摘要:

SummaryLow numbers of parasites from cloned lines of the rodent malaria parasites,Plasmodium chabaudi chabaudiAS andP. yoelii yoeliiA, injected into CBA/Ca mice produce acute but usually self–limiting infections. During crisis, i.e. 1–2 days after peak parasitaemia, ‘pre–immune’ mice experiencing such ‘background’ infections were reinfected intravenously with homologous parasites or parasites of heterologous strains or species.P. c. chabaudiAS pre–immune mice controlled an AS challenge with essentially the same kinetics as the background infection. Reinfection of AS pre–immune mice with the heterologous (CB and IP–PCI)P. c. chabaudistrains orP. chabaudi adamiDS had little effect on the initial growth of these parasites, although eventually the parasitaemia was controlled. In contrast, a partial inhibitory effect on the growth ofP. vinckei lentumDS was evident. Challenge with the non–lethal (A) or lethal (YM) variants ofP. y. yoeliiresulted in an increase in both the growth and virulence of these parasites.P. y. yoelii Apre–immune mice controlled a homologous challenge, but were less effective at controlling the YM variant. In addition, they were unable to clear rapidly aP. c. chabaudiAS orP. v. lentumDS challenge. Both the multiplication and virulence ofP. bergheiANKA were enhanced. These findings demonstrate that resolution of the primary acute parasitaemia inP. c. chabaudiAS– andP. y. yoeliiA–infected mice is predominantly mediated by species– a

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00644.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryA gene encoding a previously undescribed antigen ofPlasmodium falciparumhas been isolated from a genomic expression library by use of a pool of human immune sera. Northern blot analysis indicated that the gene is expressed at the late stages of the intra–erythrocytic cycle. This antigen, 332, contains a series of degenerated amino acid repeats. Human antibodies affinity–purified on the 332 recombinant antigen reacted with a family of parasite proteins that are products of different genes. We identified antigens 11.1 and Pf 155–RESA as members of this family and confirmed, using a human monoclonal antibody, the presence of cross–reacting determinants. The sequences of these antigens also share some structural homologies. The significance of this family of blood–stage antigens is

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00645.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryA sexual stage–specific protein ofPlasmodium falciparumwith a Mrof 25 000 is one of the target antigens of transmission–blocking antibodies. The contributions of tertiary structure and post–translational modifications (glycosy–lation and acylation) to the structure of the epitopes on this protein were the subject of detailed investigations. After modification of the three–dimensional structure and modification or cleavage of carbohydrate groups and linked fatty acids, the immunological reactivity was investigated by three different techniques: (i) immunoprecipitation of radiolabeled proteins, (ii) enzyme–linked immunosorbent assay (ELISA), and (iii) Western blotting. The results of the experiments indicate that the immunological reactivity of the major epitopes on the 25 kD protein, including the epitope involved in transmission–blocking immunity, are dependent on the tertiary structure of the protein and on the presence of linked fatty acids, but not on the presence or absence of carboh

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00646.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryLymphoblastoid cell lines, infected and transformedin vitroby a Moroccan stock ofTheileria annulata, infected and immunized susceptible taurine cattle, at cell doses of 108, 106, 104and 102, regardless of whether the recipients were Bo LA matched or mismatched to the donor cell line. The MHC relationship between the cell line and recipient did affect the severity of the clinical response to cell line immunization which may reflect differences in the specific priming of the immune response. At the highest cell doses the BoLA–mismatched recipients reacted more severely than the BoLA–matched. This study shows that, unlike the closely related parasiteT. parva, there is no histocompatibility barrier to immunization usingT. annulata–infectedcell lines which could be achieved with as few as 102allogeneic infected cells. The role of MHC compatibility between cell line and recipient in the priming of a protective immune response is disc

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00647.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryTwo groups of animals were immunized with either 106autologous or 106allogeneicTheileria annulata–nfected lymphoblastoid cells culturedin vitro.The development and specificity of cytotoxic cells generatedin vivowere measured throughout immunization and challenge using a panel of target cells that were eitherTheileria–fected or uninfected blast cells of known bovine lymphocyte antigen (BoLA) specificities. After inoculation of the cell lines the two groups showed distinct differences in both their clinical responses and the target specificity of the cytotoxic cells detected. The allogeneicT. annulatacell line recipients showed a very mild clinical response, and on day 9 after inoculation a strong cytotoxic response was detected. The response appeared to be directed against the allogeneic major histocompatibility complex (MHC) antigens of the inoculated cell line in some form of graft rejection response. By day 23 the predominant cytotoxic response was directed against the recipient animals' own cells infected with the parasite. In contrast, the autologousT. annulatacell line recipients showed very severe clinical reactions, and low levels of cytotoxicity were detected. The cytotoxicity was directed against parasite–infected targets but did not appear to be MHC restricted until day 20. Both groups were immune to a heterologous sporozoite challenge that proved lethal to two susceptible control animals, and on day 10 after challenge a peak of cytotoxicity was detected which was directed against the autologous infected target cell. This would suggest that this cytotoxic response was MHC restricted and was also cross–reactive between the heterologous parasite stoc

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00648.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryA monoclonal antibody raised against a non–variable surface antigen ofTrypanosoma brucei rhodesienseprocyclic trypomastigotes was used to develop an antigen detection enzyme immunoassay for the diagnosis ofrhodesiensesleeping sickness. The assay was evaluated using 211 sera from clinically suspected cases: 142 from parasitologically proven cases and 69 from patients who were negative on parasitological examination. The test was positive in 128 out of 142 parasitologically proven cases. The negative cases may have been in the early stages of the disease, or may represent patients with antibody levels sufficient to prevent detection of antigen. Of particular significance, however, was the finding that eight of the 69 patients with undiagnosed disease were antigen positive despite the negative parasitological findings. Since false–positive reactions were not observed with blood donor sera, or with sera from malaria, schistosomiasis and leishmaniasis patients, it is reasonable to conclude that the eight antigen–positive patients were actual cases of sleeping sickness. The remaining 61 cases who were negative for both parasitaemia and antigenaemia may conceivably represent the variety of diseases whose clinical manifestations resemble those ofrhodesiensesleeping sickness. The antigen detection method would thus not only be complementary to parasitological diagnosis, but essential for correct diagnosis in certain stages of the di

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00649.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryGenetically based differences in the antibody responses to the large intestinal nematodeTrichuris muriswere studied in two groups of H–2 congenic strains of mice that differed in their relative resistance to infection with this parasite. The primary antibody response to parasite excretory/secretory (E/S) antigen was predominantly an IgG response with the strains forming two distinct groups, defined by their genetic background. The more susceptible B10 genetic background mice had strikingly higher antibody levels than mice of the BALB genetic background. Superimposed upon these background effects were clearly defined influences attributable to H–2–linked genes, strains which differed genetically only at H–2 loci exhibiting differences in the kinetics of the antibody response. Only B10.G and B10.BR mice showed any great increase in IgM levels post–infection. No IgA specific to E/S antigen was detected in the peripheral circulation of any strain at any time post–infection. Antibody responses to a 40–43 kD antigen revealed clear H–2–linked gene effects, with mice sharing the H–2khaplotype (B10.BR, BALB/K) exhibiting considerably higher total antibody levels than strains expressing other haplotypes; mice of the H–2dhaplotype (BALB/c, B10.D2/n) responded very weakly to this antigen. A Western blot analysis of antigen recognition by antibody revealed similarities between the mouse strains in their total antibody responses toT. murisE/S antigen. However, immunoprecipitation studies showed that in general the more susceptible B10 congenic strains had wider spectra of antigen recognition than the BALB congenics. Strains sharing the same H–2 haplotype had dissimilar antigen recognition profiles, but strains sharing the H–2bhaplotype (B10, BALB/B) recognized a low mol. wt antigen (20–23 kD) not recognized by any other strain, suggesting an exclusively H–2brestriction in the recognition of this antigen. These results support the conclusion that both H–2–linked and background genes play important roles in controlling the humoral im

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00650.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY

摘要:

SummaryHuman peripheral blood monocytes from normal donors were isolated by differential centrifugation and culturedin vitroin hydrophobic Teflon–coated tissue culture bags. Cells were harvested between 0 and 10 days and tested for their ability to kill schistosomula ofSchistosoma mansoniin an in–vitro cytotoxicity assay. Freshly isolated, unstimulated monocytes demonstrated minimal cytotoxic capability. However, this was increased if the cells were pretreated with human recombinant gamma interferon (IFN–γ), or with specific anti–5.mansoniantiserum. As the monocytes maturedin vitrothere were marked increases in the levels of antibody–independent killing of schistosomula. Monocytes grownin vitrowith IFN–γ (104u/ml) took 2–3 days to develop almost maximal cytotoxicity (mean 94% kill of schistosomula). In contrast, unstimulated monocytes (no IFN–γ) took between 5 and 7 days to achieve comparable cytotoxicity (mean 99% kill). Killing of the schistosomula was dependent upon a high effector to target ratio, and was a relatively slow phenomenonin vitro, parasite attrition occurring between 17 and 36 h. Supernatants from cytotoxic macrophages were ineffective in mediating cytotoxici

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1989.tb00651.x

出版商:Blackwell Publishing Ltd    

年代:1989

数据来源: WILEY