bluuebunny/crossref_metadata_2025_split huggingface dataset:
Antigen expression during development of the human hookworm, Necator americanus (Nematoda)
Authors: CARR A. , PRITCHARD D. I. 
Published: October 2007

Summary Summary The accumulated and de novo synthesized antigens expressed by L3, L4 and adult Necator americanus. recognized by both the natural host, man, and the experimental host, the hamster, were identified by immunoblotting and immunoprecipitation analysis. Following infection of neonatal hamsters serum samples were taken on days 17, 35 and 117. Only serum taken 117 days after infection showed significant reactivity in immunoblotting experiments, recognizing adult epitopes of 30000, 33000, 48000 and 69000 mol. wt thereby suggesting that few accumulated antigens are shared between developmental stages. By contrast, immunoprecipitation analysis of metabolically labelled proteins suggested that L3 and in particular L4 larvae synthesize some antigens which comigrate with those synthesized and accumulated by adult worms. In addition, L4 larvae synthesize a 41000 mol. wt excretory/secretory (ES) stage specific antigen.Parallel experiments using serum samples from infected humans, demonstrated that hamsters and man recognize many antigens of identical molecular weight. Notable in this respect are accumulated adult antigens of 30000, 33000, 48000 and 69000 and de novo synthesized antigens of 30000, 33000, 44000, 46000 and 69000 mol. wt. Some individual human sera mainly recognized L3 antigens of 47000–69000 mol. wt in immunoblotting experiments whilst others simultaneously recognized adult epitopes. This differential recognition of developmental stages by individual human sera suggests that genetic or epidemiological factors are operative and warrants further study.Overall, these studies confirm the pronounced immunogenicity of Necator americanus in both man and an animal model and pave the way for analysis of the relevance of these antigens to field situations.
Associations between clinical disease, circulating antibodies and C1q‐binding immune complexes in human onchocerciasis
Authors: SISLEY B. M. , MACKENZIE C. D. , STEWARD M. W. , WILLIAMS J. F. , O'DAY J. , LUTY A. J. F. , BRAGA M. , EL H. , SHEIKH H. 
Published: October 2007

Summary Onchocerciasis is a disease where often there are high levels of serum antibodies and high parasitic loads. The role of immune complexes in the development of the disease is investigated here by studying non‐specific and Onchocerca volvulus specific immune complex levels, as well as the antibody concentrations, in the sera of 372 people living in either Southern (199) or Northern (173) Sudan; sera from Sudanese individuals (31) and Caucasians (21) living outside the onchocerciasis endemic area were also tested.The levels of non‐specific immune complexes (NS‐IC) in these sera were measured by a solid phase radio‐immunoassay and those of O. volvulus‐specific immune complexes (OV‐IC) by an assay measuring antibody‐excess complexes using Clq‐coated plates. The concentrations of O. volvulus IgG antibodies were measured by ELISA. Immune complex and antibody levels of the serum donors were compared with regard to their clinical status due to onchocerciasis. These clinical changes were classified according to onchocercal lesions related to either (a) the active destruction of microfilariae (acute changes), or (b) the long term tissue alterations (chronic changes). Data was analysed using the Odds Ratio method.A negative association between microfilarial load and immune complex level was found, with the higher levels of OV‐IC present in patients with the lower levels of dermal microfilariae (i.e., less than 10 mf/mg). Significant associations between immune complex levels and the severity of onchocercal disease were also found. Levels of OV‐IC specific immune complexes were higher in infected individuals carrying dermal onchocercal lesions than in those without such clinical changes; there was no apparent relationship between these levels and the
Antibody isotypes of immune complexes in schistosomiasis mansoni in Sudan
Authors: JASSIM A. , CATTY D. , HASSAN K. 
Published: October 2007

Summary From a panel of monoclonal antibodies to Schistosoma mansoni, one that is specific to a shared cercarial and schistosomular antigen, and does not react with other major parasite species including Fasciola hepatica, was selected for use as an antigen‐capture layer in a sandwich ELISA for detection of specific circulating immune complexes in the blood of S. mansoni‐infected subjects from Sudan. The test, which identifies immune complexes of only a single antibody‐bound antigen, is developed using human Ig class‐ and IgG subclass‐specific enzyme (HRP)‐antibody conjugates. European blood donor sera and those with rheumatoid factor and/or anti‐nuclear antibody are negative in this test. The prevalence and distribution of the different antibody isotypes in antigen‐specific complexes was determined in 276 subjects of four infection groups; primary school children, adult irrigation canal cleaners with chronic infections, an equivalent group of Praziquantel cured canal cleaners, and hospital‐referred cases with severe hepatosplenic symptoms. The isotype profiles of antibodies in the specific complexes were compared with those in the total serum complexes prepared by polyethylene glycol precipitation.In chronic infections and in children there is a high prevalence of IgG and IgM specific complexes, the IgG being predominantly IgG1, with little or no IgG3 and IgG4. Treated chronic infections show reduced specific complexes in all classes of antibody. Compared with chronic and children's infections, a large proportion of the patients with severe infections have in addition to high IgM, high levels of IgG2, IgG3 and IgG4 specific complexes, a fact which suggests a causal relationship between antibody production in one or more of these subclasses to the circulating antigen and symptoms of hepatosplenic disease.Although all subjects have significant amounts of total serum complexes with IgG, untreated chronic infections have much higher concentrations than other infected groups. This group also has the highest levels and prevalence of IgM and IgE complexes. In treated chronic cases IgG and IgM total complexes are greatly reduced. The significant finding in patients with severe symptoms is the relatively high IgA immune complex level compared with other groups.Taken overall the results suggest that screening of populations in endemic regions for serum immune complexes by specific and non‐specific means could offer valuable data on the significance of antibody responses to circulating antigens in different isotypes in relation to pathogenesis. In addition the loss of complexes after chemotherapy may be of special value in determining the success of treatment regimens.
Immune dependence of schistosomicidal chemotherapy: an ultrastructural study of Schistosoma mansoni adult worms exposed to praziquantel and immune serum in vivo
Authors: MODHA J. , LAMBERTUCCI J.R. , DOENHOFF M.J. , McLAREN DIANE J. 
Published: October 2007

Summary This study examines the immune‐dependence of praziquantel (PZQ) for the treatment of Schistosomiasis mansoni in mice. We have shown elsewhere from worm recovery data that the efficacy of PZQ is significantly enhanced when mice are treated concomitantly with antisera raised against antigens released from adult schistosomes, even though such antisera show no intrinsic helminthotoxic activity (Doenhoff et al. 1987, DoenhofT, Modha & Lambertucci 1988). Moreover, indirect immunofluorescence assays have shown that male worms exposed to the dual treatment regime in vivo bind antiserum to their dorsal surfaces in a pattern that seems to follow the outline of the dorsal tubercles. Scanning and transmission electron microscopy have now been used to further define the features of damage inflicted upon worms through exposure to antiserum alone, drug alone, or the two treatments in combination. Such investigations revealed that the antiserum induces a classical membrane repair process in worms of both sexes, but little other damage. PZQ causes the formation of spherical protuberances on the dorsal tubercles of male worms, while the dual treatment regime induces both kinds of damage in male schistosomes, but with much enhanced severity. The protuberances show evidence of explosion and some regions of the tegument become completely destroyed.Regions other than the dorsal surfaces of the male worms do not exhibit comparable trauma, and neither do the females. These data are discussed in relation to the known schistosomicidal activity of PZQ, the notion that male and female worms exhibit regional and sexual differences in susceptibility, documerited evasive strategies of the parasite and the interdependence of immuno‐ and chemotherapy.
Analysis of peripheral leucocyte populations in N'Dama and Boran cattle following a rechallenge infection with Trypanosoma congolense
Authors: WILLIAMS D.J.L. , NAESSENS J. , SCOTT J.R. , McODIMBA F.A. 
Published: October 2007

Summary Monoclonal antibodies, flow cytometry and routine hacmatological techniques were used to analyse circulating leucocyte populations in trypanotoler‐ant (N'Dama) and trypanosusceptible (Boran) cattle following a homologous rechallenge with Trypanosoma congolense clone 1L13‐E3. The N'Damas developed a low, transient parasitaemia and did not develop anaemia. The Borans became parasitaemic and developed chronic anaemia but three of the five animals eventually self‐cured, whilst, a group of primary‐challenged Borans experienced a severe infection characterized by high levels of parasilacmia and acute anaemia.During infection the numbers of circulating B‐cells increased in all three groups from day 21 onwards. The proportion of B‐cells expressing the CD5 antigen increased from pre‐infection levels of 5‐10% of B‐cells to 49‐90% by day 19 post infection in all three groups. The neutrophil count declined in both Boran groups but not in the N'Damas. The CD4+ T‐cell and γδ T‐cell populations decreased in both Boran groups but did not alter significantly in the N'Damas. Although it was not possible to infer from the data, that the CD4+, γδ T‐cell, neutrophil and erythrocyte populations were directly responsible for the differential control of the disease by the two breeds, it was possible to correlate alterations in these cell populations with the severity of the disease.
In vitro lymphoproliferative responses to malaria antigens: a prospective study of residents of a holoendemic area with perennial malaria transmission
Authors: MSHANA R. N. , BOULANDI J. , MAYOMBO J. , MENDOME G. 
Published: October 2007

SUMMARYA longitudinal, prospective study to examine the relationship between the outcome of infection with Plasmodium falciparum parasites and in vitro T‐cell proliferative responses to a P. falciparum schizont extract (PfSE) was conducted in a village in south‐eastern Gabon, an area where malaria is holoendemic and transmission is intense and perennial. The donor's age was found to have a strong independent influence on all malariometric indices. At the community level, the in vitro lymphoproliferative response to PfSE was bimodal with 30% of the villagers studied showing persistently low responses. The frequency of low or high responders within the study population did not show any consistent relationship with the community parasite rates or the number of either patent parasitaemic episodes or clinical malarial attacks per individual. At the individual donor level, the response was negatively correlated with P. falciparum parasite density in those donors who were parasitaemic at the time of sampling. High in vitro lymphoproliferative responses to PfSE were predictive of resistance to clinical malaria. The PfSE‐induced in vitro lymphoproliferative response was dependent on antigen presenting cells, CD4+ T‐cells and UCHL‐1+cells.
The in vivo role of stem cell factor (c‐kit ligand) on mastocytosis and host protective immunity to the intestinal nematode Trichinella spiralis in mice
Authors: GRENCIS R. K. , ELSE K. J. , HUNTLEY J. F. , NISHIKAWA S. I. 
Published: October 2007

SUMMARYThe role of stem cell factor (SCF) in the generation of intestinal mast cell hyperplasia and host protective immunity following helminth infection was investigated using the Trichinella spiralis/mouse model. In vivo administration of a monoclonal antibody specific for the receptor for SCF (c‐kit) was found to completely prevent the generation of intestinal mastocytosis normally observed following T. spiralis infection. This was reflected by markedly reduced intestinal mast cell protease (IMCP) levels in both tissue and serum. Moreover, animals treated with anti‐c‐kit antibody failed to show any evidence of worm expulsion from the gut. The data demonstrate for the first time, a critical role for the SCF in the generation of mucosal mastocytosis and host protective immunity following an intestinal helminth infection.
Schistosoma mansoni: genetic non‐response to p40, the major protein antigen of the egg, reveals a novel mechanism enhancing IgM production during infection
Authors: TRZYNA WENDY C. , CORDINGLEY JOHN S. 
Published: October 2007

Summaryp40 is the major protein antigen in eggs and miracidia of Schistosoma mansoni. Immunization with recombinant p40 produced in bacteria and with p40 from miracidia reveals a conventional immune response gene effect in which H‐2b mice fail to produce antibody against p40. This is true when either denatured recombinant p40 and non‐denatured miracidial p40 are used as immunogens. In contrast, during infection all strains of mice produce antibodies to p40. However, non‐responder H‐2b mice produce only IgM to p40 and never any IgG. Thus, H‐2b mice appear to be producing specific IgM to p40 in the absence of MHC‐restricted T‐cell help. The mechanism revealed in these non‐responder mice might play an important role in stimulating the production of IgM ‘blocking’ antibodies to antigens from schistosomula which cross‐react with egg antigens.
Trypanosoma cruzi upregulates nitric oxide release by IFN‐γ‐preactivated macrophages, limiting cell infection independently of the respiratory burst
Authors: METZ GAËTANE , CARLIER YVES , VRAY BERNARD 
Published: October 2007

SummaryThe relationship between nitric oxide (N = O) produced by mouse peritoneal macrophages (MPM) and Trypanosoma cruzi infection is still poorly understood. The conditions of MPM activation by gamma‐interferon (IFN‐γ) to trigger a N = O‐dependent trypanocidal activity, as well as the effect of parasite infection or of reactive oxygen species (ROS) inhibitors on the N = O release were studied. T. cruzi infection occurring after a previous 24 h MPM activation induced an enhancement of nitrite levels (the stable degradation product of N = O) in cell supernatants; both the percentage of infected MPM and the number of amastigotes per infected cell were decreased in comparison to infected but non‐activated MPM. Addition of superoxide dismutase or catalase to non‐infected but activated MPM increased the nitrite levels; these were not detectable when L‐arginine inhibitors were added together with ROS inhibitors. The latter had no effect on infection nor on nitrite levels when infection occurred after pre‐activation, and induced only a weak nitrite release when infection took place before MPM activation. Altogether, these results support the involvement of N = O in the inhibition of T. cruzi infection by IFN‐γ‐preactivated macrophages, together with the upregulation of N = O release by T. cruzi infection independently of the respiratory burst.
The 35/50 kDa surface antigen of Trypanosoma cruzi metacyclic trypomastigotes, an adhesion molecule involved in host cell invasion
Authors: RUIZ RITA DE CASSIA , RIGONI VERA LUCIA , GONZALEZ JORGE , YOSHIDA NOBUKO 
Published: October 2007

SummaryWe have previously shown that monoclonal antibodies directed to the 90 kDa glycoprotein and the 35/50 kDa glycoconjugate, present on the surface of Trypansoma cruzi metacyclic trypomastigotes, inhibited host cell invasion. Here we investigated whether these molecules could be the ligands for the target cell receptor. Binding assays were performed by incubating Vero cells with sonicated parasite extract. Detection of bound parasite components was carried out by using monoclonal antibodies (MoAbs) 1G7 and 10D8, which recognize the 90 kDa and the 35/50 kDa antigens respectively. These experiments revealed that the 35/50 kDa glycoconjugate of metacyclic forms, but not the 1G7‐reactive antigen, binds to Vero cells. The purified 35/50 kDa antigen bound to Vero cells and inhibited the entry of metacyclic forms in a dose‐dependent manner. Although to a lesser extent, an immunologically related 35/50 kDa antigen of non‐infective epimastigotes also bound to Vero cells but it was unable to inhibit parasite penetration at a concentration (100 μg/ml) in which metacyclic antigen exhibited more than 60% inhibition. All these data suggest that the metacyclic 35/50 kDa surface glycoconjugate is a ligand to the host cell in the process ofT. cruzi invasion.
Identifying polymorphic regions of the p190 protein from different Plasmodium falciparum strains by using specific T cells
Authors: SÜSS G. , MATILE H. , MELOEN R. H. , TAKACS B. , PINK J. R. L. 
Published: October 2007

SummaryThe p190 protein (also called MSA1 or MSP1) of the asexual blood stage forms of Plasmodium falciparum, a human malaria vaccine candidate, shows polymorphism between different isolates. Mice were immunized with p190–3, a recombinant protein which contains mostly conserved sequences derived from the p190 protein of the K1 parasite isolate. Proliferative T‐cell responses of lymph node cells from immunized mice were assessed by stimulation in vitro with p190–3 or preparations of parasitized red blood cells (PRBC) containing the native protein. The p190–3‐specific T cells from C57BL/6 mice consistently responded to some P. falciparum isolates, representing either the K1 or MAD20 serotype of p190, but not to other P. falciparum strains or to rodent malaria parasite‐infected red blood cells. p190–3‐specific T‐cell responses from other mouse strains (BALB/c, C3H/He) did not distinguish between P. falciparum isolates. The polymorphic epitopes which were preferentially recognized by T cells from C57BL/6 mice were identified.
The analysis of the humoral response of the BALB/c mouse immunized with radiation attenuated third stage larvae of Brugia pahangi
Authors: BANCROFT ALLISON , DEVANEY EILEEN 
Published: October 2007

SummaryBALB/c mice immunized with L3 of Brugia pahangi, irradiated at 45kRad from a 137Caesium source, are strongly immune to challenge infection (75–100% reduction in the recovery of challenge infection larvae on day 6 post‐challenge). The target of immunity appears to be the post‐infective L3, as challenge infection larvae are killed within 5–6 days of infection. By immunoblot analysis, serum from immune animals recognizes a limited set of somatic antigens, the majority of which are shared between different life cycle stages. Serum from immune mice also strongly recognizes larval surface antigens by immunofluorescence, some of which may be stage specific. The larval surface determinants do not appear to be protein or glycoprotein by standard immunochemical analysis. A proportion of the antibody response of the BALB/c mouse is directed towards phosphorylcholine epitopes on filarial antigens, but the limited antigen recognition cannot be explained on the basis of the mouse strain used, as CBA/Ca mice recognize a similar limited set of antigens.
Characterization of excretory‐secretory products of adult Dictyocaulus viviparus and the antibody response to them in infection and vaccination
Authors: BRITTON COLLETTE , CANTO GERMINAL J. , URQUHART GEORGE M. , KENNEDY MALCOLM W. 
Published: October 2007

SummaryIn vitro released products of the adult stage of the bovine lungworm, Dictyocaulus viviparus, were characterized according to their SDS‐PAGE profile, glycosylation pattern, in vitro synthesis and antigenicity in the context of infection and vaccination with irradiated larvae. Biosynthetic labelling experiments with 35S‐methionine indicated active synthesis of ES throughout this time. There was, however, little incorporation of 3H‐glucosamine into ES products, and lectin affinity chromatography and glycopeptidase F digestion identified only one glycosylated component. Immunoprecipitation of 125l‐labelled ES products with sera from calves patently infected with D. viviparus demonstrated that all of these, with the exception of two components, are antigenic to the bovine host. One of those not immunoprecipitated was shown to be host serum albumin carried over into culture. A limited degree of cross‐reactivity between nematode species was observed, with a D. viviparus female‐specific antigen of 290 kDa being recognized by serum antibody from calves infected with the gastrointestinal nematodes Cooperia oncophora and Ostertagia ostertagi. Calves vaccinated with irradiated larvae of D. viviparus, despite not being exposed to the adult stage of the parasite, also showed some recognition of adult ES products. This might suggest that vaccination with irradiated larvae operates against both pre‐pulmonary and pulmonary stages of the infection.
‘Original antigenic sin’, T cell memory, and malaria sporozoite immunity: an hypothesis for immune evasion
Authors: GOOD MICHAEL F. , ZEVERING YINKA , CURRIER JEFF , BILSBOROUGH JANINE 
Published: October 2007

SummaryPrior to any exposure to malaria, most adults have T cells specific for malaria parasites and various malaria proteins. The protein for which this has been shown more than any other is the circumsporozoite protein (CSP) of Plasmo‐dium falciparum. These T cells can be present in high frequency and appear to have arisen through exposure to other (non‐malaria) organisms. Although T cells are thought to provide protection against sporozoites, these T cells specific for cross‐reactive organisms are clearly unable to protect against malaria, and may be preferentially expanded following exposure to malaria sporozoites. Thus, cross‐reactive organisms have the potential to skew the repertoire of sporozoite‐induced T cells and affect the induction of protective immunity. This is analogous to the concept of ‘original antigenic sin’ whereby prior exposure to one strain of influenza virus was shown to be able to divert the antibody response to a second challenging strain to focus on the shared (cross‐reactive) epitopes.
Synthesis of tumour necrosis factor‐alpha and interferons by mononuclear cells from Theileria annulata‐infected cattle
Authors: PRESTON PATRICIA M. , BROWN C. G. D. , ENTRICAN G. , RICHARDSON WENDY , BOID R. 
Published: October 2007

SummaryBovine macrophage‐derived tumour necrosis factor‐alpha/ cachectin (TNF‐α) was synthesized when peripheral blood mononuclear cells (PBMC) and purified adherent PBMC from naïve and Theileria annulata‐infected cattle were incubated in vitro with concanavalin A (Con‐A) or bovine recombinant interferon gamma (Bo rIFN‐γ). TNF‐α production was also induced when adherent PBMC were cultured with T. annulata macroschizont‐infected cells. In contrast, non‐adherent PBMC from sublethally infected cattle produced interferon (IFN) when incubated with Hu rIL‐2, Con‐A, phytohaemagglutinin (PHA) or T. annulata macroschizont‐infected cells growing as cell lines in vitro. Whilst PBMC from lethally infected cattle spontaneously produced IFN‐γ during advanced stages of infection, the sera of such animals contained type 1 IFN (alpha/beta). IFN was also produced by T. annulata macroschizont‐infected cell lines maintained in vitro. This work suggests that cytokines serve as crucial links between proliferating Theileira‐infected cells and the characteristic clinical symptoms of tropical theileriosis.