摘要:

SummaryT–cell lines generated fromTheileria parva–immunccattle were used to identify antigens associated with schizont–infected lymphoblastoid cells. Homo–genates prepared fromT.parua–infected cells were fractionated by differential centrifugation, and antigenically distinct soluble and membrane–bound antigens were detected by the differential stimulation of cell lines derived from two animals. Activity in the soluble fraction was not attributable to either a mitogen or interleukin 2. Activity in the membrane fraction was associated with schizont membranes as indicated by the presence in this fraction of a parasite protein detected by immunoblot analysis using a schizont–specific monoclonal antibody. Elimination of intracellular schizonts over time, using the anti–theilerial drug, parvaquone, resulted in a concomitant loss of antigenicity in infected cells and in subcellular fractions prepared from drug–treated cells, demonstrating that stimulation ofTheileria–sptahchelper and cytotoxic T–cell responses is associated with the pre

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00921.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryFreshly isolated human peripheral blood monocytes inhibited the growth of blood–stage asexualPlasmodium falciparumparasitesin vitro.The monocytes contained intracellular parasite pigment and a few whole parasites, but the remaining parasites reinvaded fresh red cells successfully and were morphologically normal. Anti–parasitic activity of these macrophages was not significantly enhanced by treatment with recombinant tumour necrosis factor α, recombinant γ–interferon or lymphoblastoid a–interferon. Catalase had no effect on this parasite inhibition, suggesting a hydrogen peroxide independent mechanism. Anti–parasitic activity was, however, enhanced by prior maturation of the monocytes. Monocytes matured for 6 days caused 100% killing of parasites. In contrast to identical concentrations of freshly isolated monocytes the parasites incubated with these matured macrophages showed intraerythrocytic death similar to the crisis forms seenin vivo, γ–interferon present either during the assay or as a pretreatment had no significant enhancing effect on the killing, although cytotoxicity to tumour cell lines was enhanced. Conditioned medium from macrophages showed only moderate paras

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00922.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryMonoclonal antibodies directed against the 51 kD merozoite surface antigen ofPlasmodium falciparumalso bind to other antigens within the infected cell. The sizes of these cross–reacting antigens have been characterized. Immunofluorescence due to the reaction of one of the monoclonal antibodies with these cross–reacting antigens was localized in the intra–erythrocytic parasite and in granules in the infected red cell cytoplasm. This immunofluorescence could be distinguished from the merozoite surface antigen in parasite lines with a variant serotype of the merozoite surface antigen which fails to react with the monoclonal antibodies. It was found that the in–vitro growth inhibition caused by the presence of one of the monoclonal antibodies, 8G10/48, was dependent on the expression of the corresponding serotype of merozoite surface antigen, a finding consistent with the inhibitory effect of this antibody being primarily directed against the merozoite surface antigen and not the cross–reacting antigens. Analysis of the frequency at which epitopes occur suggests that such cross–reacting proteins will be commonly seen in malaria, without the need to postulate a selective advantage for such cross–reacting

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00923.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryWe have investigated whether a protective immune response occurred in mice infected with a virulent cloned strain ofPlasmodium chabaudi.Animals inoculated intravenously with 10′ parasitized erythrocytes (PE) showed an exponentially increasing parasitemia and died by day 6 of the infection, presenting a pronounced anaemia. Smaller inocula produced a longer pre–patent period but did not change the lethal course of infection, since mice injected with 100 parasites died on day 12. When anaemia was compensated for by red blood cell (RBC) transfusion, infected mice recovered and thereafter exhibited a strong immunity, comparable to that of mice immunized by a drug–controlled infection. The immune response wasP. chabaudispecific, as the mice were fully susceptible to a challenge byP. yoelii.Three transfusions of 5 times 10′ RBC per mouse at 2–day intervals were necessary before all the animals were able to control the infection. Transfusion of a larger number of RBC resulted in a lower anaemia and a delay in reticulocytaemia but, paradoxically, the expression of the immune response was delayed. Three transfusions of 1–2 times 1010RBC enabled three out of eight mice to survive the infection, while six transfusions enabled all the mice to survive. The data suggest that parasitized immature RBC could play an important role in triggering the protective immu

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00924.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryA semi–quantitative analysis of individual human antibody responses to larvalAscarisexcretory 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 ofAscarisis 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 re

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00925.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryWe report here a broad analysis of the excretory/secretory (E/S) products of adultBrugia malayi, collected by in–vitro cultivation of the parasite. Culture media and conditions were optimized, and non–essential amino acids were found to be crucial for efficient protein synthesis under cell– and serum–free culture conditions. A close correlation was found between total protein secretion, phosphorylcholine–bearing antigen release and lactate production on each day of culture, indicating that E/S molecules are actively secreted. Parasites culturedin vitrotake 2–3 days to adjust to the new environment, and show peak levels of secretion at days 3 and 4. The active secretion of phosphorylcholine by the parasite therefore justifies the measurement of this molecule as an indication of active infection, possibly reflecting total worm burdens. By comparing metaboli–cally labelled E/S from male and female worms, several molecules of low mol. wt, namely 10000, 13000, 14 000 and 22 000, together with high mol. wt components of above 12000 were found to be female specific. Tracing the origin of the E/S products, several molecules were also found to be associated with the surface. Among these, there are at least two glycoproteins, 29 000 and 51000 of which the 29000 molecule is a major surface protein. The immunogenicity of the E/S was examined and antigenic cross–reactivity was found with sera from most filarial infections but not with non–filarial nematodiases such as hookworm orTrichi–.nella.However, two molecules of low mol. wt, 15 000 and19000, were not recognized by anti–Onchocercasera and appeared to be potentialBrugia–specificdiagnostic molecules. Possible functional roles of the adult E/S products were examined but we could find no evidence of protease activity in the E/S or glutathione S–transferase activity in either the E/S or

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00926.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryDespite marked pulmonary pathology caused by larval stages of many helminth parasites, little is known about the mechanisms of immune and inflammatory responses to parasites in the respiratory tract. Using bronchoalveolar lavage (BAL) we have retrieved soluble proteins and cells from the respiratory tract of rats given a primary or secondary infection with the nematodeNippostrongylus brasiliensis.Total amounts of different immunoglobulin classes and albumin in BAL fluids and serum were quantitated using an ELISA. Analysis of the cellular component showed an increase in alveolar macrophages, neutrophils, eosinophils and lymphocytes on different days post–infection similar to our earlier findings. A time course study revealed that the concentrations of total protein, albumin, IgG, IgA and IgM in BAL fluids of infected animals were increased from days 2 to 32 after a primary infection. The magnitude of this increase was higher following a challenge infection (secondary) with the same parasite. Moreover, there was also a biphasic increase in total protein, IgG and IgA after secondary infections, with peaks on days 2 to 4 and 11 to 21 postinfection. A comparison of immunoglobulin to albumin ratios in serum and BAL fluids showed that the initial peak of proteins in the lavage was a result of serum leakage and the subsequent peak was due to local secretion of immunoglobulins. These results suggest that in addition to marked BAL cellular reactivity,N. brasiliensisinfection induces an initial vascular and endothelial permeability in the respiratory tract which is soon repaired but followed by local synthesis and secretion of IgG and IgA in the lower respiratory trac

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00927.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryThe influence of the I region of the major histocompatibility complex (MHC) on T–dependent immune responses against a purified schistosome antigen (9B antigen) was investigated. H–2 congenic mice expressing both I–A and I–E antigens (I–E+) showed a higher in–vitro proliferation to 9B antigen as compared to the recombinant strains expressing only I–A (I–E–). These two strains of mice differed both qualitatively and quantitatively in the humoral responses elicited by the purified antigen. Furthermore, in–vivo protection experiments showed that mice which do not express I–E molecules can be partially protected against the disease by prior immunization with the 9B antigen in contrast to their I–E expressing counterparts. The possible role of the I–E molecule in the immune responses elicited duringSchistosoma mans

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00928.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryT–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

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00929.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryWe have produced a panel of human monoclonal antibodies (MoAb) from patients infected withSchistosoma mansoniin 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 antigensin 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.mansoniantibodies 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 toS. mansoniis currently be

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00930.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY