摘要:

SummaryWe showed that infection withTrypanosoma congolensein mice led to suppression of listeria‐induced delayed type hypersensitivity (DTH). Mice were pre‐treated with irradiatedT. congolenseorT. eiansi, which caused rapid and effective suppression of DTH. A membrane fraction obtained by homogenizingT. eiansivariant in a hypotonic buffer solution and centrifuging it at 150,000g produced suppression of listeria‐induced DTH when injected i.p. into mice as early as 1 day before listeria immunization. Furthermore, we demonstrated by an adoptive transfer system that the suppressor cells involved in this suppression had developed in the spleen and that the activity of the splenic suppressor cells was due to the presence of a macrophage popul

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1985.tb00062.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryTetracosactrin, a synthetic adrenocorticotrophic hormone (ACTH) analogue delivered by osmotic minipumps implanted s.c. in mice induced a dose‐dependent increase of plasma corticosterone levels. In mice with an established immunity toPlasmodium bergheithe increase of the plasma corticosterone level due to tetracosactrin treatment correlated with loss of immunity against this malaria parasite. The observed plasma corticosterone levels associated with loss of malaria immunity were of the same order as those in mice that lost their immunity during pregnancy. Adrenalectomy before administration of the ACTH analogue prevented both the increase of plasma corticosterone and loss of malaria immunity. Adrenalectomized mice still lost their malaria immunity when treated with the synthetic corticoid dexamethasone. The effector function of malaria immunity is sensitive to corticoids, and. at least during pregnancy, the naturally occurring serum corticosterone level appears to be an important regulator of malaria immunit

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1985.tb00063.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryIn experiments designed to test why high levels of antibody‐dependent, eosinophil‐mediated killing of schistosomula are routinely observed in this laboratory, several factors that may contribute to variations in eosinophil activity were examined. The most important factors were: (1) the source of eosinophils, with marked variation being demonstrated not only, as previously shown, between individuals, but also between different cell preparations from a single individual; (2) the serum used as a source of anti‐schistosomulum antibodies and (3) the age of the schistosomula at the time of assay. In contrast, addition of fresh normal serum as a source of complement had a relatively slight effect when the killing assay was carried out in round bottomed tubes. A more marked enhancement was observed in flat bottomed microtitre plates, and it is suggested that this enhancement may be attributable to the release of chemotactic complement components. No difference was observed between a laboratory maintained and a recently derived isolate ofSchistosoma mansoni, either in initial susceptibility or in loss of susceptibility after 3·5 h of culture. In contrast to the marked effects of eosinophils under most conditions tested, there was no evidence for extensive neutrophil‐mediated damage under the same co

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1985.tb00064.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryThe production of antibodies against the schistosomulum surface antigens ofSchistosoma mansoniin response to immunization with highly irradiated cercariae was followed. Four antigens were reproducibly identified by125I surface labelling using lodogen and immunoprecipitation; they had mol. wts of 38, 32, 20 and 15 kD. In addition a 92 kD antigen was also evident in most experiments. It was demonstrated that the 20 kD antigen was the same as that recognized by the monoclonal antibody NIMP/M.47 and that this antigen like the 38 and 32 kD antigens was thus identified during both chronic infection and following vaccination with irradiated cercariae. Two weeks following immunization with irradiated cercariae antibody was produced only against the 15 kD antigen but at 4 weeks the major response was against the 32 kD antigen. A second immunization with irradiated cercariae boosts the antibody response so that all four antigens were strongly precipitated. Further vaccinations did not lead to the identification of further antigens. Immunization of rats with highly irradiated cercariae also resulted in antibody production against the 38, 32, 20 and 15 kD antigens. Surface labelling of schistosomula transformed from irradiated cercariae resulted in the same four antigens being precipitated as from normal cercariae indicating that irradiation did not affect transformation nor antigen expression on 3h schistosomula. Furthermore, antibodies againt the same surface antigens were detectable 4 weeks after immunization with equal numbers of cercariae irradiated with 0, 5, 25 or 50 krad. Vaccination of mice with irradiated, cloned cercariae resulted in identical antibody production and similar levels of immunity directed at both an homologous or heterogeneous challenge. Thus all parasites within our laboratory population appear to express the same antigens and there was no evidence for a genetically defined variation that could account for the

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1985.tb00065.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryComplement (C) activation induced byEntamoeba histolyticain normal non‐immune human serum was studied by testingin vitrothe ability of different fractions of the trophozoites to cause C3 breakdown. Whole trophozoites were found to activate both alternative and classical C pathways. The antibody‐independent classical pathway (MgEGTA inhibitable) C activating capacity was found to greatly increase after disruption of the cell membrane by sonication. Subsequent analysis after differential centrifugation and ion exchange chromatography of the membrane/particulate fractions showed, that this activity was not due to DNA, which has been shown to have the similar characteristics, but to other, as yet unidentified components. A rather homogenous membrane fraction obtained by elution with 0·4 M Tris‐HCl, pH 8·1 (described as 4M) and some cytoplasmic constituents obtained after gel chromatography retained a moderate degree of alternative pathway C3 activating capacity seen with intact trophozoites. Thus, it seems, that serum contact to the outer surface ofE. histolyticatrophozoites leads to C activation via both pathways with cell death as the result and to subsequent release of more efficiently classical pathway activating components. These phenomena probably have an important role in the inflammatory process in invasive amo

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1985.tb00066.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummarySerum antibody responses of mice exposed to Philippine isolates ofSchistosoma japonicumhave been analysed by immunoprecipitation of exogenously radiolabelled antigens extracted from adult worms. Attention was focused on labelled protein antigens differentially recognized by sera of mice that differ genetically in their resistance status. Mice of the inbred strain 129/J can show high level resistance to first or repeated infection withS. japonicum.Even after six percutaneous administrations of 25 cercariae, approximately 50% of 129/J mice remain healthy with no or very feu worms present in the portal system. Sera from 129/J mice exposed toS. japonicumconsistently and differentially recognise an antigen of adult worms of mol. wt. 26,000. This antigen, termed Sj26, is not immunoprecipitated fromS. mansoniadult worms by sera from resistant 129/J mice. Serum antibodies to Sj26 are present in at least some patients with a history of schistosomiasis japonica. Whether immune responses to SJ26 are involved directly in expression of resistance toS. japonicumremains to be determined. However, this antigen produced by cloned DNA in expression vectors, or isolated from adult worms, is an obvious candidate to be tested for vaccination efficacy in mice.

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1985.tb00067.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SummaryBovine neutrophils, eosinophils and macrophages mediatedin vitrocytotoxicity againstTrypanosoma theileriin the presence of purified IgM, IgGl and IgG2 from immune bovine serum. When the immunoglobulin fractions were assayed at similar concentrations, IgM was the most effective isotype mediating killing with all three effector cell types. Using the ELISA with monospecific antisera against the different bovine isotypes and subisotypes, IgM was shown to be contaminated by<1%. The addition of 0·08 M 2‐mercaptoethanol inhibited IgM‐mediated ADCC but not that of IgGl or IgG2, and the cytotoxicity occurred in the absence of complement. The presence of isotype and subisotype specific Fc receptors on the bovine effector cells was investigated using a totally homologous erythrocyte‐antibody (EA) resetting technique. FC receptors for bovine IgM, IgG1 and IgG2 were detected on bovine neutrophils. Very few FcM receptors were detected on either eosinophils or macrophages, but FcG2 receptors were detected on both cell types, and FcG1 receptors on macrophages. However, eosinophils showed very few FcG1 receptors. The failure to detect all types of Fc receptor on the three different effector cells is dis

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1985.tb00068.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY