摘要:

SummaryThe infraction betweenEntamoeba histolyticatrophozoites and cells of the immune system was studiedin vitro. Both immune as well as non‐immune mononuclear cells (MNC) to some extent were capable of exerting a cytotoxic effect onE histolyticatrophozoites. Incorporation of immune serum directed against the trophozoites in the reaction mixture resulted in a marked increase in the killing capacity of MNC. Highest killing was observed (96·7 ± 1·04%) with MNC obtained from animals immunized with fraction‐1(F‐1) of the crude amoebic extract in association with anti‐F‐1 serum. This cytotoxic event was found to be independent of complement involvement and required very low antibody concentrations. This antibody‐dependent cellular cytotoxicity againstE. histolytica in vitrowas found to correlate well with the results of experiments reported earlier by us and others where a high degree of protection has been shown alter vaccination of animals with F‐1 followed by challenge with highly virulent strains ofE. histolytica.

ISSN:0004-945X    

DOI:10.1038/icb.1985.1

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryP. falciparummalaria was culturedin vitroin the presence of sera from patients with cerebral malaria, meningitis and also after choloroquine administration. Intra‐erythrocytic parasite damage was seen by light and electron microscopy. The significance of the results is discussed with relevance to non‐specific immune mechanisms, and the damage induced by these mechanisms compared with that from chloroquine.

ISSN:0004-945X    

DOI:10.1038/icb.1985.2

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryWhen BALB/c mice and athymic (nude) mice are injected intraperitoneally (i.p.) with pneumococcal type III polysaccharide (SIII), their antibodies as measured by passive haemagglutination (HA) are inhibited more easily by high doses of SIII than antibody measured by passive haemolysis (HL). The HA activity, due mainly to a highly avid non‐complement‐fixing (NCF) type of IgM, was further distinguished from the HL activity (CF‐IgM, or CF‐IgM plus CF hybrid IgM/A anti‐SIII antibodies) by the failure of the NCF‐IgM anti‐SIII to bind to protein‐A ofStaphylococcus aureus(Sa). High‐dose tolerance in the HL anti‐SIII antibody response of BALB/c and athymic mice was induced only in the absence of circulating NCF‐IgM anti‐SIII antibodies. The presence of NCF‐IgM anti‐SIII antibodies formed to multiple daily increasing amounts of SIII, commencing with 0·01 μg SIII, decreased the magnitude of the HL anti‐SIII response to subsequent daily increments of SIII antigen injected into BALB/c and athymic (nude) mice. Thus, the effect on the HL anti‐SIII response was independent of T‐cells. The concomitant administration of NCF‐IgM anti‐SIII rendered SIII less tolerogenic in primed mice. In contrast to the HL activity, the NCF‐IgM anti‐SIII antibodies were induced to low doses of SIII, conferred protection against viable pneumococci, but did not precipitate the soluble antigen in agar. It is proposed that immune paralysis (as defined by the failure of SIII‐injected mice to resist pneumococci challenge) is not necessarily a condition of total unresponsiveness but is due to an absence of protective NCF‐IgM anti‐SIII antibodies. Thus, immune paralysis can co‐exist with either the presence or absence of non‐protective CF‐IgM or CF‐IgM/A anti‐SIII antibodies.

ISSN:0004-945X    

DOI:10.1038/icb.1985.3

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryPrevious studies on the antigen‐presenting of activity of alveolar macrophages (AM) have been restricted to the use ofin vitroassay systems, and have generally shown suppression of T cell activation by these macrophages. The present study exploits the rapid adaptability of AM to changes in oxygen tension, which facilitates their transfer to other tissues in a functional state. Employing this rationale, antigen‐pulsed AM were shown to trigger T cell‐dependent immune responses following subcutaneous or intraperitoneal inoculation, while suppressing similar responses in tissue culture.

ISSN:0004-945X    

DOI:10.1038/icb.1985.4

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryThe intestine of the foetal lamb was exposed to large quantities of δ‐globulin (IgG) by prolonged intra‐duodenal infusion, and absorption of intact IgG, with transfer to the lymph, continued undiminished, i.e., there was no evidence of closure. The rate of proliferation of the intestinal epithelium of the foetal and newborn lamb was measured using mitotic indices and localised labelling with (3H)‐thymidine (TdR). In the foetus, cell division in the crypts occurs at a lower rate than the newborn (p<0·001) and there is very slow replacement of the intestinal epithelium. In the newborn lamb, a portion of the small intestine was incubatedin vivowith TdR and the progress of labelled cells from the crypts upwards along the villi estimated, using autoradiography of serial biopsies from the same animal. A front of mature, digestive epithelium could be seen advancing up the villi, displacing the immature foetal type of cell which was capable of transfer of intact IgG to the lymphatics of the intestine. The evidence presented supports the hypothesis that immediately after birth the intestinal epithelium of the lamb begins to be replaced by a digestive type of cell, and the layer of cells responsible for absorption of colostral antibodies progressively disappears from the villi, resulting in closure.

ISSN:0004-945X    

DOI:10.1038/icb.1985.5

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryAlveolar macrophages from NZW rabbits were intrinsically toxic to 6 xenogeneic cell lines and toCandida albicans in vitro.Macrophage‐mediated candidacidal activity, but not cytostasis (inhibition of [3H] thymidine incorporation by target cells) or cytotoxicity (reduction in target cell number), was enhanced by prior injection of rabbits with Freund's complete adjuvant (FCA).Compared with alveolar macrophages, peritoneal macrophages were less candidacidal (medianC. albicanskilled, 24% versus 16%. p<0·01). In contrast to alveolar macrophages, peritoneal macrophages were not consistently cytostatic or cytotoxic. Only candidacidal activity was enhanced in FCA‐elicited peritoneal macrophages (medianC. albicanskilled 28% versus 16% for resident peritoneal macrophages, p<0·01).Microbicidal concentrations of a cationic peptide produced by rabbit alveolar macrophages (MCP‐1, 25–100μg/ml) did not inhibit growth of 4 murine cell linesin vitro.Macrophage‐mediated cytostasis and cytotoxicity were not enhanced by culture with exogenous MCP‐1. Macrophage‐mediated cytostasis was also unchanged in cultures containing 10−52’deoxycytidine.We conclude that rabbit macrophage populations are restricted in their expression of cytostatic and cytotoxic functions, that microbicidal activation can occur independently of cytotoxic activation and that in this system mechanisms of macrophage‐mediated cytotoxicity to xenogeneic target cells are independent of MCP‐1 and thymidine.

ISSN:0004-945X    

DOI:10.1038/icb.1985.6

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryThe development of the zinc‐deficient rat embryo has been studiedin vitrousing embryo culture techniques. Normal 9·5 day embryos cultured for 48 h in serum Obtained from zinc‐deficient rats grew and developed to the same extent as those cultured in zinc‐replete serum. Embryos from dams which had been fed a zinc‐deficient did since mating were also removed for culture. Such zinc‐deficient embryos cell into two broad morphological categories One group appeared identical to the normal embryos, while the others had apparently normal visceral yolk sacs but small embryonic poles and retarded or abnormal embryonic development. Culture the first group in either zinc‐deficient or replete serum produced morphologically normal embryos: however, those which appeared abnormal at day 9·5 were grossly malformed after 48 h incubation in either sera. When embryos were cultured in the presence of Zinc, the most severely affected zinc deficient embryos accumulated as much zinc as the zinc‐replete in and apparently unaffected zinc‐deficient embryos, indicating that the malformations do not arise from an inability of the embryo or yolk sac to accumulate zinc from the surrounding fluid the results front these studies suggest that the teratogenic effects of zinc deficiency cannot be induced by direct culture of zinc‐replete embryos in zinc‐deficient serum. Furthermore, it would appear that maternal zinc deficiency can exert its teratological influence prior to day 9·5 of gestation and that these effects arc not readily reversible.

ISSN:0004-945X    

DOI:10.1038/icb.1985.7

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryOxygen consumption (VO2) was measured in Porton albino rats using a closed circuit apparatus. The groups studied were controls, cold‐adapted animals, and those which had accumulated brown adipose tissue as a result of a cafeteria diet with a high energy content. It was possible to show in each group studied a difference in VO2according to the time of day at which it was measured. This was consistent within each group studied. The diurnal variation shown (higher in the morning than in the afternoon) is characteristic of nocturnal animals. Measurement of VO2then must be made within the same time‐period or integrated over 24 h. Spurious correlations may otherwise occur.

ISSN:0004-945X    

DOI:10.1038/icb.1985.8

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryRabbits were fed a stock or atherogenic diet for a period of fourteen months. Half of each group of rabbits was bilaterally vasectomized while the other half underwent sham vasectomy. The level of plasma cholesterol was significantly elevated following vasectomy in stock diet‐fed rabbits. Atherogenic diet feeding caused marked elevation of plasma cholesterol in both vasectomized as well as sham‐vasectomized animals. At the termination of the experiments, aortic cholesterol in stock diet‐fed vasectomized rabbits remained unchanged, but this was increased in both vasectomized and sham‐vasectomized atherogenic diet‐fed animals. Aortic sudanophilia, atherosclerotic plaque size and coronary atherosclerosis index were significantly increased in vasectomized atherogenic diet‐fed rabbits as compared to their controls. In stock diet‐fed vasectomized rabbits no macroscopic or microscopic lesions were seen even in the presence of mild hypercholesterolaemia.

ISSN:0004-945X    

DOI:10.1038/icb.1985.9

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY

摘要:

SummaryAn improved method of producing hepatic amoebiasis in hamsters has been developed. A serially liver‐passaged strain ofEntamoeba histolyticafrom experimentally‐infected hamsters was used for infection. Small pieces from the infected liver were examined for the presence of amoebae and contained approximately 20,000 active trophozoites per piece. Such liver pieces, when used as an inoculum, produced infection in all of the animals, The method has been successfully employed for screening of known amoebicides such as emetine, dehydroemetine, metronidazole, tinidazole, chloroquine, mepacrine, amodiaquine and ambilhar.

ISSN:0004-945X    

DOI:10.1038/icb.1985.10

出版商:Nature Publishing Group    

年代:1985

数据来源: WILEY