摘要:

SummaryOxidatively stressed red blood cells (RBC) and Plasmodium falciparum‐infected RBC (PRBC) are avidly phago‐cytosed by human peripheral monocytes. Following the ingestion of PRBC the monocytes’ ability to phagocytose PRBC and to generate aggressive oxidative compounds is severely impaired. In the present work the microbicidal and anti‐tumour capacities of monocytes fed with diamide‐treated RBC and PRBC harbouring mature (trophozoite) parasites have been investigated. The capacity of the latter, but not of the former, to phagocytose Escherichia coli and Staphylococcus aureus and to kill them, as well as ingested Candida albicans cells intracellularly, was found to be markedly impaired. Monocytes that have ingested PRBC had a significantly reduced cytostatic and cytolytic activities against a lymphoblastic tumour cell line. Monocytesfed with oxidatively stressed RBC had normal or sometimes even greater anti‐tumour activities. Monocytes that have ingested PRBC showed a reduced capability to produce superoxide following stimulation with phorbol ester. Such impairment in monocyte functions may explain the reduced antibacterial and anti‐tumour activities of monocytes in malaria patients, and could be consequential to their ability to resist bacterial infections and to provide means for the control of tumour development in t

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00579.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryImmunosuppressed mice with heavy Schistosoma mansoni infections suffer from a severe hepatotoxicity reaction soon after the onset of infection patency, and this may be directly consequent upon the failure of the hosts to mount adequate granulomatous responses to embolized parasite eggs. Immune serum or immune peripheral lymphocytes from normal S. mansoni‐infected immunologically intact donor mice were transferred to homologously‐infected syngeneic T‐cell deprived recipients to test the respective capacities of the transferred humoral or cellular immune effector elements to prevent hepatocellular damage and to reconstitute granuloma formation. Transferred immune serum was very effective in preventing liver cell damage, but did not significantly reconstitute the capacity to form granulomas in the recipients. In contrast, mice receiving immune spleen and mesenteric lymph node cells had their capacity to form granulomas around liver‐bound eggs reconstituted, but lymphoid cell transfer was less effective in protecting against hepatocyte damage than serum transfer. Protection of host tissues may therefore not be the main role of the T‐cell mediated S. mansoni egg

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00580.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummarySpleen cells (SpC) and mesenteric lymph node cells (MLNC) from F344 donor rats actively immunized by oral inoculation with Taenia taeniaeformis eggs were syngeneically transferred into previously uninfected recipient rats by intravenous injection. Recipient rats were challenged with eggs after cell transfer. The degree of immunity was assessed by counting the number of growing metacestodes (MC) in the liver and compared with that in controls. Transfer of 2 × 108SpC, obtained from donors immunized for ten or more (but not for three or five) days before cell transfer inhibited the establishment of most of MC. There were approximately 86–88% reductions in MC recoveries. SpC (2 × 108) obtained from donors immunized for ten days inhibited the establishment of most of MC in recipient rats when transferred nought, two, or 24 h (but not 48 h) before egg challenge. Functional cells in the immune SpC were helper T cells W3/25+, OX8−and OX22−. However, immune MLNC obtained from donors immunized for three to ten days before cell transfer had no effect on transferring i

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00581.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryThe neutral and acidic fraction glycolipids of Echinococcus granulosus metacestode tissue compartments were isolated, defined by their chromatographic and antigenic properties, and assessed as to their efficacy as antigens in the serodiagnosis of human hepatic cystic and alveolar echinococcosis, and other helminthiases. Analyses were accomplished by thin‐layer chromatography immunostaining and ELISA. The neutral glycolipid fraction's major carbohydrate epitope was the same as or very similar to that of Taenia crassiceps neutral glyco(sphingo)lipids, as represented by the ‘neogala'‐series core structure. The blood group‐active, carbohydrate epitope P1 was expressed by a number of neutral fraction glycolipid component bands. The reverse‐phase, thin‐layer chromatography‐isolated neutral fraction glycolipid component, designated Ag1, was efficient in the serological discrimination of cystic echinococcosis medium to high‐titred sera. Ag1 did not specifically discriminate low‐titred sera, i.e., other human helminthiases. The detected sialic acid residues of the acidic fraction glycolipids, on enzymatic cleavage, were identified as N‐acylneuraminic acid and terminal. The acidic fraction glycolipids exhibited the paradox of only chemically minor components being antigenic towards cystic and alveolar echinococcosis infection sera. The combined acidic fraction glycolipid components Ra and Rx were capable of serological discrimination between cystic echinococcosis, alveolar echinococcosis and

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00582.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

SummaryThe present study examines the age‐dependency of parasite‐specific isotype responses and antigen recognition profiles of individuals within a Trichuris trichiura endemic community, in order to evaluate the significance of serum antibodies as determinants of observed age‐related patterns of infection intensity. A high degree of individual heterogeneity is observed in isotype responses to separated T. trichiura antigens by Western blot. Recognition by IgG1antibodies exhibits marked age‐dependency. The age‐profiles of IgG1responses to selected antigens of 16–17 kDa and 90 kDa molecular weight reflect the age‐related changes in current infection intensity at the population level. Similarly, mean age patterns of IgG2responses to a 90 kDa antigen, and mean IgG4responses to a 16–17 kDa antigen reflect mean infection levels. IgG3responses are negligible, and for methodological reasons, both IgE and IgM specificities are not presented. IgA responses to separated antigens of 16–17 kDa and 90 kDa, exhibit age‐profiles which may suggest the development of an IgA‐mediated acquired resistance to T. trichiura with age. IgA levels remain elevated throughout early adulthood, when infection intensity levels markedly decrease, supporting the hypothesis that IgA antibodies may be significant in generating the convex nature of the age‐infection

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00583.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

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 th

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1993.tb00584.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY