bluuebunny/crossref_metadata_2025 huggingface dataset:
The antibody recognition profiles of humans naturally infected with Ascaris lumbricoides
Authors: HASWELL–ELKINS MELISSA R. , KENNEDY MALCOLM W. , MAIZELS RICK M. , ELKINS DAVID B. , ANDERSON ROY M.
Published: October 2007

Summary A semi–quantitative analysis of individual human antibody responses to larval Ascaris excretory and secretory (ES) antigens using radioimmunoprecipi–tation and SDS–PAGE is presented. A significant relationship was observed between the intensity of antibody–precipitated radiolabeled ES antigens and host age. The antibody response profile followed a similar age–related pattern to that of intensity of infection, with blood samples from 5–9–year–old children showing the strongest banding patterns and the heaviest infections. These findings support the hypothesis that the degree of exposure to infective stages of Ascaris is a major determinant of the convex age–intensity profile observed in the community. Considerable heterogeneity was observed in the antibody profiles of individuals, particularly in the recognition of a 14 kD molecule. Positive correlations were observed between the strength of banding at several mol. wts and the worm burdens of individuals. However, the sample size was too small to determine whether these relationships simply reflect age–related profiles or represent independent associations between antibody levels and worm burden. When the data were stratified by age, negative associations between the strength of recognition of some bands and the intensity of infection were suggested and require further study.
Genetic control of immune response to a purified Schistosoma mansoni antigen. II. Establishment and characterization of specific I–A and I–E restricted T–cell clones
Authors: MENDLOVIC F. , ARNON R. , TARRAB–HAZDAI R. , PURI J.
Published: October 2007

Summary T–cell lines and clones specific for a partially protective schistosome antigen (9B antigen) were established from mice immunized with such antigen. The H–2 congenic strains BIO.A which express both I–A and I–E class II gene products of the major histocompatibility complex (MHQ and B10.A(4R) which only express I–A molecules were used in these studies. The specific T–cell lines recognized the 9B antigen in the context of either A or E molecules, but both class II antigens were necessary for maximal stimulation of the T–cell lines in lymphocyte proliferation assays. T–cell clones were derived from these lines and their MHC restriction was investigated. Both I–A and I–E restricted clones could be isolated. All clones were specific for 9B antigen showing different degrees of cross–reactivity with a total schistosome extract (CA sonicate). A correlation between the fine specificity of the clones and the expression of class II antigens was demonstrated. Gones specific for 9B antigen, or which reacted to the same extent with 9B antigen and CA sonicate, were I–A restricted, whereas clones which proliferated more in the presence of CA sonicate were all I–E restricted. This suggests that I–E restricted clones recognize more cross–reactive epitopes than I–A restricted clones. These antigen–specific T–cell clones should provide a useful tool for examining the role of class II antigens in the modulation of protective immune response during Schistosoma mansoni infection.
Production and characterization of human monoclonal antibodies against Schistosoma mansoni
Authors: GOES ALFREDO M. , ROCHA ROBERTO S. , GAZZINELLI GIOVANNI , DOUGHTY BARBARA L.
Published: October 2007

Summary We have produced a panel of human monoclonal antibodies (MoAb) from patients infected with Schistosoma mansoni in order to analyse more carefully the human immune response to this helminth infection. This study describes the production, characterization and analysis of these MoAbs. Briefly, peripheral blood mononuclear cells from chronically infected patients were (1) isolated and stimulated with parasite antigens in vitro, (2) positively selected for B–cells on anti–Ig columns, and (3) then transformed with Epstein–Barr virus (EBV). Once EBV cell lines were established, they were selected for anti–5. mansoni antibodies using an ELISA, cloned, retested and then fused with the mouse–human heteromyeloma SHM–D33. In this study, we describe five MoAbs which have different antigenic specificities for life–cycle stages based on ELISA to soluble crude antigen preparations, membrane immunofluorescence on whole intact organisms, and immunofluorescent staining of cryostat frozen sections. The importance of these reagents with regard to the human immune response to S. mansoni is currently being evaluated.
Portal system peculiarities may contribute to resistance against schistosomes in 129/J mice
Authors: MITCHELL GRAHAM F.
Published: October 2007

Summary Using the technique of latex microsphere injection into a mesenteric vein, evidence has been obtained for a ‘leaky’ portal system in 129/J mice maintained in this institute (WEHI129/J) and also in CS7BL/6 mice. Thus, 20–/im beads injected into the portal venous system of BALB/c and (BALB/cx129/J)Fi mice are trapped efficiently in the liver whereas in many 129/J and CS7BL/6 mice the bulk of the injected beads is found in the lungs. Peculiarities in the hepatic portal system may thus contribute to resistance of WEHI 129/J mice (and to a lesser extent C57BL/6 mice) to infection with Schistosoma mansoni and S. japonicum. The possibility is raised by the data that increased access to, or residency times in, the lungs increases opportunities for expression of anti–schistosome immune responses and, in particular, the effects of recently described T–cell–initiated inflammatory responses in this organ. The variability within groups of WEHI 129/J and CS7BL/6 mice in susceptibility to schistosomes as well as hepatic trapping of injected microspheres suggests that an infection of unknown type, proposed by others, contributes to the several peculiarities that have been described in at least 129/J mice.
Tumour necrosis factor (TNF) as a mediator of macrophage helminthotoxic activity
Authors: JAMES STEPHANIE L. , GLAVEN JUDITH , GOLDENBERG STANLEY , MELTZER MONTE S. , PEARCE EDWARD
Published: October 2007

Summary Lymphokine‐activated macrophages are cytotoxic for larvae of the helminth parasite Schistosoma mansoni. That soluble secreted factors may mediate this cytotoxicity was suggested by the observation that culture supernatant fluids from stimulated macrophages also exhibited larvacidal activity. These fluids contain the monokine tumour necrosis factor (TNF). Several observations indicated that TNF is directly toxic to schistosome larvae. Cytotoxic sera taken from BCG‐ or S. mansoni‐immunized mice after endotoxin challenge killed schistosomula in vitro, and upon gel filtration the larvacidal factor(s) in the sera co‐eluted with the tumoricidal activity defined as TNF. Recombinant‐derived TNF exhibited direct toxicity to schistosomula at high concentrations, or at lower concentrations in the presence of IFNγ. The larvacidal activity of macrophage supernatant fluids was abrogated by addition of either anti‐TNF antisera or Zn+2, which has been shown to inhibit TNF‐induced damage of tumour cells. Anti‐TNF and Zn+2 likewise suppressed schistosomulum killing by lymphokine‐activated peritoneal macrophages or the IC‐21 macrophage line, indicating that TNF also plays a role in the effector mechanism of larval killing by whole cells.
Evidence for enhancement of IgGl subclass expression in mice polyvaccinated with radiation‐attenuated cercariae of Schistosoma mansoni and the role of this isotype in serum‐transferred immunity
Authors: DELGADO VICTOR , McLAREN DIANE J.
Published: October 2007

Summary Serum or immunoglobulin fractions of serum from CBA/Ca mice vaccinated three or four times with radiation‐attenuated cercariae of Schistosoma mansoni have been investigated for their capacity to confer protection upon naive mice. The data confirm that around 35% protection can be transferred with polyvaccine mouse serum administered in 0.5‐ml aliquots 1 h before challenge (intravenously) and 24 h post‐challenge (intraperitoneally). We show in addition, however, that polyvaccine serum is also protective when injected into the skin site of challenge as a single 0.05‐ml aliquot. In contrast, lymphocytes obtained from the donors of protective serum conferred only 13% protection upon recipient mice. The passive cutaneous anaphylaxis assay showed that IgGl is incremented by polyvaccination, while passive transfer experiments revealed that of the different isotypes fractionated from whole protective serum, only IgG 1 has the capacity to protect naive recipients against challenge. The resistance transferred by IgGl represents more than 60% of that obtained with whole serum and can be achieved using either the intravenous/intraperitoneal or the subcutaneous administration regimen. Recipients of serum given via the subcutaneous route exhibit cutaneous inflammatory focal reactions which comprise 20% eosinophils and 80%i mononuclear cells; these foci entrap challenge larvae. The importance of IgGl subclass expression to the success of serum‐transferred resistance is discussed.
Immunization and challenge of mice with insect‐derived metacyclic trypomastigotes of Trypanosoma cruzi
Authors: KIRCHHOFF L.V. , HOFT D.F.
Published: October 2007

Summary Infection with Trypanosoma cruzi was established in the reduviid vector, Dipetalogaster maximus, by repeated feedings on mice with high parasitaemias, and metacyclic trypomastigotes (IMT) were collected in insect urine after blood meals. The infectivity of IMT in mice was assessed by placing varying numbers of organisms, ranging from 5 to 5000, on to the conjunctivae or oral mucosa of anaesthetized animals. Half of the mice exposed to as few as 20 IMT by either route became parasitized, and the minimum inoculum size that resulted in all mice becoming infected was 640 IMT by the ocular route and 1250 IMT in the mice given parasites by mouth. Mice were immunized by tail vein infusion of irradiated IMT. Animals in the immunized group and in two control groups were then challenged by deposition of IMT on to the oral mucosa. Two of five immunized mice and nine of 10 comparison animals developed acute T. cruzi infection after challenge. These results indicate that IMT produced in this system are highly infective and that inocula containing 500–1000 IMT applied to the conjunctivae or oral mucosa constitute a gentle contaminative challenge. Moreover, our findings suggest that sterile protection against a contaminative challenge may be inducible by immunization with IMT, but experiments involving larger numbers of animals must be performed to resolve this question.
Serum and neutrophils alter the rate of excretory/secretory antigen release by Toxocara canis infective larvae in vitro
Authors: WILLIAMSON H.J.E. , ALLARDYCE R.A. , CLEMETT R.S. , HIDAJAT R.R.
Published: October 2007

Summary Infective larvae of Toxocara canis are well suited for studies of nematode antigen expression in vitro. Larvae were labelled with 3H‐glucosamine, an approach permitting dual analysis of antigen quantity and composition. Their excretory/secretory (E/S) glycoproteins were efficiently labelled and antigen identity confirmed by immunoprecipitation, SDS‐PAGE and fluorography. Compartmental analysis revealed that common components of Mr 100–120 kD were present in somatic, surface and soluble material. The application of biosynthetic labelling and compartmental analysis of parasite responses in vitro to antibody, complement and neutrophils was tested. Results indicated that test larvae in vitro respond by quantitative rather than qualitative changes in antigen production. Specifically, human serum was shown to raise, and neutrophils depress, the rate of antigen release. The implications of these findings for establishing an in‐vitro model for analysis of host/parasite reciprocal adaptive responses are discussed.
Acquired immunity to Ancylostoma ceylanicum in hamsters
Authors: GARSIDE P. , BEHNKE J.M. , ROSE R.A.
Published: October 2007

Summary A laboratory model of acquired immunity to human hookworm is described. Significant resistance to challenge infection with Ancylostoma ceylanicum was elicited in mature DSN hamsters. The serum and mucosal antibody responses were investigated in both quantitative and qualitative terms and changes associated with immunity were identified. Marked differences in numbers of mast and goblet cells in the small intestine were also recorded and related to the immune status of the host.
Leishmania major: inhibition of the chemiluminescent response of human polymorphonuclear leukocytes by promastigotes and their excreted factors
Authors: EL‐ON JOSEPH , ZVILLICH MENACHEM , SAROV ISRAEL
Published: October 2007

Summary The effect of various leishmanial preparations on the chemiluminescent response (CR) of human polymorphonuclear leukocytes (PMN) was studied. Almost no CR was observed with PMN stimulated with either Leishmania promastigotes or their excreted factors (EFs). Promastigotes added to PMN stimulated with phorbol myristate acetate (PMA), at a proportion of 20 to 1, respectively inhibited approximately 80–83% of the CR activity. Leishmanial promastigotes, whether live or dead, infective or non‐infective as well as whole parasite homogenates, soluble and insoluble fractions, all decreased the CR of the PMN (PMN‐CR). A similar effect was also observed with leishmanial EFs. The degree of inhibition was dose dependent and increasing the amount of EFs in the reaction mixture resulted in decrease of the PMN‐CR. More than 80% of the total activity of the PMN‐CR was inhibited by 500 μg EFs added at zero time to the reaction mixture. The inhibition of PMN‐CR obtained from a patient suffering from a chronic infection caused by L. major was not significantly different from that observed with PMN from normal donors. The present study suggests that the PMN‐CR is impaired by the Leishmania parasites and their EFs and thus may allow a greater survival of the parasites within these cells.
Schistosoma mansoni: localization of the 28 kDa secreted protease in cercaria
Authors: MARIKOVSKY M. , ARNON R. , FISHELSON Z.
Published: October 2007

Summary Monospecific rabbit antibodies were utilized to localize the 28 kDa serine protease which is released from transforming schistosomula of Schistosoma mansoni in cercariae and freshly transformed schistosomula. This protease exerts two postulated activities, degradation of connective tissue proteins thus promoting skin penetration and release of the cercarial glycocalyx leading to accelerated schistosomular transformation. Upon immunogold labelling of cercarial cryosections, the 28 kDa protease was found stored in both the preacetabular and postacetabular glands. This enzyme was also detected in the cercarial glycocalyx by immunogold and immunofluorescence labelling and by its proteolytic activity. Following transformation and shedding of the glycocalyx, the same 28 kDa protease was found on the surface membrane of transformed schistosomula which are resistant to immune damage. It is suggested that the 28 kDa membrane protease which cleaves in vitro the complement proteins C3, C3b and C9, may promote in vivo immunoresistance of S. mansoni.
The primary antibody response of malaria patients to Plasmodium falciparum sexual stage antigens which are potential transmission blocking vaccine candidates
Authors: ONG C.S.L. , ZHANG K.Y. , EIDA S.J. , GRAVES P.M. , DOW C. , LOOKER M. , ROGERS N.C. , CHIODINI P.L. , TARGETT G.A.T.
Published: October 2007

Summary Thirty serum samples collected from adult patients attending the Hospital for Tropical Diseases, London, with P. falciparum malaria, were studied. Sera were screened by indirect immunofluorescence for anti‐gametocyte antibodies. Twelve of the serum samples taken from 14 patients with primary infections were found to have both IgM and IgG antibodies to gametocyte antigens and total Ig titres comparable with those of patients who had had previous malaria attacks. Sera of individuals from hyperendemic areas have been found to immunoprecipitate the 230 and 48/45 kD gametocyte surface antigens which are known targets of transmission blocking antibodies. To investigate the epitope specificity of the serum samples from our adult patients, competitive ELISAs with 3 monoclonal antibodies (MAbs) that block transmission and recognize different epitopes on the 48/45 Kd antigen, were carried out. Specific antibodies for these epitopes were found in 60% of the sera while nearly a third were able to inhibit the binding of at least two MAbs.
Production of tumour necrosis factor during murine cutaneous leishmaniasis
Authors: MOLL HEIDRUN , BINÖDER KERSTIN , BOGDAN CHRISTIAN , SOLBACH WERNER , RÖLLINGHOFF MARTIN
Published: October 2007

Summary We have assessed the role of tumour necrosis factor‐α (TNF) during cutaneous leishmaniasis and demonstrated that significant levels of TNF were released by spleen cells from infected mice after in vitro restimulation with Leishmania major promastigotes. Spleen cells from both genetically resistant and genetically susceptible mice were equally capable of producing TNF. After challenge with bacterial endotoxin, TNF activity could also be demonstrated in the serum of L. major‐infected mice and the titres correlated with the course of cutaneous disease in susceptible and resistant mice. TNF did not exert a direct leishmanicidal effect in vitro. Furthermore, our study indicated that macrophages are the source of L. major‐induced TNF activity and that its elicitation is dependent on the presence of T cells. These findings suggest that TNF acts in concert with other cytokines produced during L. major infection and that its role depends on the composition of T cell subsets and cytokines present.
Further studies on variable resistance of 129/J and C57BL/6 mice to infection with Schistosoma japonicum and Schistosoma mansoni
Authors: MITCHELL GRAHAM F. , WRIGHT MARK D. , WOOD SUSAN M. , TIU WILFRED U.
Published: October 2007

Summary Two mouse strains maintained in this laboratory (WEHI) are variably resistant to infection with Schistosoma japonicum and S. mansoni in that worms cannot be found in the liver and portal system in a high proportion (WEHI 129/J mice) or low proportion (C57BL/6 mice) some weeks after exposure to cercariae. Resistance can be as high as 100% in WEHI 129/J mice and is usually around 20% in C57BL/6 mice. The proportion of resistant mice closely parallels the proportion of mice that demonstrate a shunting of microbeads, injected into a mesenteric vein, from liver to lungs. This applies to F1 x WEHI 129/J backcross mice in which the data suggest oligogenic genetic effects although no evidence for a participation of MHC‐linked genes in the phenomenon has emerged. 129/J mice derived from the Jackson Laboratory do not show a shunting of beads from the portal system to the lungs but their progeny bred at WEHI do. Germ‐free WEHI 129/J mice resemble conventionally‐maintained, SPF‐derived WEHI 129/J mice in their variable resistance to schistosome infection. No satisfactory explanation for hepato‐portal system peculiarities in WEHI 129/J and C57BL/6 mice can be advanced as yet and a possibility raised in this paper is a contribution from nutritional factors such as hypervitaminosis A superimposed on a genetic predisposition in these two related mouse strains.
Clonal repertoire analysis of murine B cells specific for repeat sequence antigens of Plasmodium falciparum
Authors: VENN ALISON J. , ANDERS ROBIN F. , PIKE BEVERLEY L. , SHORTMAN KEN
Published: October 2007

Summary Clonal analysis of the murine B‐cell repertoire has been used to investigate the possible role of tandem repeat sequence epitopes of Plasmodium falciparum in immune evasion. A limiting dilution culture system was used whereby murine spleen cells were stimulated with the B‐cell mitogen Iipopolysac‐charide (LPS) in the presence of 3T3 fibroblast filler cells. One in three B cells were shown to produce clones secreting immunoglobulin measurable by an ELISA. The frequency of antibody forming cell precursors (AFCp) specific for the 3′ repeat epitopes of the ring injected erythrocyte surface antigen (RESA) was estimated in non‐primed mice and found to be low. However, an accurate frequency determination was not possible using this method since the detection of the few positive cultures was found to depend on the presence of more than one AFCp or its products. Limiting dilution analysis was used to assess the frequency and repertoire of splenic AFCp at various times after immunization with a synthetic peptide of the RESA 3′ repeat epitope (8 times 4‐mer), presented in various ways. There was no marked increase in LPS‐responsive AFCp specific for this antigen at the level of either IgM or IgG secretion. This was in marked contrast to the antibody response in vivo, where moderate IgG antibody titres, normally indicative of a secondary response, were seen in the serum of the same mice used for AFCp assay. This discrepancy between serum titre and AFCp frequency following immunization was not apparent with a non‐malarial antigen, keyhole limpet haemocyanin (KLH). It was concluded that the LPS‐stimulated limiting dilution culture system was not registering RESA‐specific memory AFCp. These results raise the possibility that the malarial antigens are deficient in memory B‐cell generation, or that secondary responses to these determinants may arise from a distinct B‐cell progenitor which is non‐responsive to LPS in vitro.
Cellular phenotypes in Trypanosoma congolense infected sheep: The local skin reaction
Authors: MWANGI D.M. , HOPKINS J. , LUCKINS A. G.
Published: October 2007

Summary Mononuclear cell subpopulations in local skin reactions (chancres) in sheep infected with metacyclic forms of Trypanosoma congolense were studied by indirect immunoperoxidase staining using a panel of monoclonal antibodies (MoAbs) specific for ovine leucocyte subsets. Morphometric analysis revealed significant increases in numbers of cells expressing CD5, CD4, CD8, CD45R (mainly B cells), major histocompatibility complex (MHC) class II antigens, Fc receptors (FcR) on macrophages (VPM32) and FcR on B cells and macrophages (VPM33) from five days post‐infection. B cells which also expressed MHC class II were found mainly in dense aggregates. The CD4/CD8 ratios were raised over pre‐infection levels at 5–7 days post‐infection. In sheep which had been infected, treated with trypanocidal drugs and then challenged with an heterologous serodeme of T congolense, changes in cellular phenotype kinetics were similar to those seen in the skin in primary infections. Sheep superinfected with either an homologous or an heterologous, T. congolense serodeme showed only mild cellular infiltration and slight increases in various cellular phenotypes at the sites of inoculation.
Trichuris muris: antigen recognition and transfer of immunity in mice by IgA monoclonal antibodies
Authors: ROACH T.I.A. , ELSE K.J. , WAKELIN D. , MCLAREN D.J. , GRENCIS R.K.
Published: October 2007

Summary Mesenteric node lymphocytes from mice that had been infected with the nematode Trichuris muris, and then boosted with adult worm excretory‐secretory antigens were fused with myeloma cells to produce a panel of 9 monoclonal antibodies (MoAbs). Five of the MoAbs were of the IgA isotype. The antigen recognition profiles of these MoAbs were studied using SDS‐PAGE and immunoblotting: three major profile patterns were identified. Five MoAbs recognized a major band in the MW range 43‐48 kD; all recognized a range of antigens. Three MoAbs were used to localize antigens in the bodies of adult worms. Granules within the anterior stichocytes were recognized strongly, as was material within the eggs and pseudocoelom. Two MoAbs stained the cuticle. Although the phosphorylcholine (PC) determinant was widely distributed within worm tissues none of the MoAbs tested recognized PC. Passive transfer of immunity was achieved using two of the IgA monoclonals; no immunity was transferred by the Ig M and Ig G MoAbs used. The limited recognition profiles of these IgA MoAbs. and the ability to slain stichocyte granules, suggest that their protective activity results from an interaction with ES antigens.
Eosinophil‐larval‐interaction in onchocerciasis: heterogeneity of in vitro adherence of eosinophils to infective third and fourth stage larvae and microfilariae of Onchocerca volvulus
Authors: BRATTIG N.W. , TISCHENDORF F.W. , STROTE G. , MEDINA‐DE LA GARZA C.E.
Published: October 2007

Summary Adherence of eosinophilic granulocytes from patients with onchocerciasis to microfilariae (Mf), third (L3) and fourth (L4) stage larvae of Onchocerca volvulus was studied in vitro. Native and heat‐inactivated sera from patients with onchocerciasis (OS), from endemic controls without signs of the disease (ECS), from healthy Caucasians (NS) or foetal calf serum (FCS) served as sources for adherence mediating factors. In FCS‐supplemented medium eosinophils did not adhere to any larvae. None of the sera mediated the adherence of eosinophils to L4. Eosinophils adhered to L3 in the presence of OS, ECS and NS, whereas OS exclusively mediated adherence to Mf. Reduced adherence rates of eosinophils to L3 occurred in heat‐inactivated or zymosan‐activated OS, ECS or CS. Eosinophils bound to the L3 cuticle of moulting stage but not lo the newly exposed L4 cuticle. A single adherent layer of effector cells was found around cast L3 cuticle, multiple layers were found around intact L3 leading to subsequent paralysis of the larvae and to an amplification of the toxic effector potential by homotypic intereosinophilic adhesion. Our experiments document heterogeneity of in vitro effector cell adherence to the three larval stages of O. volvulus and indicate that complement‐dependent as well as independent mechanisms arc operative in eosinophil‐larval‐interaction. The results emphasize the importance of the invading infective larval stages of O. volvulus as possible targets for vaccine production.
Characterization of a polymorphic immunodominant molecule in sporozoites and schizonts of Theileria parva
Authors: TOYE P.G. , GODDEERIS B.M. , IAMS K. , MUSOKE A.J. , MORRISON W.I.
Published: October 2007

Summary This study examines several aspects of a polymorphic, immunodominant molecule (P!M) found in the protozoan parasite. Theileria parva. The antigen is present in all T. p. parva stocks examined, and in the related subspecies, T. p. bovis and T. p. lawrencei. It is the predominant antigen recognized by antisera from immune cattle on Western blot analysis of schizont‐infected lymphocytes, and is the only antigen which has been shown to react with anti‐schizont monoclonal antibodies (MoAbs) on Western blots or in immunoprecipitations. The antigen shows polymorphism in both size and expression of antibody epitopes among the different stocks of T. parva. The antigen is present in sporozoites as well as schizonts.
Interferon‐gamma‐mediated effects upon immunity to coccidial infections in the mouse
Authors: ROSE M. ELAINE , WAKELIN D. , HESKETH PATRICIA
Published: October 2007

Summary The effect of treatment with a monoclonal antibody (MoAb) capable of neutralising interferon‐gamma (IFN‐y) on the course of coccidial infections in mice (C57BL/6 and NIH infected with Eimeria vermiformis or E. pragensis, and BALBc infected with E. pragensis) was examined. The results differed with the species of parasite, the strain of mouse, the measure of infection and whether the infection was a primary or secondary one. The replication of E. vermiformis in primary infections was enhanced in bothC57BL 6 and NIH mice, but less MoAb was required in NIH than in C57BL/6 to produce similar effects. In neither strain did treatment prevent priming or interfere with the complete immunity to challenge normally induced by moderate infection with E. vermiformis. The replication of E. pragensis in primary infections was not affected in any of the strains of mouse but the clinical effects were exacerbated. Priming with E. pragensis was unaffected by treatment but the partial immunity to challenge, normally induced by infection with this species, was reduced when MoAb was given 2 h before challenge. This reduction was evident as an increased faecal output of oocysts and loss of body weight. These results confirm the role of! FN‐y in resistance to coccidiosis and further emphasise the complexity of the immune response in this disease.
Immunoprecipitation studies with biotinylated Entamoeba histolytica antigens
Authors: ANDREWS B.J. , BJORVATN B.
Published: October 2007

Summary The biotimlation of protein antigens for use in immunoprecipitation studies with parasite antigens is described. This technique was standardized to produec maximal labelling without compromising cither the viability of the parasite or the antigenicity of labelled proteins. Live axenic Entamoeba histolytica trophozoites were optimally labelled by incubation of 107 parasites in 1 ml phosphate‐buffered saline for 20 min at 37°C with a final concentration of 10 mM N‐hydroxy succinimido‐biotin (NHS‐B). Examination of antigens recognized by immunoglobulin from convalescent amoebic liver abscess patients and precipitated by protein A‐Sepharose showed a general increase in immune response to amoebic antigens with time following treatment. Mass ratio mol. wts of immunoprecipitated antigens concur with those presented by other authors using alternate technology, in addition to recognizing antigens previously not identified by human sera. We therefore recommend biotinylation as a viable alternative to radiolabelling techniques for the study of parasite antigens and the humoral immune responses raised against them.
Fine specificities of monoclonal antibodies against the Plasmodium falciparum circumsporozoite protein: recognition of both repetitive and non‐repetitive regions
Authors: BURKOT THOMAS R. , DA ZHOU WEN , GEYSEN H.MARIO , WIRTZ ROBERT A. , SAUL ALLAN
Published: October 2007

Summary The fine specificities of 6 monoclonal antibodies (MoAbs) raised against the circumsporozoite (CS) protein of the human malaria parasite. Plasmodium falciparum, were defined by their binding to a series of overlapping octapeptides corresponding to the 7G8 variant of the CS protein. The precise specificities of the MoAbs to the immunodominant NANP repeat region were elucidated by their binding lo all possible 4, 5, 6, 7 and 8 amino acid peptides in this region. All 6 MoAbs recognized the NANP repeats. In addition all MoAh bound to nonrcpctitive sites with 4 of the 6 MoAbs recognizing known functional sites outside the repeat region including sites required for T cell recognition and hepatocyte invasion. Antibody pressure may therefore be responsible for generating the epitope variation observed at T cell sites. The multiple specificities for all the MoAbs suggests that the repeat region may act as an internal immunological ‘smokescreen’ by competing more effectively for antibody binding compared to single epitope copy functional sites located outside the repeat region.
Necator americanus secretory acetylcholinesterase and its purification from excretory‐secretory products by affinity chromatography
Authors: PRITCHARD D.I. , LEGGETT K.V. , ROGAN M.T. , McKEAN P.G. , BROWN ALAN
Published: October 2007

Summary Acetylcholinesterase (AChE) secretion by adult N. americanus was enhanced in vitro by incorporating insoluble collagen rafts into culture dishes. Enzyme produced in this way had preferential substrate specificity for acetylthio‐choline iodide (ATC), and its activity was inhibited by cscrine (1.1 × 10−8m). Ancylostoma ceytanicum, another hookworm species, failed to produce comparable amounts of AChE in culture. AChE was efficiently purified from culture medium by affinity chromatography on edrophonium sepharose; 81% of the AChE activity was retained by the affinity matrix, although this fraction contained only 4.3% of the protein loaded. Antisera raised against purified AChE in rabbits immunohistochemically stained the oesophagcal glands of the parasite, and reacted with molecules of 32, 60, 80, 140 and 220 kDa in reduced adult ES products on Western blotting, although differential activity was observed against worm homogenatcs and earlier developmental stages. On IEF, purified AChE resolved predominately with a pl of 3.55; proteins with a similar pi were recognized by rabbit anti‐AChE. IgG preparations of this anliserum inhibited AChE activity in ES products, and inhibited AChE secretion by adult worms in culture. The availability of this immunological probe will allow definitive experiments to be conducted on the role of this enigmatic enzyme in the host‐parasite relationship.
Protective studies in sheep immunized with cuticular collagen proteins and peptides of Haemonchus contortus
Authors: BOISVENUE R.J. , STIFF M.I. , TONKINSON L.V. , COX G.N.
Published: October 2007

Summary Twenty‐eight nonsibling sheep aged approximately 12 months and raised in a helminth‐free environment were used in two protection studies. Immunizations were conducted by two intramuscular injections 30 days apart with a synthetic 18AA cuticle collagen peptide and native cuticle collagens derived from the third‐ and fourth‐stage larvae of Haemonchus contortus. Ten days following the last immunization, the sheep were each given 500 infective H. contortus larvae per day for five consecutive days by intraruminal injection. Both collagen materials induced antibodies reactive with cuticle collagens; however, neither induced reproducible protection to H. contortus infections in vaccinated/ infected sheep. In the most extensive test, there were no statisical differences in mean faecal worm egg count for 56 days post worm challenge, in mean numbers of H. contortus and female fecundity ratios at necropsy of immunized and unimmunized sheep. Failure to reproducibly immunize sheep with cuticle collagens may be due to the inability of antibodies or host immune cells to reach the collagen epitopes in the nematode cuticle without prior surface coat removal as postulated in human nemaiode studies.
Longitudinal study of seroreactivities to Pf 155/RESA and its repetitive sequences in small children from a holoendemic area of Liberia
Authors: BJÖRKMAN A. , LEBBAD M. , PERLMANN H. , FREEMAN T. , HOGH B. , PETERSEN E. , GILLE E. , LINDGREN A. , WILLCOX M. , HANSON A.P. , PERLMANN P.
Published: October 2007

Summary Summary The seroreactivities to Pf 155/RESA antigen and to three oligopeptides (EENV)2, EENVEHDA and K(DDEHVEEPTVA)2, which constitute repeal subunits of the RESA molecule, were investigated between 1980 and 1986 in two cohorts of children (n= 114) with and without monthly chemosuppression (pulsed reduction of parasite load) against malaria from six months to five years of age during development of protective immunity. Serum samples were collected first at half‐yearly and then yearly intervals. Positive immunofluorescence against Pf 155/ RESA (EMIF) was only found in 24% of the samples. The children with chemosuppression were more often seropositive (30%) than the non prophylactic children (17%). This was in contrast to the seroreactivity against crude parasitic antigens which was highest in the non prophylactic children. In these children, there was a general decrease of EMIF litres around two years of age. Immunosuppression by chronic parasitaemia may be suggested as a reason for this. ELISA seroreactivity was found against one, two or three oligopeptides in all children with high EMIF titres (>250) although (EENV)2 appeared to best correlate (92%) with the EMIF seropositivity. While EMIF seropositivity only showed partial correlation to immunoprotection against patent parasitaemia in the non prophylactic children, the individual profiles of the seroreactivities to the different specific epitopes of the Pf 155/RESA molecule and their relevance with regards to protective immunity to malaria need to be investigated further.
Production of interferons by bovine and ovine cell lines infected with Theileria annulata or Theileria parva
Authors: ENTRICAN G. , McINNES C.J. , LOGAN M. , PRESTON P.M. , MARTINOD S. , BROWN C.G.D.
Published: October 2007

Summary Three bovine cell lines and four ovine cell lines infected with Theileria parva or Theileria annulata were examined for the production ofinierferon (IFN). Biologically active IFN was detected in the tissue culture supernaiants of four of the cell lines. Only one, a bovine cell line infected with T. parva, produced IFN‐y as measured by specific neutralization with a monoclonal antibody to bovine IFN‐y. This observation was confirmed by analysing RNA from the cell lines on Northern blots using an IFN‐y cDNA probe. The other three cell lines which produced IFN were infected with T. annulata. The IFN produced by those lines was not IFN‐y.
Detection of antibodies against glycolipids of Echinococcus multilocularis metacestodes in sera of patients with alveolar hydatid disease
Authors: PERSAT F. , VINCENT C. , MOJON M. , PETAVY A.F.
Published: October 2007

Summary Glycosphingolipids extracted from Echinococcus mutlilocularis meta‐cestodes were tested against sera from patients with alveolar hydatid disease (AHD). The tests were performed first by ELISA then by immunostaining on thin layer chromatography. A binding between the parasite glycolipids and antibodies of AHD human sera was observed by ELISA. The glycolipids related to this binding were specifically parasite neutral glycosphingolipids. No reaction was observed with parasite acid glycolipids nor with neutral glycolipid extracts from human or mongolian gcrbil erythrocytes. Comparison between absorbance values of 25 AHD sera and 20 control sera showed significant differences. Similar rosuhs were obtained with sera from hydalid cyst patients. Sera from patients with other parasitoses (schislosomiasis, strongyloidosis or paludism) were also tested. The reactive fractions were identified by immunosiaining on thin layer chromatography with AHD sera, they were neutral glycosphingolipids containing at least two carbohydrate residues. These results were compared with chromatograms obtained with hydatid cyst human sera and discussed.
Identification of phosphorylcholine containing antigens of Fasciola hepatica—successful tolerization against this epitope in experimental animals
Authors: SLOAN T. , DOOGE D. , JOYCE P.
Published: October 2007

Summary Phosphorylcholine containing antigens have been identified in the parasite Fasciola hepatica by immunoblotting and ELISA. Immunoblots probed with polyclonal and monoclonal antibodies indicate that the majority of antigens identified in both the immature and mature parasite contain both phosphorylcholine and non‐phosphorylcholine epitopes. One antigen of 58 kDa appears to contain predominantly PC epitopes or at least this epitope is the major one responded to by host animals. Successful immunoiolerization against the epitope PC was achieved by injecting the PC conjugate, ovalbumin PC, into neonatal rats. Immurunolerization against PC resulted in a 25% reduction in worm burden upon subsequent infection with Fasciola hepatica.
The effect of immune serum and complement on the in vitro phagocytosis of Babesia rodhaini
Authors: PARRODI FERNANDO , JACOBSON RICHARD H. , WRIGHT IAN G. , FITZGERALD CLARE J. , DOBSON COLIN
Published: October 2007

Summary The effect of immune serum and complement on the in vitro phagocytosis of Babesia rodhaini was investigated. Infected erythrocytes and parasites released from erythrocytes by lysis were phagocylosed by mouse peritoneal macrophages in vitro when the infected erythrocytes or parasites were exposed to hyperimmune B. rodhaini serum. Complement, in the presence of immune serum, did not reproducibly enhance phagocytosis of infected erythrocytes or parasites alone. When adjusted for its effect on normal erythrocytes and normal serum, complement generally inhibited rather than enhanced phagocytosis. When coupled with other published data, our data suggest that the activation of the immune system in vivo against this species of Babesia involves a series of mechanisms of which phagocytosis is but one.
Genetic control of the immune response to a synthetic vaccine against Plasmodium falciparum
Authors: PATARROYO MANUEL E. , VINASCO JAVIER , AMADOR ROBERTO , ESPEJO FABIOLA , SILVA YOLANDA , MORENO ALBERTO , ROJAS MAURICIO , MORA ANA LUCIA , SALCEDO MARGARITA , VALERO VICTORIA , GOLDBERG ANA KARLA , KALIL JORGE
Published: October 2007

Summary Two independent vaccination trials using a hybrid synthetic poly pep‐tide containing epitopes from four proteins of Plasmodium falciparum were performed. In the first trial 63 and in the second 122 volunteers were vaccinated, using different immunization schedules. The analysis of the humoral response to the vaccine, measured by IgG antibody titres to the polypeptide showed a bimodal distribution in both cases suggesting genetic control of the immune response to this protein. There was a small group of low or non‐responders and a large group of good responders. HLA phenotyping of the two groups disclosed an association of the low responders to HLA‐DR4 antigens with chi‐square P value of 0.00039 when compared with the good responders group. These findings provide evidence for the genetic control of the immune response to the synthetic vaccine by the association of this response with particular alleles of the HLA class II antigens; such findings may lead to an explanation of the mechanism involved in disease susceptibility and need to be used in the design of a totally effective vaccine.
Inability of Plasmodium vinckei‐immune spleen cells to transfer protection to recipient mice exposed to vaccine‘vectors’or heterologous species of plasmodium
Authors: WINKEL K.D. , GOOD M.F.
Published: October 2007

Summary Mice can be immunized to Piasmodium vinckei by repealed infections followed by cure. Such immunity is dependent on CD4 T cells and an architecturally modified spleen, but has little requirement for antibody. Thus, athymic mice can be exposed to P. vinckei and cured, but do not develop immunity. They are resistant to challenge with parasites, however, if they a re then given spleen cells from euthymic immunized animals. Such immune spleen cells, however, cannot transfer resistance to normal mice which have been exposed to BCG, Salmonella typhimurium, or vaccinia virus, and are only partially effective in transferring resistance to mice which have been previously immunized with heterologous plasmodia, P. yoelii. P. chabaudi and P. berghei. Mice exposed to varying numbers of irradiated P. vinckei‐pRBC do not develop immunity and nor are such animals protected following adoptive transfer of immune spleen cells. Cellular immunity to malaria may not only be dependent on a population of immune CD4 T cells, but may require a specifically architecturally modified spleen which may not occur following cither exposure lo candidate vaccine vectors, heterologous plasmodia or non‐viable homologous plasmodia.
An experimental model for canine visceral leishmaniasis
Authors: ABRANCHES PEDRO , SANTOS‐GOMES GABRIELA , RACHAMIM NURIT , CAMPINO LENEA , SCHNUR LIONEL F. , JAFFE CHARLES L.
Published: October 2007

Summary Seven mixed‐breed dogs were challenged with either promastigotes or amastigotes of Leishmania donovani infantum strains recently isolated from naturally infected dogs. Different routes and numbers of parasites were utilized and each dog was monitored for at least 1 year post‐infection. Anti‐parasite specific antibody levels were measured by enzyme‐linked immunosorbence, immunofluorescence, crossed‐immune electrophoresis and Western blotting on crude antigen. Western blotting on two pure parasite proteins, dp72 and gp70‐2. was also done. Mitogenic and antigen‐specific stimulation of peripheral blood lymphocytes was monitored; and the haematological, clinical and parasitological parameters measured. Dogs challenged with amastigotes exhibited a more pronounced humoral response to leishmanial antigens. Only in one case was strong antigen‐specific proliferation detected. Clinical signs of disease, including hypergammaglobulinaemia, enlarged lymph nodes and the presence of parasites, were also more apparent in the dogs challenged with amastigotes. None of the seven dogs died. Serum antibodies to leishmanial antigens were apparent between 15 to 3 months following challenge and correlated with the appearance of enlarged lymph nodes, hypergammaglobulinaemia and the presence of parasites in tissue biopsies. Serum antibodies remained chronically high in these dogs throughout the period of the study. Only one dog (1/3) challenged intravenously with promastigotes and the dog challenged intradermally with amastigotes produced transient antibody responses to leishmanial antigen.
Non‐specific resistance of sheep against Haemonchus conforms with Freund's complete adjuvant
Authors: BAUTISTA‐GARFIAS C.R. , FLORES‐HERNANDEZ O. , QUIROZ‐ROMERO H.
Published: October 2007

Summary Six groups of four ovines each were injected intraperitoneally with Freund's complete adjuvant (FCA), at various limes before, during, or after infection with 10000 larvae (L3) of Haemanchus contortus per sheep. Animals in groups A and B received FCA on days 14 and 7, respectively, before infection. Ovines in group C were treated with FCA on the same day of infection; while sheep in groups D, E. and F were injected with the adjuvant on days 7. 14. and 21, respectively, after infection. Significant reductions in adult worm numbers compared with non‐treated controls, as determined 42 days after infection, were of 30%, 34%, 45%. 52%, 56%, and 55% in groups A, B, C, D, E, and F, respectively. A significant correlation, between the time of FCA administration (referred to the day of infection) and the number of worms recovered at necropsy, was also observed.
Free radical generation and the course of primary infection with Nippostvongylus brasiliensis in congenitally athymic (nude) rats
Authors: SMITH N.C. , OVINGTON K.S. , BRYANT C.
Published: October 2007

Summary The course of primary infections with Nippastrongylus brasiliensis was followed in nude (CBH/R nu/nu) and heterozygote(CBH/R nu/+) rats. In both nude and heterozygote rats peak egg production by N. brasiliensis occurred on days 7 and 8 post‐infection. However, whereas in heterozygote rats egg production declined rapidly thereafter and ceased completely by day 14 post‐infection, in nude rats high numbers of N. brasiliensis eggs were still seen on day 27 post‐infection, when the experiment was terminated, in comparison with the nude rats, heterozygote rats had a 5‐fold greater loss of weight by day 9 post‐infection and a 4‐fold higher incidence of diarrhoea. Furthermore, infected heterozygote rats became anaemic whereas uninfected rats and infected nude rats showed no evidence of anaemia. Free radical generation was measured in infected (9 days) and uninfected rats. Leucocytes from infected heterozygote rats were able to generate copious quantities of free radicals in response to N. brasiliensis whereas leucocytes from infected nude rats produced only slightly more free radicals than uninfected rats. Thus, worm rejection, weight loss, diarrhoea, anaemia and free radical generation in response to N. brasiliensis infection arc all T‐cell dependent events.
Vaccination with‘concealed’antigens: myth or reality?
Authors: WILLADSEN P. , McKENNA R.V.
Published: October 2007

Summary Cattle infested with the tick Boophitus microplus produce antibodies lo intrinsic membrane glycoproteins of the lick, as well as to Bm86. a well characterized antigen from the tick gut. Several factors explain how cattle could produce antibody to such antigens, which one would expect to be ‐concealed from the host's immune system, during natural infestation. Il has been shown that the carbohydrate determinants on many tick glycoproteins are cross‐reactive immunologically and that the reaction of bovine antibodies with intrinsic membrane glycoprotein is at least partially blocked by low molecular weight carbohydrate. Further, antisera from cattle exposed to licks read with a glycosylated, native Bm86 but not with a non‐glycosylated, recombinant Bm86. Thus the reaction of concealed antigens with antibodies produced as a result of lick infestation appears to be due lo a relatively non‐specific reaction with carbohydrate determinants on tick glycoprotein. Evidence is also presented that antibodies directed against carbohydrate determinants of Bm86 arc not protective. Care must therefore be exercised in interpreting the results of antibody reaction with glycoproteins in such complex organisms.