bluuebunny/crossref_metadata_2025 huggingface dataset:
Variations in susceptibility to Leishmania amazonensis infection in lines of mice selected for high or low immunoresponsiveness
Authors: FALCOFF R. , BARRAL‐NETTO M. , STIFFEL C. , BOUTHILLIER Y. , BARRAL A. , FREITAS L.A. , MEVEL J.C. , MOUTON D.
Published: October 2007

Summary The degree of resistance to a local Leishmania amazonensis challenge has been compared in lines of mice obtained by selective breeding for high or low immunoresponsheness: High and Low antibody responder mice of Selections I and II (H1, H11 and L1 L11 lines) and high and low responder mice to T mitogen PHA (Hi/PHA and Lo/PHA). The aim of this preliminary study was to focus attention on genetic differences related with well defined immune characteristics. Clear‐cut results were obtained, both H1 and H11 mice developed large and disseminating lesions, the rale of symptom aggravation being faster in H11, while L1 and LM proved resistant to parasites, only small and transient lesions being observed for them during a 150 days follow up. The outcome of infection also differs in Hi/PHA and Lo/PHA mice, Hi/PHA having a resistant and Lo/PHA a susceptible phenotype.
Comparison between the MHC‐restricted antibody repertoire to Ascaris antigens in adjuvant‐assisted immunization or infection
Authors: CHRISTIE JACQUELINE F. , FRASER ELEANOR M. , KENNEDY MALCOLM W.
Published: October 2007

Summary Genetic restrictions to the immune repertoire will be an important consideration in the development of anti‐nematode vaccines. It has already been established that the major histocompatibility complex (MHC) limits responsiveness to nematode antigens in infection, but little is known of whether this also applies under other routes of sensitization, such as with adjuvants. The specificity of the antibody response was, therefore, compared in infection and adjuvant‐assisted immunization using secreted and somatic antigens of Ascaris suum as a model system in mice and rats. The findings were, first, that the lack of responsiveness to certain antigens in infection was not circumvented by Freund's adjuvant‐based immunization, despite the fact that the latter generally elicited higher levels of response. Secondly, that adjuvant‐assisted immunization could elicit responses to parasite products which were not detectable in the context of infection. Conversely, some specificities were detectable in infection but absent under adjuvant immunization. Finally, immunization with a defined parasite allergen (ABA‐1) in Freund's adjuvant did not provoke an IgE response which would be anticipated if the molecule were to have an intrinsic allergenic property. These results are likely to be of general importance to the application of subunit or recombinant vaccines against nematodiases and to the hypersensitivity reactions which vaccination might engender or recall.
In vivo activation of macrophages by IFN‐γ to kill Entamoeba histolytica trophozoites in vitro
Authors: GHADIRIAN ESFANDIAR , DENIS MICHEL
Published: October 2007

Summary To determine the role of interferon‐gamma (IFN‐γ) in the activation of macrophages to kill Entamoeba histolytica trophozoites in vitro, C57BL/6 mice were injected with various doses of recombinant IFN‐γ (rIFN‐γ) by either the intravenous, intraperitoneal or intramuscular routes. Mice were treated with doses of rIFN‐γ ranging from 101 to 105 units. Twenty hours later, peritoneal macrophages were harvested from the treated animals. Macrophage monolayers were prepared and their in vitro cytotoxic activity against a virulent strain of E. hystolytica (IP:0682:1) was determined. Amoebicidal activity was determined by counting the number of dead trophozoites by Trypan Blue exclusion in cultures containing macrophages and amoebic trophozoites which were incubated together for 4 h. Both intravenous and intraperitoneal treatment resulted in the recovery of macrophages from the peritoneal cavity which exhibited amoebicidal activity in vitro. Peritoneal macrophages harvested from mice that had been treated intraperitoneally or intravenously with rIFN‐γ, however, showed significantly more amoebicidal activity in comparison to macrophages harvested from animals treated intramuscularly. There was a dose dependent relationship between the concentration of rIFN‐γ used to activate macrophages in vivo and the number of dead trophozoites in vitro. In addition, these results confirm our previous observations that treatment in vitro with rIFN‐γ can activate murine peritoneal macrophages to kill amoebic trophozoites.
Detection of cytokine mRNA in the brains of mice with toxoplasmic encephalitis
Authors: HUNTER C.A. , ROBERTS C.W. , MURRAY M. , ALEXANDER J.
Published: October 2007

Summary C57B1/10 ScSn mice infected with Toxoplasma gondii developed a meningoencephalitis, characterized by areas of tissue destruction and cellular infiltration including foci of neutrophils. Large numbers of cyst stages were found throughout the brain but were not always associated with inflammation. The use of immunocytochemistry to detect glial fibrillary acidic protein, an astrocyte specific marker, showed a widespread astrocyte activation. This was particularly prominent in areas of intense inflammation but cysts were negative for glial fibrillary acidic protein, indicating that astrocytes were not host cells for the bradyzoites. The use of the polymerase chain reaction to assist in the amplification of total brain RNA allowed the characterization of the cytokines being produced locally within the brains of infected animals. β‐ actin transcripts were detected in all of the uninfected and infected mice. In only one of the seven uninfected control mice were other transcripts found. Transcripts for tumour necrosis factor‐α, interleukin‐1α and β, interleukin‐6, macrophage inflammatory protein‐1 and interferon‐γ as well as the CD4 marker were detected in all of the infected mice. However, transcripts for IL‐2 and IL‐4 were not present. Several of the cytokines present are capable of initiating meningeal inflammation and may play a role in the immunopathogensis of toxoplasmic encephalitis.
Effects of recombinant tumour necrosis factor on antibody‐dependent eosinophil‐mediated damage to Schistosoma japonicum larvae
Authors: JANECHARUT TUENTA , HATA HIDEKAZU , TAKAHASHI HIDENORI , YOSHIDA SHOJI , SAITO HIROSHI , KOJIMA SOMEI
Published: October 2007

Summary Human recombinant tumour necrosis factor (rTNF) enhanced monoclonal IgE‐dependent eosinophil‐mediated cytotoxicity to schistosomula of Schistosoma japonicum in a dose‐dependent manner. The enhancing effect of rTNF was also observed for the antibody‐dependent cytotoxicity of a human eosinophilic leukemia cell line, EoL‐3, but not of another cell line, EoL‐1. Observation by a slow‐motion movie camera demonstrated that activated EoL‐3 cells adhered to the surface of schistosomula by 6 h after incubation, which triggered intracellular movement of eosinophil granules. The granules were concentrated toward the surface of the larvae and then degranulation started. The cell membrane was left as a balloon‐like remnant. Cell sorting analysis by FACStar indicated that the expression of receptors for C3bi (CR3) and low affinity FcR for IgE (FceRII) increased on the surface of EoL‐3 cells after stimulation with rTNF, while this was not observed for EoL‐1 cells.
Vaccination of young Dorset lambs against haemonchosis
Authors: TAVERNOR ANGELA S. , SMITH TREVOR S. , LANGFORD CORDELIA F. , MUNN EDWARD A. , GRAHAM MARGARET
Published: October 2007

Summary Six Dorset Horn lambs were each vaccinated at age 7 weeks and 9 weeks with 50 μg of glycosylated integral membrane proteins, particularly enriched in the protein H11 from the intestinal brush border of adult Haemonchus. At 11 weeks of age the lambs were infected with 10 000 infective third stage Haemonchus larvae. Compared with the average for the control group the vaccinated group of lambs had a 78% reduction in parasite egg output over the patent period, with four of the six better than 93% protected. At autopsy 35 days post‐infection the mean total worm burden of the vaccinated lambs was 83% reduced compared with the controls. The serum antibody titres to H11 correlated with the degree of protection.
Comparative study of the antigenic composition of oocyst isolates of Cryptosporidium parvum from different hosts
Authors: NINA J. M. S. , McDONALD V. , DEER R. M. A. , WRIGHT S. E. , DYSON D. A. , CHIODINI P. L. , McADAM K. P. W. J.
Published: October 2007

Summary An investigation was made of the antigenic composition of oocyst isolates of Cryptosporidium parvum by immunoblotting using rabbit polyclonal or murine monoclonal antibodies (MoAbs) developed against this parasite. Using the polyclonal antibodies in blots, a common antigenic profile was obtained from a number of human oocyst isolates from AIDS patients and immunocompetent children in the UK and Portugal. Antigenic differences were observed, however, between a human isolate from Turkey and these other human isolates. The antigenic profilies of oocyst isolates from deer and cattle were similar, but the profiles of the animal and human isolates differed to some extent. Two MoAbs which, in immunofluorescence microscopy, reacted with the surface of the C. parvum sporozoite were also used in blots. A major antigen(s) from 9 of 11 human oocyst isolates recognized by these MoAbs had a molecular weight of 47 kD, but the sizes of the corresponding antigens of the remaining 2 human isolates, one from Turkey (same as above) and one from the UK, were 45–5 and 51 kD, respectively. The equivalent antigen(s) from 4 bovine and 4 ovine isolates was 48 kD. One of the MoAbs failed to react in blots with 2 of the isolates, 1 human and 1 bovine.
Distinction of human hookworm larvae based on lectin‐binding characteristics
Authors: KUMAR SANJEEV , PRITCHARD DAVID IDRIS
Published: October 2007

Summary A comparative study of lectin binding to ensheathed (EnL3) and exsheathed (ExL3) L3 larvae of Necator americanus, Ancylostoma duodenale and Ancylostoma ceylanicum revealed a number of differences between these hookworm species. These differences could provide a novel approach to distinguish infective L3 larvae in field conditions. For example, binding of Ulex europaeus agglutinin (UEA) and Ricinus communis agglutinin (RCA/20) to N. americanus EnL3 distinguished them from those of A. duodenale and A. ceylanicum. Furthermore, UEA and RCA/20 negative EnL3 could be separated into the two Ancylostoma sps. tested, as Dolichos biflorus agglutinin and Soybean agglutinin bound to EnL3 of A. ceylanicum but not to those of A. duodenale.
Testosterone‐unresponsiveness of existing immunity against Plasmodium chabaudi malaria
Authors: WUNDERLICH FRANK , BENTEN W. PETER M. , BETTENHAEUSER UTE , SCHMITT‐WREDE HANS‐PETER , MOSSMANN HORST
Published: October 2007

Summary Testosterone (Te) is known to suppress immunity and to increase host susceptibility to many parasites. This study investigates the action of Te on immunity acquired against blood‐stages of the malaria parasite Plasmodium chabaudi in female mice of the inbred strain C57BL/10. Our data show: (i) About 90% of mice infected with 106 P. chabaudi‐infected erythrocytes are able to develop protective immune mechanisms which become evident in self‐healing the infection. The capability of self‐healing is lost when mice are pretreated with Te for 3 weeks. (ii) Mice which have self‐healed infections acquire immunity to homologous rechallenge. Concomitantly, mice become Te‐unresponsive in that their acquired immunity is not suppressible by Te‐treatment. (iii) Flow cytometry reveals that Te‐pretreatment entails an increase of CD8+ cells and a decrease of Ig+ cells by about 4% in spleens of non‐immune mice. In immune mice, however, there is a Te‐unresponsiveness of the percental distribution of splenic cell populations. (iv) Adoptive transfer experiments indicate that immunity is conferred by spleen cells, presumably non‐T‐cells. These cells are Te‐unresponsive, since they exert their effect in Te‐pretreated mice in the presence of Te. (v) Teunresponsive immunity can be also transferred by serum, especially the IgG‐fraction, obtained from immune mice. Our data demonstrate that Te prevents the development of protective immunity against P. chabaudi infections. However, when once established, protective immunity becomes unresponsive to Te. Our data suggest that the effector mechanisms of protective immunity involve Teunresponsive B cells secreting protective IgG‐antibodies.
Extracts of mosquito salivary gland inhibit tumour necrosis factor alpha release from mast cells
Authors: BISSONNETTE ELYSE Y. , ROSSIGNOL PHILIPPE A. , BEFUS A. DEAN
Published: October 2007

Extracts of salivary glands of the yellow fever mosquito Aedes aegypti inhibit tumour cell‐stimulated release of tumour necrosis factor alpha (TNFα) from rat mast cells, but do not inhibit antigen‐induced histamine secretion. This inhibitory activity for TNFα is found in salivary glands of female but not in male mosquitoes. This inhibition is not mediated by bacterial contamination (LPS), by calcitonin gene related peptide (CGRP), nerve growth factor (NGF), epidermal growth factor (EGF) or transforming growth factor β (TGFβ). The factor(s) has a molecular weight > 10 kDa and is neutralized by boiling for 10 min or heating at 56°C for 30 min. The modulation of this proinflammatory mediator, TNFα, produced by mast cells in sites of blood feeding may facilitate completion of the blood meal, and as reported for certain vector‐transmitted parasites, may enhance infectivity.
Mice immunized with a synthetic peptide construct corresponding to an epitope present on a Plasmodium falciparum antigen are protected against Plasmodium chabaudi challenge
Authors: LORD ROGER , JONES GRAHAM L. , SPENCER LISA , SAUL ALLAN
Published: October 2007

Inhibitory monoclonal antibody (MoAb) 8E7/55 recognizes a parasitophorous vacuole membrane (PVM) antigen in Plasmodium falciparum. Previous studies have identified the epitope, DNNLVSGP, recognized by the MoAb. A synthetic peptide containing this sequence was synthesized and coupled to diphtheria toxoid (DT) and was found capable of generating antibodies when used as an immunogen in mice which recognize the native antigen exp‐1. In this study we demonstrate the ability of the MoAb and antisera generated against the peptide construct to recognize a 54 kD PVM antigen in Plasmodium chabaudi. The P. chabaudi antigen is synthesized in trophozoites and released to the surrounding culture media outside the parasitized erythrocyte. Mice immunized with the peptide conjugate are protected when challenged with a lethal strain of P. chabaudi. Protection in the mice correlated with the antibody titre prior to challenge. If the PVM antigen from P. chabaudi is a homologue of exp‐1 from P. falciparum, then these experiments may provide a guide to the antibody titres required in human trials before antibody mediated protection could be expected. The discovery that a PVM localized antigen is secreted into the surrounding in vitro culture media provides us with a valuable model system for further investigation of protein trafficking pathways in malaria‐infected erythrocytes.
Murine tumour necrosis factor plays a protective role during the initial phase of the experimental infection with Trypanosoma brucei brucei
Authors: MAGEZ STEFAN , LUCAS RUDOLF , DARJI AYUB , SONGA EMMANUEL BAJYANA , HAMERS RAYMOND , BAETSELIER PATRICK DE
Published: October 2007

Soluble extracts from salivarian trypanosomes (Trypanosoma brucei brucei, T. evansi and T. congolense) were shown to be capable of inducing murine tumour necrosis factor (mTNF) secretion, both in vivo and in vitro, whereas the soluble extract of an intracellular trypanosome (T. cruzi) failed to do so. Furthermore, the role of mTNF during the initial phase of experimental infections with T. brucei was studied by treating infected mice with mTNF‐inducing trypanosoma soluble extract and with neutralizing monoclonal anti‐mTNF antibodies. Treatment of the infected animals with different doses of T. brucei soluble extract resulted in a lower first parasitaemia peak (low lysate dose) and in a longer survival time or in a nearly total inhibition of parasite development (high lysate dose). Cotreatment of the infected mice with both anti‐mTNF antibodies and a high dose of soluble extract completely restored the parasite development in both trypanosusceptible C3H/He mice and trypanosubtolerant CBA/Ca mice, indicating a protective role of mTNF during the parasitaemia. Collectively these results suggest a negative influence of mTNF on T. brucei development in vivo.
Different susceptibility to the IL‐3 induced‐protective effects between Strongyloides ratti and Nippostrongylus brasiliensis in C57BL/6 mice
Authors: ABE TATSUYA , SUGAYA HIROKO , YOSHIMURA KENTARO
Published: October 2007

Repetitive administration of recombinant IL‐3 induced protection against Strongyloides ratti but not against Nippostrongylus brasiliensis in C57BL/6 mice. Numbers of S. ratti were negligible from day 4 to day 6 post‐infection in mice injected with IL‐3, whereas N. brasiliensis burdens were almost equal from day 4 to day 6 between mice injected with IL‐3 or with medium. Mice treated with IL‐3 and then concurrently infected with S. ratti and N. brasiliensis were protected from intestinal S. ratti but not from N. brasiliensis. The numbers of intestinal mucosal mast cells were increased by the repetitive IL‐3 treatment on one day after the final injection and was augmented by subsequent infection with both nematodes.
The role of OX22− helper T cells in protective immunity to reinfection with Taenia taeniaeformis in rats
Authors: ASANO KAZUHITO , ITO AKIRA , OKAMOTO KEN‐ICHI
Published: October 2007

Spleen cells (SpC) and mesenteric lymph node cells (MLNC) from F344 donor rats actively immunized by oral inoculation with Taenia taeniaeformis eggs were syngeneically transferred into previously uninfected recipient rats by intravenous injection. Recipient rats were challenged with eggs after cell transfer. The degree of immunity was assessed by counting the number of growing metacestodes (MC) in the liver and compared with that in controls. Transfer of 2 × 108 SpC, obtained from donors immunized for ten or more (but not for three or five) days before cell transfer inhibited the establishment of most of MC. There were approximately 86–88% reductions in MC recoveries. SpC (2 × 108) obtained from donors immunized for ten days inhibited the establishment of most of MC in recipient rats when transferred nought, two, or 24 h (but not 48 h) before egg challenge. Functional cells in the immune SpC were helper T cells W3/25+, OX8− and OX22−. However, immune MLNC obtained from donors immunized for three to ten days before cell transfer had no effect on transferring immunity.
Characterization of allergens of the cat flea, Ctenocephalides felis: detection and frequency of IgE antibodies in canine sera
Authors: GREENE W. K. , CARNEGIE R. L. , SHAW S. E. , THOMPSON R. C. A. , PENHALE W. J.
Published: October 2007

Flea allergens, fractionated by polyacrylamide gel electro‐phoresis and transferred to nitrocellulose, were identified using 20 flea‐allergic dog sera in an enhanced chemilumi‐nescent assay for canine IgE antibodies. At least 15 different flea components in the molecular weight range of 14–150 K bound IgE and every serum demonstrated a different pattern of binding. Three of the components with apparent molecular weights of 25, 40 and 58 K were each bound by at least 40% of the sera. No reactivity was seen when normal dog sera were used. These results demonstrate a greater number of flea allergens and a far greater diversity of the IgE antibody response to flea allergens than has previously been described, and suggest that immediate hypersensitivity may be an important mechanism in the pathogenesis of canine flea allergy.
Characterization of epitopes on a 32 kDa merozoite surface protein of Theileria sergenti
Authors: ZHUANG WEN ZHONG , KUBOTA SHUICHI , SUGIMOTO CHIHIRO , ONUMA MISAO
Published: October 2007

Epitopes on a 32 kDa protein, which is an immunodominant major surface protein ofTheileria sergenti, recognized by anti‐merozoite monoclonal antibodies were characterized. The results of a competetive binding assay between monoclonal antibodies indicated that there were at least three epitopes in this protein. The presence of repeated epitopes was suggested by using two‐site enzyme‐linked immunosorbent assay. The protein was partitioned into the detergent phase of Triton X‐114 extracts, indicating that the 32 kDa protein is an integral membrane protein. Periodate treatment of 32 kDa protein implies that one epitope of the epitopes recognized by monoclonal antibody has a carbohydrate moiety.
Antigenic variants of Plasmodium chabaudi chabaudi AS and the effects of mosquito transmission
Authors: BRANNAN L. R. , McLEAN S. A. , PHILLIPS R. S.
Published: October 2007

Previous results, using a passive transfer assay, have shown that recrudescences of Plasmodium chabaudi chabaudi AS strain are antigenically different from the infecting parental population and also that the recrudescence appears to be a mix of antigenic types. This present study examines further these recrudescent populations using an indirect fluorescent antibody test on live, schizont‐infected red blood cells. This analysis shows that ten clones derived from a recrudescence are all antigenically different from the parent population and that some are different from each other. The use of this method to examine the antigenic types of recrudescent clones after transmission through mosquitoes also demonstrates a resulting change in antigenicity. Such results showing a link between mosquito transmission and varying antigenicity may have important implications in terms of immunity and vaccine development.
The immunogenicity of hookworm (Necator americanus) acetylcholinesterase (AChE) in man
Authors: BROWN ALAN , PRITCHARD DAVID IDRIS
Published: October 2007

A number of different but complementary approaches have been used to demonstrate the immunogenicity of Necator americanus acetylcholinesterase to infected individuals. Western blotting of parasite somatic extracts with human post‐infection sera and a specific rabbit antiserum to AChE resulted in the development of almost identical antigen‐recognition profiles. AChE‐containing fractions produced by preparative iso‐electric focusing were subsequently shown to be antigenic in ELISA using post‐infection sera. This preliminary data was reinforced by the affinity‐purification of AChE by immobilized post‐infection IgG, and the immunoprecipitation of AChE activity from ES by post‐infection IgG. Finally, AChE purified by affinity chromatography on edrophonium chloride was shown to be antigenic by Western blotting, and in ELISA, against post‐infection sera, although a degree of re‐activity was also seen with normal human sera. This data is discussed in the context of the host‐parasite relationship.
Protective immunity and mast cell and eosinophil responses in mice infested with larval Haemaphysalis longicornis ticks
Authors: USHIO HIROKO , WATANABE NAOHIRO , KISO YASUO , HIGUCHI SEIICHI , MATSUDA HIROSHI
Published: October 2007

WBB6F1 ‐+‐ /+ mice were infested with larval Haemaphysalis longicornis ticks twice at an interval of 14 days: apparent resistance against ticks was expressed in the second infestation. The first infestation induced degranula‐tion of a small number of mast cells at the feeding sites within 6 days, and resulted in two‐fold increases of mast cell numbers on day 14 with a significant elevation of total immunoglobulin E (IgE) levels in sera and high proportion of IgE‐bound mast cells. The second infestation resulted in the intensive degranulation of the increased mast cells at the feeding sites. Eosinophils infiltrated into the feeding sites of ticks: the second infestation led to a greater maximal level of the infiltrating eosinophils. These data suggest that the resistance against larval H. longicornis ticks in mice may be expressed as a result of immediate hypersensitivity and many eosinophils infiltrating from the blood to the feeding sites might contribute to the tick rejection.
Tumour necrosis factor and interleukin‐6 production induced by components associated with merozoite proteins of Plasmodium falciparum
Authors: JAKOBSEN P. H. , MOON R. , RIDLEY R. G. , BATE C. A. W. , TAVERNE J. , HANSEN M. B. , TAKACS B. , PLAYFAIR J. H. L. , MCBRIDE J. S.
Published: October 2007

P. falciparum merozoite antigens, merozoite surface protein‐l (MSP‐1) and rhoptry associated protein‐1 (RAP‐1), were shown to be liberated into the supernatant of in vitro parasite cultures and to be included in the endotoxin‐like exoantigen complex, previously designated Ag7. Material affinity purified from culture supernatants, using immobilized monoclonal antibodies specific for RAP‐1 or MSP‐1, stimulated normal human mononuclear cells to produce TNF and IL‐6 in vitro. However, stimulation of TNF was absent, and that of IL‐6 was reduced, when the antigens were purified from detergent extracts of infected erythro‐cytes. These results indicate that the RAP‐1 and MSP‐1 proteins themselves do not stimulate the production of TNF. Instead, other components associating with these exoantigens may be responsible for the TNF production. Mouse antisera blocking TNF production stimulated by P. yoelii exoantigens also blocked TNF production stimulated by material affinity purified from P. falciparum culture supernatants using RAP‐1 specific monoclonal antibody, indicating the conserved structure of the TNF inducing component.
Protective CD4+ T‐cell lines raised against Plasmodium chabaudi show characteristics of either Th1 or Th2 cells
Authors: TAYLOR‐ROBINSON ANDREW W. , PHILLIPS R. STEPHEN
Published: October 2007

Splenic T‐lymphocyte lines were established in vitro from Plasmodium chabaudi‐infected NIH mice on days 16 and 20 of a primary infection, and from mice after two or three infections. Each line responded specifically to stimulation with a lysed soluble extract of P. chabaudi‐infected erythrocytes (pRBC), and displayed a CD4+ (L3T4+) surface phenotype. Both the day 16 and 20 cell lines, when stimulated in vitro, secreted interleukin‐2 (IL‐2) and γ‐interferon (IFN‐γ), indicative of their belonging to the T helper 1 (Th1) CD4+ subset. In contrast, both lines derived from reinfected mice secreted interleukin‐4 (IL‐4) and provided helper activity in antibody production to P. chabaudi in vitro, and thereby had the characteristics of Th2 cells. All four T‐cell lines provided significant protection to naïve mice infected with P. chabaudi. In immuno‐compromised mice, the day 16 T‐cell line was as protective as in naïve mice whereas the cell line from mice infected twice required the additional transfer of mature naïve splenic B cells to provide protection comparable to that seen in the immunocompetent naïve recipients. The results establish that protective immunity to P. chabaudi may be associated with the induction of CD4+ Tcells of either the Th1 or Th2 subset which confer protection against this malaria parasite by mechanisms independent of, and dependent upon, B‐cell involvement, respectively.
Modulation of the allergic reactivity of slum children by helminthic infection
Authors: HAGEL ISABEL , LYNCH NEIL R. , PÉREZ MIREYA , PRISCO MARIA C.DI , LÓPEZ REINA , ROJAS EDWARD
Published: October 2007

Infection by helminthic parasites can cause the polyclonal stimulation of IgE synthesis, possibly via an enhanced production of interleukin‐4 (IL‐4), and this has been suggested to influence the allergic reactivity of tropical populations where these parasites are endemic. We evaluated a group of urban slum children in Caracas, Venezuela, with a high prevalence of helminthic infection (70.8%), to establish the relationship between the elevated IgE levels (3696 IU/ml) induced by these parasites and various aspects of the allergic response. Although the absolute levels of IL‐4 detected in the sera of these children were low (0.65 ± 0.20 ng/ml), a strong positive correlation (r = 0.78) was found between these and serum IgE. The cutaneous immediate hypersensitivity reactivity to extracts of common environmental allergens was relatively low (17.5% to house dust), although that to Ascaris extract was moderately high (49.4%). Significant inverse correlations were found between total IgE levels and the different skin test reaction diameters, including Ascaris. The positivity of Prausnitz‐Kustner passive transfer tests was low in this group (34%), with a strong inverse correlation (r= ‐0.75) being found between this and total IgE levels. Significant inverse correlations were also found between total IgE levels and specific IgE antibody to environmental allergens, and to Ascaris antigen. We suggest that the polyclonal production of IgE stimulated by helminthic infection can suppress the allergic response to environmental and parasite allergens via both mast cell saturation and inhibition of specific IgE production.
The schistosomulicidal activity and the production of IL‐1 and TNF‐α by peritoneal macrophages from infected mice and their potentiation by muramyl tripeptide‐phosphatidyl ethanolamine (MTP‐PE) treatment
Authors: SEGER M. , GOLD D. , LENGY J. , PAULI H. , KEISARI Y.
Published: October 2007

Production of TNF‐α and IL‐1 by adherent peritoneal exudate macrophages (APEM) was monitored for 20 weeks in Schistosoma mansoni infected mice in comparison to their schistosomulicidal activity. LPS‐triggered IL‐1 and TNF‐α production by APEM peaked 10 weeks post infection (p.i.) and declined thereafter. The schistosomulicidal activity of APEM also peaked after 10 weeks but remained elevated thereafter. Infected mice were also treated with the immunostimulator liposomal muramyl tripeptide‐phosphatidyl ethanolamine (MTP‐PE) 6 or 10 weeks p.i., and their APEM were tested 4 weeks later. APEM from such treated animals showed elevated IL‐1 and TNF‐α production when treatment commenced 6 weeks p.i., while their schistosomulicidal activity increased when treatment commenced either 6 or 10 weeks p.i. The L‐arginine inhibitor, NG monomethyl arginine, markedly inhibited the schistosomulicidal activity but not the IL‐1 and TNF‐α production of APEM. Our results show that monokine production increases during the acute phase of infection and declines during its chronic phase, while macrophage schistosomulicidal activity remains constant throughout. Furthermore, TNF‐α or IL‐1 may play a minor role in APEM mediated killing of schistosomula.
Immunological relationships during primary infection with Heligmosomoides polygyrus (Nematospiroides dubius): parasite specific IgG1 antibody responses and primary response phenotype
Authors: WAHID F. N. , BEHNKE J. M.
Published: October 2007

IgG1 antibody responses to Heligmosomoides polygyrus were measured in eight mouse strains supporting acute (< 8 weeks, SJL, SWR), intermediate (10–20 weeks, NIH, BALB/c) or chronic (> 25 weeks, C57BL/0, CBA, C3H, AKR) primary infections. Mice supporting acute or intermediate infections produced more intense antibody responses and total serum IgG1 concentrations were higher than in mice tolerating chronic infections. Positive correlations across mouse strains between the intensity of the antibody response and the percentage loss of worms in weeks 6 and 10 were established. No correlation was found between the response within mouse strains and loss of worms by individual mice. Heavy infections gave marginally higher antibody titres than low intensity infections, but few significant differences were detected and it was concluded that infection intensity did not markedly influence the magnitude of the antibody response. Male and female mice responded similarly despite the earlier loss of worms from females. No association was found between the primary response phenotype and recognition of particular antigens in Western blot analysis, nor did intensity of infection or host gender affect recognition. The possibility that immunomodulatory properties of adult worms may have had a differential influence on ability of strains of contrasting response phenotype to mount IgG1 responses was discussed.
Stage and isotype specific immune responses in a rat model of filariasis
Authors: LAWRENCE R. A. , DENHAM D. A.
Published: October 2007

Inbred PVG rats infected with 100 Brugia pahangi infective larvae (L3) divide into rats that develop microfilaraemic infection (Mf+), and those that remain microfilaria negative (Mf‐). All rats had high levels of specific IgG to adult worm and L3 extracts, however, after the onset of microfilaraemia, Mf+ rats had significantly higher levels of IgG to Mf extract. Mf+ rats recognized several antigenic components of each developmental extract that were not responded to by Mf‐ rats. In particular Mf+ rats recognized a triplet of proteins of 61‐67 kD in microfilarial extract from day 74 post infection onwards. This indicated that these proteins were stage specific to Mf and Mf‐ rats had not been exposed to Mf rather than Mf absence being due to a protective antibody response. Analysis of the immunoglobulin isotype usage during infection revealed that each isotype was independent both in its period of induction and the developmental stage to which it responded. The predominant isotypes responding throughout infection were IgG1, IgG2a and IgM. Specific IgG2b and IgG2c were elevated early in infection but after the onset of microfilaraemia antibody of these subclasses was suppressed. The antigenic profiles recognized on immunoblots by IgG1, IgG2a and IgM were very similar.
Type I hypersensitivity reactions in intestinal mucosae from rats infected with Fasciola hepatica
Authors: O'MALLEY K. E. , SLOAN T. , JOYCE P. , BAIRD A. W.
Published: October 2007

Type I hypersensitivity reactions in the intestinal tract of sensitized animals may contribute to resistance to reinfection with Fasciola hepatica. Colonic mucosae isolated from previously infected rats were voltage clamped in Ussing chambers. Antigen was prepared as a crude homogenate from adult liver fluke. Assay of serum antibodies against fluke antigen confirmed sensitization. Antigen challenge evoked a rapid onset, transient inward current in sensitized but not in control preparations. Chloride secretion accounted for at least part of the response since the loop diuretic bumetanide reduced the effect of antigen by 61%. Anti‐rat IgE mimicked the response to antigen and desensitized tissues to subsequent antigen challenge. Local synthesis of eicosanoids may mediate the response to antigen since the cyclo‐oxygenase inhibitor piroxicam reduced the response by 76%. In contrast, mepyramine which is a histamine receptor antagonist did not alter the ion transport response evoked by antigen. Tetrodotoxin reduced the response to antigen by 53% implicating intrinsic neurons within the lamina propria as effector cells in the responses of this tissue to antigen. We propose that antigen stimulation of electrogenic chloride movement and consequent fluid secretion in vivo may contribute to a local effector mechanism in prevention of reinfection of previously sensitized hosts.
Effect of macrophage infection by Leishmania on the proliferation of an antigen‐specific T‐cell line, TPB1, to a non‐parasite antigen
Authors: LYTTON SIMON D. , MOZES EDNA , JAFFE CHARLES L.
Published: October 2007

The ability of Leishmania mexicana amazonensis to inhibit antigen specific T‐cell proliferation against a non‐parasite polypeptide antigen, poly(LTyr, LGlu)‐poly(DLAla)–poly(LLys), was examined. Infection of mouse peritoneal macrophages by promastigotes blocked the proliferation of the T‐cell line, TPB1. This effect was correlated with the level of parasite infection, and the timing of macrophage infection and antigen addition. Peritoneal macrophages from both BALB/b and C57BL/6 mice showed reduced ability to serve as antigen presenting cells.
Immunosuppression in trypanotolerant N'Dama cattle following Trypanosoma congolense infection
Authors: FLYNN J. N. , SILEGHEM M.
Published: October 2007

Tsetse‐transmitted Trypanosoma congolense infection causes an impairment of in vitro T cell proliferative responses in Boran (Bos indicus) cattle. To assess the importance of this phenomenon as it may relate to the ability of trypanotolerant cattle to control infection with trypanosomes, T cell proliferative responses to mitogenic stimulus with Concanavalin A were measured in N'Dama (Bos taurus,) cattle throughout infection. The responses of peripheral blood mononuclear cells from Boran and N'Dama cattle were similar. Depressed proliferative responses were observed with cells of both breeds at 12 days post infection, after which the responses returned to levels similar to those recorded pre‐infection. Immunosuppression was also studied in the lymph nodes of a major histocompa‐tibility complex (MHC)‐matched pair of N'Dama cattle. Lymph node cells from the infected animal failed to respond to mitogenic stimulus. Co‐culture experiments in which the cells from this node were mixed with either lymph node cells or peripheral blood mononuclear cells from the non‐infected MHC‐compatible animal revealed the presence of suppressor cells, acting in a prostaglandin‐independent manner, capable of arresting mitogen‐induced T cell proliferation.
Granulomatous hypersensitivity to Schistosoma mansoni EGG antigens in human schistosomiasis. IV. A role for prostaglandin‐induced inhibition of in vitro granuloma formation
Authors: GOES ALFREDO M. , REZENDE SIMONE A. , GAZZINELLI GIOVANNI , DOUGHTY BARBARA L.
Published: October 2007

The prostaglandins (PG) are known to regulate immune cell function(s) and participate in the progression of both acute and chronic inflammatory reactions. Using an in vitro model of Schistosoma mansoni egg‐induced hypersensitivity granulomas, we have delineated the role of immune complexes (IC) in the induction and release of PG and their inhibitory effects on granuloma development. The hypersensitivity‐type granuloma reaction to soluble egg antigen (SEA) was examined using a model of in vitro granuloma formation. Our results show that granuloma formation was dramatically suppressed by the addition to the granuloma cultures of IC, PGE1, PGE2, while PGF2 alpha had no significant effect. The inhibition of the PG function was achieved by the introduction of anti‐PG antibodies that blocked suppression of granuloma formation. It appears in this model system that IC may inhibit the activity of granuloma formation by stimulating the monocyte‐macrophage lineage to release inhibitory mediators. Our results suggest that the prostaglandins E series may be important in the generation and maintenance of suppression of the granulomatous inflammatory response to S. mansoni egg antigens.
Inhibition of Plasmodium falciparum growth in vitro by CD4+ and CD8+ T cells from non‐exposed donors
Authors: H. FELL ANDREW , CURRIER JEFF , F. GOOD MICHAEL
Published: October 2007

T cells from most adult non‐exposed donors, which express a memory phenotype (CD45RO+), can respond by proliferation to P. falciparum asexual stages in vitro. Such cells may have arisen from exposure to environmental organisms. To address the efficacy of such cells in eliminating parasites and investigate the mechanisms involved, we have used an in vitro assay where parasite growth can be precisely monitored in the presence of different cell preparations. Unfractionated peripheral blood mononuclear cells (PBMC) from both malaria‐exposed and non‐exposed donors inhibited parasite growth by up to 62% in a two day assay. Purified T cells in the presence of adherent cells had a similar effect, but purified T cells alone or adherent cells alone had minimal effect. Antigens released at the time of schizont rupture were maximally effective in stimulating interferon‐γ (IFNγ) production. Neutralizing antibodies to IFNγ showed a partial reduction of growth inhibition in some individuals tested suggesting that different mechanisms may be operative. Neutralizing antibody to TNFα had a partial effect in combination with anti‐IFNγ. Antibodies to IL‐1 and IL‐4 had no effect. T cell fractionation experiments showed that while purified CD4+ T cells from some donors produced IFNγ and inhibited parasite growth, purified CD8+ T cells could inhibit parasite growth to a greater extent without production of detectable IFNγ. Four parasitised red blood cell clones (CD4+, TCRαβ+, IFNγ producing) derived from non‐exposed donors inhibited parasite growth to comparable levels, but one clone showed low production of IFNγ whilst the other three produced high levels. Our data show that T cells from non‐exposed donors have the potential to eliminate malaria parasites via non‐IFNγ dependent mechanisms. Such mechanisms may contribute to a degree of innate resistance to malaria in vivo, and may be able to be targeted by malaria vaccine programs.
Antigen presentation by epidermal langerhans cells in experimental cutaneous leishmaniasis
Authors: AXELROD OFRA , KLAUS SIDNEY , FRANKENBURG SHOSHANA
Published: October 2007

Cutaneous leishmaniasis is a disease induced by intradermal injection of leishmania promastigotes. Since the first cells the parasite encounters are those of the skin, the involvement of this organ in the early immune response might be relevant to the outcome of the disease. In this study we examined the ability of epidermal langerhans cells (LC) to become infected in vivo and to function as antigen presenting cells during the early hours of infection with Leishmania major. Our experiments showed that LC from mice injected with parasites can present antigen to a leishmania‐specific T cell line when LC are obtained as early as four h after infection. The stimulation was specific, since LC from leishmania injected mice did not present antigen to an ovalbumin‐specific T cell line nor did LC from ovalbumin‐injected mice present antigen to the leishmania specific T cell line. Despite the ability of epidermal LC cells to present antigen, no parasites were detected in the epidermis, suggesting that these cells are not directly involved in establishing an infection.
Identification of a 94‐kilodalton antigen on Leishmania promastigote forms and its specific recognition in human and canine visceral leishmaniasis
Authors: ROLLAND LAURENCE , ZILBERFARB VLADIMIR , FURTADO ANDRE , GENTILINI MARC
Published: October 2007

We have analysed by immunoblotting sera from humans and dogs with visceral leishmaniasis, from the Old World as well as the New. When lysates of promastigotes are used as antigens, antibodies against a 94 kDa Leishmania component are detected, regardless of the age and geographical origin of the patient, the serum antibody titre as measured by indirect immunofluorescence, and the number of arcs in counterimmunoelectrophoresis. Low dilutions of sera from patients with Old and New World cutaneous leishmaniasis did not react with the 94‐kDa antigen, whatever the species of Leishmania used as antigens. Sera from patients with other infections than leishmaniases, or without infection, are negative, even at low dilution. Anti‐94 kDa antibodies were detected in the sera of Leishmania‐infected dogs from both the Old and the New World. When lysates of Leishmania mexicana axenic amastigotes are used as antigens, the 94‐kDa antigen was little or none identified by sera from humans and dogs with visceral leishmaniasis, and never recognized by control sera. Thus, the specific recognition of the 94‐kDa promastigote antigen in human and canine visceral leishmaniasis suggests that this antigen could be a potential candidate in the differential immunodiagnosis of the disease.
Neospora caninumin dogs: detection of antibodies by ELISA using an iscom antigen
Authors: BJÖRKMAN C. , LUNDÉN A. , HOLMDAHL J. , BARBER J. , TREES A. J. , UGGLA A.
Published: October 2007

An indirect enzyme linked immunosorbent assay (ELISA) for detection of antibodies toNeospora caninumin serum from dogs is described. Extracted tachyzoite proteins incorporated into immunostimulating complexes (iscoms) were used as coating antigen. A mixture of a monoclonal antibody to dog immunoglobulin G and a horse radish peroxidase conjugated antibody to mouse Ig was used to detect bound antibody. When the iscom preparation was analysed by means of sodium dodecyl sulphate polyacrylamide gel electrophoresis it appeared to consist of a restricted number of proteins compared with whole parasite homogenates. In immunoblot analysis, usingN. caninumpositive sera from rabbits and dogs as probes, the major antigens recognized had approximate molecular weights between 30 and 45 and 17 to 19kDa. Compared with an ELISA using a crude solubilized tachyzoite antigen, the iscom ELISA substantially improved the sensitivity and specificity (to 97·6% and 95·6%, respectively, against an immunofluorescence test, IFAT, as indicator of true status). There was a statistically significant positive correlation between IFAT titres and iscom ELISA OD450values. The iscom ELISA absorbances (and the IFAT titres) of dogs with proven clinical infections were not higher than those from nonclinically affected, putatively infected dogs.
Vaccination against the cat flea Ctenocephalides felis felis
Authors: HEATH ANDREW W. , ARFSTEN ANN , YAMANAKA MILES , DRYDEN MICHAEL W. , DALE BEVERLY
Published: October 2007

Non‐chemical control of haematophagous parasites is a desirable goal. We report here on the use of concealed antigens from the major digestive organ of the cat‐flea as vaccine components. Rabbits were immunized with various antigens from cat flea midguts, and immunoglobulin from these rabbits was fed to cat fleas in an artifical feeding system. Antibody produced against soluble antigens from the midguts of fed fleas was able to kill fleas in this system. Dogs were then immunized with various antigen preparations, and challenged for a week with live fleas. Significantly fewer live fleas were recovered from dogs immunized with fed midgut supernatant, and recovered live female fleas produced significantly fewer eggs. This study indicates the possibility of vaccination as a means of control of flea, and possibly other blood sucking insect populations.
Immunosuppression by a neutral thiol protease from parasitic helminth larvae in mice
Authors: HAMAJIMA F. , YAMAMOTO M. , TSURU S. , YAMAKAMI K. , FUJINO T. , HAMAJIMA H. , KATSURA Y.
Published: October 2007

The composition and immunological suppression of a novel proteinaceous material, a neutral thiol protease (NTP), isolated from the metacercaria of the helminth Paragonimus westermani are reported. From cDNA cloning and sequencing, the protease was found to be composed of 215 amino acid residues and closely resembled the known cysteine proteases. Treatment of adult mice with the enzyme suppressed the delayed footpad reaction and haemagglutinin antibody production, and reduced expression of the major histocompatibility complex and interleukin 2 receptor on lymphocytes, and induced suppressor cells in the spleen. In addition, stable and long‐term skin graft survival was achieved by concomitant administration of the enzyme at a low dose.
Selective effector mechanisms for the expulsion of intestinal helminths
Authors: NAWA YUKIFUMI , ISHIKAWA NAOTO , TSUCHIYA KIMIYUKI , HORII YOICHIRO , ABE TATSUYA , KHAN AZHARUL I. , SHI BING , ITOH HIROSHI , IDE HISAMITSU , UCHIYAMA FUKUMI
Published: October 2007

In the middle of the era of molecular biology, much less attention is paid to in vivo phenomena. However, carefully designed experimental systems in vivo still can provide valuable information as to the mechanisms underlying the establishment and maintenance of host‐parasite relationships. In this review we describe the advantage of using concurrent infections with appropriately chosen combinations of different genera or different maturation stages of parasites to segregate the cellular responses of the host. By means of simple experimental approaches we have found that mucosal mast cells and goblet cells, both of which have long been considered as non‐specific effectors, are in fact highly selective and specific effector cells of the host defence mechanisms capable of acting on the establishment and the expulsion of intestinal helminths.