Effect of murine malarial circulating immune complexes on the production of reactive oxygen species by peritoneal exudate cells of normal mice

Circulating immune complexes (CIC) isolated from sera of mice infected with Plasmodium berghei by precipitation with polyethylene glycol were examined for their ability to stimulate the production of reactive oxygen species by peritoneal exudate (PEC) of normal mice, using luminol-aided chemiluminescence (CL). CIC were found to be capable of stimulating the production of CL by normal mouse PEC. Weaker CL responses were observed when PEC were incubated with P. berghei soluble antigens. Normal mouse IgG and IgG1, IgG2b subclasses showed no effect on the stimulation of the production of CL. When normal mouse PEC were preincubated with CIC, their CL responses to opsonized zymosan were significantly depressed to 34% of the control level. The data suggest that CIC are capable of stimulating phagocytes to release reactive oxygen species and mediating pathological tissue damage.     

肿瘤坏死因子与疟性贫血

本文以化学发光法（ＣＬ）、诱化学发光法（ＩＣＬ）、红细胞变形性（ＥＤ）检测等方法研究了感染伯氏疟原虫ＡＮＫＡ株的ＢＡＬＢ／ｃ小鼠在注射重组肿瘤坏死因子（ｒＴＮＦ）以后发生严重疟性贫血时，其血浆中活性氧（ＲＯＳ）、相关自由基与ＥＤ及ＥＤ与疟性贫血间的关系。结果发现在严重疟性贫血时动物血浆中ＲＯＳ及相关自由基水平明显增高，ＥＤ明显降低。使用抗氧化剂可以明显改善上述过程而使血红蛋白（Ｈｂ）指数回升。因此认为，疟原虫感染时宿主体内过量肿瘤坏死因子（ＴＮＦ）的产生可使吞噬细胞释放大量ＲＯＳ及相关自由基，血浆中这类物质的大量聚集使红细胞变形能力受到破坏，这样，红细胞很易于被机体的红细胞清除系统所清除，这可能是疟性贫血发生和加重的又一主要途径。     

Elevated whole blood chemiluminescence in patients with systemic sclerosis

OBJECTIVE: Systemic sclerosis (SSc) is accompanied by oxidative stress that in turn may accelerate endothelium degeneration and thus disease progression. We tested whether phagocytes from SSc patients release more reactive oxygen species (ROS) and whether this release correlates with some clinical parameters. METHODS: ROS production by blood phagocytes was measured with the luminol enhanced whole blood chemiluminescence (CL). Resting and N-formyl-methionyl-leucyl-phenylalanine -induced CL (fMLP-induced CL) was measured in 30 patients with SSc and 30 healthy controls matched as to age, sex, and level of cigarette smoking. RESULTS: Resting CL and fMLP-induced CL calculated per 10(4) phagocytes present in the assayed blood sample were higher in patients with systemic sclerosis than in healthy controls (median; range, 0.88; 0.47-1.39 vs. 0.73; 0.13-1.07 aU/10(4)p and 621; 293-3522 vs. 411; 289-810 aUxs/10(4)p, p<0.02). Patients treated with cyclophosphamide and/or prednisone for 11; 3-168 months did not differ in respect to CL from those that never received the medications. Similarly, no significant differences were found between patients with limited and diffuse SSc. Resting CL correlated (p<0.05) with clinically manifested interstitial lung disease (r=0.59), single breath carbon monoxide diffusing capacity (r= -0.56) and serum autoantibodies titre (r= 0.43). CONCLUSIONS: Blood phagocytes from patients with systemic sclerosis, especially from those with interstitial lung disease, generate elevated amounts of ROS as assessed with CL. This confirms the presence of systemic oxidative stress in SSc patients.     

IL-12 eliminates the Th-2 dependent protective immune response of mice to larval Strongyloides stercoralis

The goal of the present study was to determine if immune-mediated killing of S. stercoralis L3 in mice could be modulated by shifting from a Th-2 to a Th-1 type immune response. L3 killing in immunized mice was ablated in CD4⁺ T cell-depleted animals, but not in CD8⁺ T cell-depleted or β2-microglobulin-deficient mice. Treatment of immunized mice with IL-4 or IL-5 neutralizing MoAb significantly reduced the protective effects of vaccination against S. stercoralis , while protective immunity was unimpaired in IFN-γ knockout mice. Recombinant IL-12 was administered to infected mice to switch the immune response from a Th-2 to a Th-1 type response. Protective immunity was ablated in immunized mice that received IL-12 therapy. Eosinophil numbers, eosinophil peroxidase levels, and parasite-specific IgG1 levels were lowered in IL-12 treated immunized animals, and parasite-specific IgG2a levels were increased in these animals. The data indicate that eosinophils are important as mediators of larval killing, and that the establishment of Th-2 type immunity results in killing of infective S. stercoralis L3, while a shift to Th-1 type immunity abrogates protective responses.     

IPSE/alpha‐1 of Schistosoma mansoni egg induces enlargement of granuloma but does not alter Th2 balance after infection

Schistosomiasis is a parasitic disease with more than 200 million people infected worldwide. The formation of granulomas around eggs trapped in the liver is the main cause of disease morbidity. Therefore, the aim of this investigation was to characterize the immunopathological response induced by the recombinant (r) IPSE/alpha‐1 egg protein in mice. Herein, we have shown that splenocytes from mice immunized with rIPSE/alpha‐1 produced IFN‐γ, TNF‐α, IL‐4, IL‐5 and IL‐13 characterizing a mixed Th1/Th2 type of immune response. Pathological analysis of the liver revealed that there was no alteration in the number of eggs and granulomas; however, we observed an increase in granuloma area in immunized mice. Furthermore, eosinophil peroxidase assay showed that there was no alteration in the eosinophil infiltration in the liver; however, n‐acetyl‐β‐glucosaminidase measurement revealed an increase in macrophage activity. Despite the alteration in the profile of liver inflammatory cells in rIPSE immunized mice, the production of chemokines such as CCL2, CCL3, CCL5 and CCL11 was unaltered compared with the control group. In conclusion, IPSE/alpha‐1 immunization induces a mixed Th1/Th2 type of immune response and enlargement of hepatic granuloma caused by an increased macrophage activity, but does not alter Th2 cytokines following infection.     

Phagocytosis and production of reactive oxygen species by peripheral blood phagocytes in patients with different stages of alcohol-induced liver disease: effect of acute exposure to low ethanol concentrations

BACKGROUND: In rodents, the development of alcoholic liver disease (ALD) after chronic alcohol feeding was shown to depend on the activity of enzymes that are necessary for production of reactive oxygen species (ROS) in phagocytes. The aim of this study was to determine the formation of ROS by resting and challenged phagocytes of patients with different stages of ALD in the presence of ethanol concentrations commonly found in the blood of alcohol abusers. PATIENTS AND METHODS: The release of ROS and the phagocytosis of bacteria by neutrophils and monocytes obtained from 60 patients, who were categorized in three groups due to the severity of ALD, were compared to that of 28 healthy controls. ROS release by these phagocytes was measured after challenging with endotoxin and the addition of ethanol (22 and 44 mM). RESULTS: Resting neutrophils but not monocytes from patients with severe stages of ALD produced significantly more ROS than those of healthy controls. Basal values of ROS production from neutrophils correlated closely to markers of the severity of ALD. ROS formation was depressed dose-dependently by ethanol in the healthy controls but not in alcohol abusers. CONCLUSIONS: Changes in the ROS metabolism of phagocytes found in this study might contribute to both the development of ALD and the impaired immune response occurring in patients with severe ALD.     

Effect ofAeromonas hydrophila enterotoxins on function of mouse phagocytes

Two enterotoxins produced byAeromonas hydrophila isolate SSU have been characterized in this laboratory. One is a cholera toxin cross-reactive cytolytic enterotoxin (CTC toxin) and the other is a non-cholera toxin cross-reactive cytotonic enterotoxin (non-CTC toxin). The two enterotoxins are capable of causing fluid accumulation in animal models; however, only the CTC toxin is lethal to mice and expresses hemolytic as well as cytotoxic activities. In this study, we have investigated the effects of these two toxins on mouse phagocytes. Four hours after intraperitoneal injection of a sublethal dose (460 g/kg of body weight) of CTC toxin, the chemiluminescence (CL) response of phagocytes in mouse blood was depressed significantly when compared with that observed for controls (intraperitoneal injection of only Hanks' balance salt solution, non-CTC toxin or before treatment with CTC toxin). When fresh whole blood was incubated with various concentrations (2.3, 11.5, 23, 230, 2300 ng/ml) of CTC toxin for 1.5 hr at 37° C, the CL response of blood phagocytes was reduced strikingly in a dose-dependent fashion; however, non-CTC toxin did not inhibit the CL response. The inhibitory effect induced by CTC toxin of the phagocytic function not only was abolished completely, but phagocytosis was enhanced in the presence of interferon-gamma (IFN-). In addition, IFN- alone induced the largest enhancement of the CL response in mouse phagocytes. These results demonstrated that CTC toxin inhibits the phagocytic ability of phagocytes eitherin vivo orin vitro and that IFN- pretreatment can overcome this toxic effect. The direct inhibitory effect on phagocytic activity by CTC toxin may be one of the pathological mechanisms associated with someAeromonas-mediated diseases, whereas IFN- may play a protective role for the host against these diseases.     

Impaired angiogenesis in glutathione peroxidase-1-deficient mice is associated with endothelial progenitor cell dysfunction

Several vascular disease are characterized by elevated levels of reactive oxygen species (ROS). Vascular endothelium is protected from oxidant stress by expressing enzymes such as glutathione peroxidase type 1 (GPx-1). In this study, we investigated the effect of vascular oxidant stress on ischemia-induced neovascularization in a murine model of homozygous deficiency of GPx-1. GPx-1-deficient mice showed impaired revascularization following hindlimb ischemic surgery based on laser Doppler measurements of blood flow and capillary density in adductor muscle. GPx-1-deficient mice also showed an impaired ability to increase endothelial progenitor cell (EPC) levels in response to ischemic injury or subcutaneous administration of vascular endothelial growth factor protein. EPCs isolated from GPx-1-deficient mice showed a reduced ability to neutralize oxidative stress in vitro, which was associated with impaired migration toward vascular endothelial growth factor and increased sensitivity to ROS-induced apoptosis. EPCs isolated from GPx-1-deficient mice were impaired in their ability to promote angiogenesis in wild-type mice, whereas wild-type EPCs were effective in stimulating angiogenesis in GPx-1-deficient mice. These data suggest that EPC dysfunction is a mechanism by which elevated levels of ROS can contribute to vascular disease.     

Alterations of tumor necrosis factor-alpha and interleukin 6 production and activity of the reticuloendothelial system in experimental obstructive jaundice in rats

BackgroundImmunological changes are well recognised in obstructive jaundice. The aim of this study was to monitor plasma tumor necrosis factor α (TNF-α) and interleukin-6 (IL-6) levels in rats with obstructive jaundice.MethodsThe ability of splenocytes and peritoneal exudate cells (PEC) to produce these cytokines both spontaneously and on induction with lipopolysaccharide (LPS), was compared in rats with and without obstructive jaundice (OJ). The activity of the reticuloendothelial system (RES) was also measured.ResultsSerum cytokine levels in OJ rats were higher than in control rats. PEC cultures produced significantly more IL-6, compared with control rats, declining thereafter. TNF-α activity in the splenocyte cultures of OJ rats was also higher than in the control group. Pronounced differences were found in the ability to produce TNF-α by PEC, i.e., TNF-α production was much stronger on day 7 in OJ rats than in controls. On day 14 TNF-α production was much lower and the spontaneous response was equal to the LPS-induced one. On day 21 the cells of OJ rats partially regained the ability to produce TNF-α RES activity of OJ rats was significantly suppressed in the liver and spleen, whereas the phagocytic activity in the lungs was elevated.ConclusionWe have demonstrated that the immune reactivity of OJ rats, intially elevated, underwent subsequent depression. The study also revealed a major effect of the operation alone on the studied parameters.     

T cell surface redox levels determine T cell reactivity and arthritis susceptibility

Rats and mice with a lower capacity to produce reactive oxygen species (ROS) because of allelic polymorphisms in the Ncf1 gene (which encodes neutrophil cytosolic factor 1) are more susceptible to develop severe arthritis. These data suggest that ROS are involved in regulating the immune response. We now show that the lower capacity to produce ROS is associated with an increased number of reduced thiol groups (-SH) on T cell membrane surfaces. Artificially increasing the number of reduced thiols on T cells from animals with arthritis-protective Ncf1 alleles by glutathione treatment lowered the threshold for T cell reactivity and enhanced proliferative responses in vitro and in vivo. Importantly, T cells from immunized congenic rats with an E3-derived Ncf1 allele (DA.Ncf1E3 rats) that cannot transfer arthritis to rats with an arthritis-associated Dark Agouti (DA)-derived mutated Ncf1 allele (DA.Ncf1DA rats) became arthritogenic after increasing cell surface thiol levels. This finding was confirmed by the reverse experiment, in which oxidized T cells from DA.Ncf1DA rats induced less severe arthritis compared with controls. Therefore, we conclude that ROS production as controlled by Ncf1 is important in regulating surface redox levels of T cells and thereby suppresses autoreactivity and arthritis development.     

Activation of phagocyte oxidative metabolism by opsonized Plasmodium falciparum merozoites

A luminol-dependent chemiluminescence (CL) method was used to measure the oxidative burst of phagocytes triggered by antimalarial antibodies and Plasmodium falciparum merozoites. A specific antibody-dependent increase in chemiluminescence response was obtained using both polymorphonuclear leukocytes and monocytes as effector cells. Using various sera from malaria infected subjects it was observed that antibodies involved in the increased chemiluminescence responses were encountered at higher levels in sera from protected subjects than in those susceptible to clinical manifestations. In the conditions used the assay shows substantial intertest variation but appears of interest to assess the protective status of groups of exposed individuals.     

Antibody response of Echinococcus granulosus infected mice: recognition of glucidic and peptidic epitopes and lack of avidity maturation

The antibody response was followed weekly during 68 weeks in 17 Balb/c mice intraperitoneally (i.p.) infected with 2000 Echinococcus granulosus protoscoleces (PSC) and in three mice i.p. immunized with 2000 dead PSC. Antibodies against hydatid cyst fluid (HCFA) and its peptidic (periodate-resistant) and carbohydrate (periodate-sensitive) epitopes were titrated by ELISA. Avidity and the antigen recognition pattern of antibodies were also analysed during infection and immunization by ELISA and immunoblot, respectively.
The antibody response of infected mice showed quantitative and qualitative variations during infection, since both titre as well as recognition of peptide and carbohydrate epitopes in HCFA depended on time post infection. No avidity maturation was evident during the course of infection. Sera from infected mice recognized the 38 kDa subunit of Ag5 but did not react with the 8 kDa subunit of AgB. On the contrary, the antibody response of immunized mice showed only one peak of antibodies that recognized both peptidic and carbohydrate epitopes of HCFA. In addition, sera from these mice recognized mainly 60 and 110 kDa bands. Our results suggest that: a) avidity and antigen recognition patterns of antibodies in mice treated with live PSC are different from those treated with dead PSC; b) antibodies against HCFA glucidic or peptidic epitopes appear at different times post infection.     

Regulation of Immune Response by Autogenous Antibody against Receptor

BALB/c mice repeatedly immunized with Pneumococcus R36A vaccine produce antibodies to phosphorylcholine having the TEPC-15 myeloma idiotype (murine IgA myeloma protein that binds phosphorylcholine). The plaque-forming cell response to phosphorylcholine shows a decrease with repeated immunizations. In contrast, spleen cells from multiply immunized mice responded better in vitro than spleen cells from nonimmunized mice. The serum of animals immunized four or five times agglutinates TEPC-15-coated sheep erythrocytes. Inhibition of hemagglutination shows that the agglutinating activity is directed against the TEPC-15 idiotype. Sera from these mice, when added to cultures of normal spleen cells, specifically suppress the response to phosphorylcholine. The suppressive activity in the serum can be removed by solid absorption with TEPC-15. Evidently, repeated immunization with antigen induces two kinds of antibody responses: one directed against antigen and the other directed against the antibody to the antigen. It is proposed that this "auto" antibody against receptor is involved in the regulation of the immune response.     

Differentiating between intra- and extracellular chemiluminescence in diluted whole-blood samples

Introduction: The differentiation between extra‐ and intracellular production of reactive oxygen species (ROS) in whole blood was measured by luminol‐ and isoluminol‐enhanced chemiluminescence (CL). Methods: Azide (total CL inhibition), azide + horseradish peroxidase (HRP, restoring extracellular CL), superoxide dismutase + catalase (depleting extracellular ROS) and HRP (enhancing extracellular CL) were used to modulate luminol‐ and isoluminol‐enhanced CL (10^?6–10^?3 m luminophores) of 125× diluted whole blood which was activated by both calcium ionophore A23187 (Ca‐I) and opsonized zymosan particles (OZP) separately. Results: Both activators stimulated intra‐ and extracellular production of ROS. Luminol‐enhanced CL of Ca‐I‐activated samples detected the intracellular ROS, and with the addition of HRP detected the extracellular CL as well. CL enhanced with isoluminol in concentrations of 10^?4 m or less was mostly extracellular. There was a mixture of intra‐ and extracellular CL in OZP‐activated samples, probably because of the ingestion of luminophore molecules. Conclusion: Measurement of Ca‐I‐activated CL enhanced with 10^?4 m luminol is recommended for the detection of intracellular ROS. The addition of HRP leads to the detection of overall ROS production while the OZP‐activated system with its addition of HRP can only be used to detect overall ROS production. Ca‐I‐activated CL enhanced with 10^?4 m isoluminol and with addition of HRP is recommended for the detection of extracellular CL.     

用日本血吸虫干卵建立体外肉芽肿反应模型

目的在体外建立一种与血吸虫感染宿主组织内病变相似的虫卵肉芽肿反应模型以便对该病变的形成机理作进一步研究。方法将日本血吸虫干卵悬液分别加于感染组、虫卵免疫组和正常对照组小鼠脾细胞培养物中，诱导这些脾细胞对虫卵的附着等反应，对影响反应强度的部分因素进行观察。结果感染组和免疫组的脾细胞反应均显著强于正常对照组者，感染组的反应较免疫组者更早出现且更显著。结论采用日本血吸虫干卵和感染鼠脾细胞在体外建立虫卵肉芽肿反应模型简便可行。     

Peritoneal cavity phagocytes from the teleost sea bass express a glucocorticoid receptor (cloned and sequenced) involved in genomic modulation of the in vitro chemiluminescence response to zymosan

To gain further insight into the role of cortisol in fish innate immune responses, we cloned and sequenced a 2592bp cDNA from sea bass (Dicentrarchus labrax) peritoneal leukocytes (PCLs) encoding a glucocorticoid receptor (DlGR1). The deduced aminoacid sequence displayed that DlGR1 belong to a multigenic family of steroid hormone receptors, and exhibited high homology (80%) to the Burton's mouth breeder (Haplochromis burtoni) HbGR1. The DlGR1 functional domains presented homologies with those of several vertebrate species. In situ hybridization assay revealed that DlGR1 was expressed in macrophages and neutrophils from the peritoneal cavity. Since in a previous paper, sea bass PCL chemiluminescence response (CL) has been related to increased respiratory burst of phagocytes stimulated with zymosan, PCLs, pre-incubated in vitro with cortisol at various concentrations, were assayed for their CL response. Dose-dependent cortisol inhibitory effects, and significant competitive activity of a low concentration of mifepristone (RU486), a glucocorticoid-receptor blocker, supported that cortisol-GR interaction was involved in modulating CL response via a genomic pathway. Results also indicated that cortisol could be effective through an additional not-genomic way, and showed that high doses of RU486 exerted an inhibitory effect on PCL chemiluminescence activity.     

Production of oxygen free radicals by phagocytes in patients on hemodialysis

In order to elucidate the vulnerability to infection in patients on chronic hemodialysis, as one of the host defense mechanisms, the production of oxygen free radicals by phagocytes was studied in patients by luminol- or lucigenine-enhanced chemiluminescence (CL). Whole blood CL of the patients, in both luminol- or lucigenine-enhanced was significantly higher than that in healthy adults after stimulation by zymosan, PMA, and Staphylococcus aureus (S. aureus) 209 P. However, the CL response of the patients' polymorphonuclear neutrophils (PMNs) with the same stimuli was slightly lower than that in healthy adults. There were no differences in the levels of opsonins, such as complements and immunoglobulins, between the patients and healthy adults. It appears that any factor in the patients' serum enhances CL response, because of the PMN CL response after addition of patients' serum was higher than that after addition of healthy controls' serum, and the PMN CL response after the addition of patients' serum obtained after hemodialysis was higher than that before hemodialysis. The addition of erythrocytes to PMNs from healthy adults caused a reduction in the PMN CL response, but the addition of urea and creatinine had no effect. The CL response induced by microsphere-bound luminol (lumisphere), which makes possible the direct measurement of highly reactive oxygen within phagosomes, was studied in the patients and controls. The CL response in the patients was slightly lower than those in controls, but not significant. These results suggest that not only CL response of phagocytes but also other defense mechanisms should be studied further to make clear the vulnerability to infection in these patients. In addition, the effect of three antibiotics, cefbuperazone, cefminox and latamoxef on luminol-enhanced CL of whole blood was studied in healthy adults and the patients. After 3-hour exposure to those drugs at subinhibitory concentration (1/4 MIC), Klebsiella pneumoniae (K. pneumoniae) 163 treated by drugs induced higher CL response of whole blood than that by untreated bacteria in both healthy adults and the patients, and the peak time of the CL response induced by the drug-treated bacteria was shorter than that by untreated bacteria. This study suggests that the three drugs at sub-MIC work in partnership with host defense against infection due to K. pneumoniae even in patients on chronic hemodialysis.     

The triggering of fibrinogen receptors on mononuclear phagocytes of healthy subjects and of a thrombasthenia Glanzmann patient promotes the generation of reactive oxygen species

The interaction of human fibrinogen (Fg) with homologous mononuclear phagocytes was investigated. Using a radioligand binding test, no evidence for high-affinity binding of either monomeric Fg, of the fibrin fragment E, or of radiolabelled Gly-Pro-Arg-Pro(-Try) to mononuclear phagocytes and myelomonocytic cell lines could be obtained, although commercial labelled Fg specifically bound to monocytes (MO), macrophages (M phi), U937 and HL60 cells. MO pretreated with either commercial or monomeric Fg and washed showed an oxidative burst upon treatment with anti-Fg antibodies, as evidenced by chemiluminescence (CL) measurement in the presence of luminol. The reaction depended on the Fg concentration used for pre-incubation, was divalent cation-independent and was inversely related to the time for which Fg was allowed to dissociate from the cell surface. Induction of the CL response required specific divalent antibodies, but not an intact Fc portion. MO pre-treated with fibronectin (Fn), washed and treated with anti-Fn antibodies exhibited no CL response. MO from a patient with thrombasthenia Glanzmann showed a similar reaction upon pre-incubation with Fg and stimulation with antibody. CL was also triggered by exposure of MO to surface-adsorbed Fg. The response was smaller than that induced by equivalent amounts of IgG, but was larger than that promoted by Fn. Pre-treatment of MO with ADP, fMLP or LPS did not enhance CL induced by surface-adsorbed Fg. Our results suggest that unstimulated mononuclear phagocytes of healthy subjects and of patients lacking the Fg receptors on platelets have receptors that bind the C-gamma-terminus of fibrin(ogen) with relatively low affinity, and that crosslinking of these receptors by surface-bound ligand promotes an oxidative burst but fails to induce cytokine secretion.     

Paraflagellar rod protein-specific CD8+ cytotoxic T lymphocytes target Trypanosoma cruzi-infected host cells

Our previous studies show that in mice immunized with the paraflagellar rod (PFR) proteins of Trypanosoma cruzi protective immunity against this protozoan parasite requires MHC class I-restricted T cell function. To determine whether PFR-specific CD8+ T cell subsets are generated during T. cruzi infection, potential CTL targets in the PFR proteins were identified by scanning the amino acid sequences of the four PFR proteins for regions of 8-10 amino acids that conform to predicted MHC class I H-2b binding motifs. A subset of the peptide sequences identified were synthesized and tested as target antigen in 51Cr-release assays with effector cells from chronically infected T. cruzi mice. Short-term cytotoxic T lymphocyte (CTL) lines specific for two of the peptides, PFR-1(164-171) and PFR-3(123-130), showed high levels of lytic activity against peptide-pulsed target cells, secreted interferon (IFN)-gamma in response to parasite-infected target cells, and were found to be CD8+, CD4-, CD3+, TCRalphabeta+ cells of the Tc1 subset. Challenge of PFR immunized CD8-/- and perforin-deficient (PKO) mice confirmed that while CD8+ cells are required for survival of T. cruzi challenge infection, perforin activity is not required. Furthermore, while lytic activity of PFR-specific CD8+ T cell lines derived from PKO mice was severely impaired, the IFN-gamma levels secreted by CTLs from PKO mice were equivalent to that of normal mice, suggesting that the critical role played by CD8+ T cells in immunity to the parasite may be secretion of type 1 cytokines rather than lysis of parasite infected host cells.     

Lack of interspecies barriers in anti–Id stimulated antibody production against Echinococcus granulosus antigens

Polyclonal human anti-hydatid antibodies were affinity purified from a hydatid patient serum and used to produce a rabbit anti-idiotypic serum. These anti-Id antibodies cross-reacted in ELISA with sera from 11 of 12 hydatid patients studied and with 13 infected or immunized mice sera. All mice primed and boosted with anti-Id produced anti-hydatid antibodies in the primary response and exhibited an increase in antibody titre after a booster injection. The same effect was observed with mice primed with antigen and boosted with anti-Id, although these mice exhibited higher antibody titres. A significant idiotype repertoire is shared by anti-hydatid antibodies produced by different individuals of the same or different species, and anti-Id raised against those antibodies behave as surrogate antigens producing a normal primary and secondary response in animals of different species from that used to isolate the Id.