bluuebunny/crossref_metadata_2025_split huggingface dataset:
Killing of newly excysted juveniles of Fasciola hepatica in sensitized rats
Authors: DAVIES CAROLINE , GOOSE J. 
Published: October 2007

SUMMARYNewly excysted juvenile Fasciola hepatica were injected intraperitoneally into previously sensitized rats. They were recovered at various intervals post‐injection and examined by light and electron microscopy. The challenge flukes were rapidly coated with peritoneal cells which, in the early stages, were mainly eosinophils. The eosinophils adhered closely to the flukes and degranulated on to their surface releasing cytochemically detectable peroxidase. Vacuoles formed in the tegument of the flukes beneath the adherent eosinophils and these increased in size until they spanned the width of the tegument, thus destroying its continuity. From 4 h post‐injection some of the flukes had lost their teguments and were surrounded by phagocytic cells, particularly neutrophils; at this stage they were judged to be dead. During the first five minutes post‐injection degranulating mast cells were associated with the challenge flukes. Their role in eosinophil chemotaxis is discussed as are the possible mechanisms of eosinophil adherence and degranulation.Using an anti‐C3 fluorescein conjugate, it was demonstrated that C3 was not bound to the surface of challenge flukes either in vitro or in vitro in immune serum.
Immune responses of rats to live Vibrio cholerae: secretion of antibodies in bile
Authors: JACKSON G. D. F. , COOPER G. N. 
Published: October 2007

SUMMARYAgglutinating and vibriocidal antibodies appear in the bile of rats within a few days of intravenous or intraintestinal injection of live Vibrio cholerae. Whereas the presence of IgM and IgG antibodies are accounted for by passive exudation from serum, those of the IgA class are selectively (actively) transferred from serum to bile. Bile duct ligation causes a 10‐fold increase in serum IgA levels over a 48‐h period; a similar increase in agglutinating antibody titre occurs only in rats injected intraintestinally, thus providing further evidence for the predominance of IgA‐antibody formation when antigen is taken up from the intestinal lumen. Biliary antibodies do not appear to augment the antibody levels in mucus secretions that adhere to the small intestine surfaces. However, when the bile flow is interrupted by bile duct occlusion or cannulation, the antibody levels in these secretions increase in parenterally‐immunized animals. It is unlikely, therefore, that bile duct ligation will provide a satisfactory approach to determining the protective function of biliary V. cholerae antibody.
Immunization of ferrets against Diroflaria immitis by means of chemically abbreviated infections
Authors: BLAIR LYNDIA SLAYTON , CAMPBELL W. C. 
Published: October 2007

SUMMARYFerrets were exposed to two successive inoculations with 30 third‐stage larvae of the canine heartworm Dirofilaria immitis, the inoculations being approximately 5 months apart. Each infection was terminated by ivermectin therapy approximately 2 months after inoculation. The ferrets were challenged with 30 larvae 3 weeks after the termination of the second infection, and were necropsied approximately 6 months after challenge. Of the four ferrets that survived this protracted experimentation, two were entirely free of heartworm while the other two had only a single female worm each. In contrast, 14 control ferrets that had not been immunized (four of which had been given ivermectin doses) were all infected at necropsy, yielding a mean of 6.6 worms per ferret.
Stimulation of immunity to Nematospiroides dubius in mice using larvae attenuated by cobalt 60 irradiation
Authors: HAGAN P. , BEHNKE J.M. , A. PARISH HEATHER 
Published: October 2007

SUMMARYInfective larvae of Nematospiroides dubius attenuated by cobalt 60 irradiation are extremely effective at stimulating immunity. Previously, such levels of protection could only be obtained with multiple immunizations of normal larvae. The critical factor underlying this protective response appears to be the dose of irradiation given to the immunizing infection. Various doses of irradiation have been tested and the most effective of these range between 10 and 30 krad. The experiments show that provided this level of irradiation is used, the number of immunizing infections is relatively unimportant. Such use of irradiated larvae will be of value in attempting to analyse the immune mechanisms which operate against N. dubius. The possible mechanisms of immunity to N. dubius are discussed.
Immunity to Strongyloides ratti in rats. 1. Adoptive transfer with mesenteric lymph node cells
Authors: MOQBEL R. , WAKELIN D. 
Published: October 2007

SUMMARYAdoptive transfer of immunity against the enteral phase of Strongyloides ratti was monitored using four parameters; namely, number of worms recovered, position occupied in the host's small intestine, worm length and fecundity. When immune mesenteric lymph node cells (IMLNC) were transferred from donors infected for 20, 26 or 32 days into recipients infected for 3 days, a marked acceleration of worm expulsion was evident by day 16 post‐infection (p.i.). IMLNC from day‐16 p.i. donors did not transfer expulsion. In an experiment in which recipients were given 2 × 108 or 1 × 108 IMLNC from donors infected for 26 days, accelerated worm expulsion occurred only with the higher inoculum, although manifestations of direct worm immunity, i.e. altered position and reduced length and fecundity, were evident in both cases. Transfer of IMLNC appeared to have no effect upon worm establishment; when cells were transferred on the day of infection a period of 16 days was necessary to effect both direct anti‐worm immunity and expulsion, although the former was evident on day 14 p.i. However, when IMLNC were transferred to rats already infected for 6 days, a very significant reduction of their worm burden was apparent 10 days after IMLNC transfer.
The nature of immunity against Trypanosoma crtczi in mice recovered from acute infection
Authors: SCOTT M.T. 
Published: October 2007

SUMMARYProtective immunity against a lethal, Y strain, T. cruzi infection could be transferred to normal mice by either serum or spleen cells from mice which had recovered from the acute phase of infection. The ability of spleen cells to transfer immunity was abolished by B lymphocyte removal (anti‐Ig column fractiona‐tion), but was relatively insensitive to T lymphocyte depletion (anti‐Thy 1.2 plus complement) or macrophage removal (Sephadex G‐10 fractionation). Immune spleen cells gave an anamnestic antibody response when injected together with T. cruzi antigen into lethally irradiated recipients and these antibodies conferred protection in a passive transfer system. T cell depletion reduced, but did not abolish, this antibody response. These data imply that the protective immunity of T. cruzi‐convalescent mice is predominantly B cell‐mediated with T cell involvement being restricted to a helper role.
Suppressor T cells in the specific control of the carrier response to schistosomula in mice infected with Schistosoma mansoni
Authors: RAMALHO‐PINTO F.J. , SMITHERS S.R. 
Published: October 2007

SUMMARYThe carrier effect, using TNP‐labelled schistosomula was used to measure the helper T‐cell activity against the schistosomula surface in CBA mice exposed to 30 cercariae of Schistosoma mansoni. After infection the helper T‐cell activity reached a peak in 8–10 days, but by 6 weeks it had declined to background levels. Five × 107 spleen cells from chronically (12‐week) infected mice when injected into 9‐day infected mice caused a specific suppression of the helper T‐cell response to schistosomula. Subsequent fractionation of the spleen cell population using a nylon wool column and specific depletion of T cells from the spleen cell population with anti‐Thy 1·2 antisera and complement, showed that the suppressive activity was due to T cells. We conclude that during infection of mice with S. mansoni a population of suppressor T cells is generated which partially regulates antibody production against schistosome surface antigens.
Characterization of surface antigens of Trichinella spiralis infective larvae
Authors: Parkhouse R.M.E. , Philipp M. , Bridget  , Ogilvie M. 
Published: October 2007

SUMMARYInfective larvae of Trichinella spiralis were surface‐labelled with radioactive iodine, and the products were characterized biochemically and immunochemically. The labelled material was restricted to two basic subunits: a lentil lectin‐adherent glycoprotein (GP), mol. wt 47K, and a lentil lectin‐non‐adherent protein fraction (P), mol. wt 55K. Both of these form homologous dimers through as yet unspecified covalent bonds to yield GP90 and P105. The GP is further polymerized into higher molecular weight forms by disulphide bond‐dependent associations, suggesting a highly cross‐linked arrangement in the cuticle. To what extent this structure contributes to the overall organization of the cuticle remains to be established. The two labelled surface molecules are immunogenic in the infected host, and do not react with a panel of sera taken from animals chronically infected with other nematode species. The approach therefore offers immediate possibilities for immunodiagnosis in nematode infections, and for a comparative immunochemical study of the surface cuticle of different stages of the same and different nematode species and for studies of the function of the nematode cuticle.
Immune complex glomerulonephritis in experimental kala‐azar
Authors: SARTORI ALEXANDRINA , DE OLIVEIRA ALBANITA VIANA , ROQUE‐BARREIRA MARIA CRISTINA , ROSSI M. A. , CAMPOS‐NETO A. 
Published: October 2007

Summary In the present work we demonstrate that hamsters infected with L. donovani eliminate large quantities of immunoglobulins in the urine. This alteration is clearly a consequence of a conspicuous immune complex glomerulonephritis readily detectable 7 days after the beginning of infection. L. donovani antigens and hamsters immunoglobulins (Igs) were revealed as granular deposits in the mesangial areas and contiguous loops of the glomeruli.Histopathological alterations such as focal mesangial proliferation with progression to diffuse proliferation were observed in the first 3 weeks of infection. From day 35 onwards, all diseased animals presented large deposits of amyloid material of predominantly glomerular localization.In consonance with these alterations, Igs were detected in the urine by day 21 of infection and their concentration increased substantially with the progression of disease. In contrast, serum Igs increased until day 21, when their concentration dropped steadily.
Antibody isotypes in human schistosomiasis mansoni
Authors: JASSIM A. , HASSAN K. , CATTY D. 
Published: October 2007

Summary Summary Schistosoma mansoni‐infected subjects from the Gezira Irrigated Area of Sudan were studied for serum immunoglobulin levels, and specific antibody titres to larval, adult and egg stage antigens, by class and IgG subclass. The 276 subjects were adult chronic cases (frequently exposed male canal cleaners), primary school children, and hospital‐referred cases with acute symptoms including hepatosplenomegaly. Chronic untreated cases were compared with a similar group of canal cleaners 3 months after successful chemotherapy with Praziquantel administered at the start of the non‐transmission season. All cases, except those previously treated, were egg positive at the time of blood sampling. Data from infected and treated cases were compared with measurements of serum immunoglobulin in a panel of European blood donors. The major findings are as follows:There is a consistently elevated total serum IgG concentration in infected groups which is accounted for mainly by an increased IgG1 subclass (greatest in chronic cases) and by a remarkable 10‐to 11‐fold increase in IgG4 in the untreated chronically infected group and in the schoolchildren.All infected groups showed high IgG antibody responses to all life cycle stage antigens, and IgM titres were high to adult and egg antigens in untreated canal cleaners. Major differences were evident in the distribution of IgG subclass antibodies between the infected groups: the response to larval and adult antigens is poor or absent in IgG1, IgG2 and IgG3 in untreated chronic infections but is high in IgG4, whereas in acute cases with hepatosplenomegaly and in schoolchildren IgG1, IgG2 and IgG3 antibodies to larval antigens are in high titre but IgG4 and IgM responses to larvae are low or absent, the response in these isotypes being restricted in these cases to adult and egg antigens. Comparing the treated and untreated canal cleaners, although these are separate groups, the data suggest that Praziquantel reduces total serum IgA and IgM levels but has little effect on the raised IgG component except for the IgG4 subclass. The treated chronic cases show a reversal in the ratio of IgG1, IgG2 and IgG3 to IgG4 antibodies to larval and adult antigens compared with the untreated chronic group—the IgG4 response being low by 3 months after treatment and the IgG1, IgG2 and IgG3 being high. These data are discussed in relation to the possible importance of antibody isotype selection in determining host susceptibility to infection, with reference to age, exposure and treatment of the host.
The biotin‐streptavidin system in a two‐site ELISA for the detection of plasmodial sporozoite antigen in mosquitoes
Authors: VERHAVE J.P. , LEEUWENBERG A.D.E.M. , PONNUDURAI T. , MEUWISSEN J. H. E. Th. , VAN DRUTEN JAM. 
Published: October 2007

Summary A two‐site ELISA has been designed for the detection of sporozoite antigen in mosquitoes. Biotin‐labelled monoclonal antibodies against sporozoites and a streptavidin‐biotin‐peroxidase complex were used to visualize the antigen.Evaluation of the sensitivity and specificity of the procedure was carried out and background levels of reactivity on the basis of negative mosquitoes were calculated. The test has been deliberately kept as simple as possible for use in the tropics and was designed using Anopheles stephensi infected with in vitro cultivated Plasmodium falciparum gametocytes.A minimum of about 100‐350 sporozoites could be detected in mature salivary gland infections; in addition sporozoite antigen was detected in mosquitoes several days before the entry of sporozoites into the salivary glands. No reaction was demonstrable either with bloodstage or ookinete antigens of P. falciparum, or with mosquitoes carrying sporozoites of other plasmodial species. The number of sporozoites in positive mosquitoes and the generating capacity of a single oocyst could be assessed by the use of a calibration curve based on dilution data of a known sporozoite suspension. It was found that a single oocyst can produce about 10 000 sporozoite equivalents.
Specificity of Toxocara ELISA in tropical populations
Authors: LYNCH N.R. , WILKES L.K. , HODGEN A.N. , TURNER K.J. 
Published: October 2007

Summary The diagnosis of human infection by Toxocara canis relies heavily upon serological tests, the specificity of which can be inadequate in regions of endemic helminthiasis. When different population groups of tropical Venezuela were evaluated using ELISA based upon Toxocara excretory‐secretory antigen (TcES A), solid‐phase adsorption of the sera with extracts of a wide variety of non‐homologous parasites revealed the existence of significant cross‐reactivity. This was effectively and conveniently overcome when the test sera were incubated in the presence of the soluble parasite extracts in a competitive inhibition ELISA. The mean reduction of ELISA values caused by pre‐adsorption of the sera tested was 32‐2%, and that caused by competitive inhibition was 42‐3%, the effects of these two procedures being strongly correlated (r=0.83). The magnitude of the reduction was inversely proportional to the actual ELISA value (r=‐0.55), and ranged from a mean of 68.0% in sera from apparently healthy individuals of medium‐high socio‐economic level, down to 28.1% in heavily parasitized Amazon Indians. Ascaris showed the greatest degree of cross‐reactivity in these tests, although under conditions of competitive inhibition even sera with high levels of antibody against this parasite could be negative in Toxocara ELISA. Western blotting revealed a major 81 400 D component that was shared between Ascaris and TcESA.Our results indicate that the competitive inhibition of cross‐reactivity by soluble non‐homologous parasite extracts provides a convenient and economical means of increasing the specificity of ELISA for the determination of the seroprevalence of toxocariasis in tropical populations.
Mature liver stages of cloned Plasmodium falciparum share epitopes with proteins from sporozoites and asexual blood stages
Authors: SZARFMAN ANA , ALYON JEFFREY , WALLIKER DAVID , QUAKYI ISABELLA , HOWARD RUSSELL J. , SUN SUSAN , BALLOU W. RIPLEY , ESSER KLAUS , LONDON WILLIAM T. , WIRTZ ROBERT A. , CARTER RICHARD 
Published: October 2007

Summary The liver mcrozoites of malaria parasites arc of paramount importance, as they initiate the parasite invasion of red blood cells and start the cycle associated with the clinical features of malaria. Investigating liver merozoite antigen is difficult because of the lack of a rodent model of human malaria. In addition, only a low proportion of cells are obtained in vivo, the parasites from Cebus and Aotus monkeys are immature, and in‐vitro experiments with liver cells are often confounded by contamination with the natural mosquito flora co‐purified with the sporozoites used for seeding the liver cultures.In our study, mature liver schizonts were shown to possess many of the antigenic determinants recognized by MoAbs and sera specific for defined sporozoite and blood‐stage antigens. We employed an immunofluorescence procedure based on evaluating parasites in cryosections prepared from infected chimpanzee liver. Sufficient numbers of sectioned parasites were evaluated with each antibody to assure the reproducibility of the results, and the fixation procedure used was sufficiently non‐destructive to parasite antigens so that clear differences between reactions of specific antibodies and negative controls were observed.Our evidence for sharing of epitopes by liver merozoites and sporozoites or by liver merozoites and asexual blood‐stage parasites raises the possibility that immune responses elicited against sporozoites or asexual stage antigens being considered as vaccine candidates may also act against this important, little‐studied stage of the parasite.
Immunity to coccidiosis: genetic influences on lymphocyte and cytokine responses to infection with Eimeria vermiformis in inbred mice
Authors: WAKELIN D. , ROSE M. E. , HESKETH P. , ELSE K. J. , GRENCIS R. K. 
Published: October 2007

SUMMARYCellular and cytokine responses to infection with Eimeria vermiformis were compared in BALB/c (resistant) and C57BL/6 (B6‐susceptible) inbred mice. Cellular responses in the mesenteric lymph node (MLN) occurred sooner after primary infection in the resistant BALB/c strain. In contrast, proliferative responses occurred earlier after challenge in B6 mice. Resting levels of CD4 + ve and CD8 + ve T‐lymphocytes in the MLN differed between the two strains but the relative numbers of each subset remained relatively constant throughout primary infection. MLN cells taken at intervals after infection were assayed for release of the cytokines IFN‐gamma, IL‐5 and IL‐10 after culture in vitro with the mitogen Concanavalin A (Con‐A) or with parasite antigen. With either stimulus cells from resistant BALB/c mice released IFN‐gamma and IL‐5 earlier after infection than did B6 cells. The strains had a comparable absolute ability to produce IFN‐gamma but BALB/c cells released more IL‐5 than did B6, levels declining, rather than increasing, during primary infection in the latter. Only cells from BALB/c mice released IL‐10 during infection. Cells taken after a secondary infection released relatively little cytokine after pulsing in vitro. These data suggest that the difference in response phenotype between the two strains when infected with E. vermiformis reflect a kinetic, rather than a qualitative, difference in ability to mount protective T‐helper (Th) cell subset responses. No evidence was found for a Th2‐mediated interference with ability to release IFN‐gamma, the cytokine most closely associated with protective immunity.
The role of reactive nitrogen intermediates in modulation of gametocyte infectivity of rodent malaria parasites
Authors: MOTARD ANNIE , LANDAU IRENE , NUSSLER ANDREAS , GRAU GEORGES , BACCAM DOANH , MAZIER DOMINIQUE , TARGETT GEOFFREY A. T. 
Published: October 2007

SUMMARYDirect feeding of Anopheles stephensi mosquitoes on mice infected with Plasmodium vinckei petteri showed that, during the periods of schizogony in the blood, the infectivity of gametocytes was markedly reduced. This could be prevented by prior injection of the L‐arginine analogue, Nw‐nitro‐L‐arginine (NwNLA) showing that the altered infectivity was due to reactive nitrogen intermediates (RNI). Similar effects on transmission of P. yoelii nigeriensis were demonstrated in vitro by membrane feeding of the mosquitoes. The in vitro reduction in infectivity could be reversed by injecting the L‐arginine analogue either into the infected mouse donor of serum, or into the membrane feeding chamber. Elevated levels of TNF and IL‐6 were demonstrated during the course of infection but did not correlate well with nitrogen radical activity. Similarly, direct measurements of NO2‐ and NO3‐ did not reflect the nitrogen radical activity revealed by addition of the specific L‐arginine analogue.
Stage‐specific surface antigens of the cattle lungworm Dictyocaulus viviparus
Authors: BRITTON COLLETTE , CANTO GERMINAL J. , URQUHART GEORGEM. , KENNEDY MALCOLM W. 
Published: October 2007

SummaryImmunofluorescence on live Dictyocaulus viviparus parasites revealed a significant antibody response by vaccinated and patently infected bovine hosts to the sheath of infective larvae (L3), a structure which is generally thought to be shed from the parasite surface prior to invasion of host tissue. In contrast, surface‐exposed antigens of the adult, egg and pulmonary L1 stages were recognized only by serum antibody from calves exposed to a patent lungworm infection. Radioiodination of sheathed L3 identified a restricted set of components while a more complex pattern of labelled material was observed with adult parasites. Many more components of adult worms were labelled by the Bolton‐Hunter than by the lodogen reagent, probably reflecting the more penetrative labelling propensities of the former. Stage‐specificity of surface‐associated antigens of adult parasites was demonstrated by their immunoprecipitation by antibody from patently‐infected, but not from vaccinated, calves. There was no in vitro release of the major iodinatable surface‐associated antigens of adult parasites nor any binding of antibody raised against adult excretory‐secretory (ES) products to the surface of living adult worms, suggesting that surface components do not contribute to adult ES products in this species. Antibody responses to the surface of adults. L1 and eggs were specific to patently‐infected animals and may provide a useful indicator of exposure to patent infection.