophils efficiently generated IL-4-expressing CD4(+) T cells, produced Th2 cytokines and mediated worm expulsion during primary T. muris infection. Thus, IL-4-expressing eosinophils accumulate in MLNs of T. muris-infected BALB/c mice but are dispensable for worm expulsion and generation of Th2 responses, suggesting a distinct or subtle role of MLN eosinophils in the immune response to T. muris infection.     

Increased production of interleukin 4 by CD4+ and CD8+ T cells from patients with tuberculosis is related to the presence of pulmonary cavities

In tuberculosis, cellular immunity is considered to be responsible for the eradication of infection but also for damage of host tissues. In animal models, the balance between Th1-type cytokines, especially interferon (IFN)-gamma, and Th2-type cytokines, primarily interleukin (IL)-4, seems crucial for these effects. Reports on Th1-type and Th2-type cytokines in human tuberculosis are conflicting, and little is known about their role in tissue damage. Flow-cytometric assessment of cytokine responses was performed in human immunodeficiency virus (HIV)-seronegative patients with active tuberculosis and in healthy controls. Patients and controls showed no significant difference in expression of IFN-gamma. However, patients showed a striking increase in production of IL-4 in CD4+ as well as CD8+ T cells. Most remarkably, the expression of IL-4 was especially elevated in patients with cavitary tuberculosis. The Th2-type response with increased production of IL-4 in patients with tuberculosis may antagonize host defense and lead to tissue necrosis.