摘要:

SummarySchistosomiasis is a chronic disease afflicting hundreds of millions of people throughout the world against which there is as yet no effective vaccine. In the present study we tested the effect of the immunomodulator muramyl tripeptide phosphatidyl ethanolamine (MTP‐PE) on the survival ofSchistosoma mansoni‐infected mice and on the induction in them of schistosomulicidal macrophages. Mice exposed to 80 cercariae each and then treated with MTP‐PE showed prolonged survival following either single or repeat infection. The treatment with MTP‐PE, when initiated 70 days post the schistosome infection, diminished significantly the mortality of infected mice over an observed period of 110 days. In terms of treatment efficacy there was no evident difference between the intravenous and intraperitoneal mode of administration of the drug. MTP‐PE treatment significantly reduced granuloma size and markedly diminished liver damage as judged by the lower levels of alkaline phosphatase in the serum. Such treatment exerted no significant effect on the spleen or liver weight in infected mice nor on the worm burden resulting from either a single or double infection. In infected and non‐treated mice, schistosomulicidal macrophages appeared after 8–10 weeks of infection. In infected mice treated with MTP‐PE there was an accelerated appearance of such macrophages and these exhibited a greater cidal effect on the schistosomula. These immunostimulatory and life‐prolonging effects of MTP‐PE onS. mansoni‐infected mice might indicate an effect of this reagent on cells involved in the

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00011.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryThe immunological basis of resistance toBrugia pahangiinfection in rats was studied. Infections were investigated in athymic rnu/rnu rats and in rats treated with the immuno‐suppressive agents cyclosporin A (CsA) or cyclophos‐phamide (Cy). The recovery of adult worms in normal rats was 1–2% in comparison to 12.2% recovery in athymic rats. CsA and Cy treated rats did not have increased adult worm burdens. Microfilarial (Mf) levels (expressed as Mf per ml per adult worm) were highly elevated in both athymic and Cy treated rats but not in CsA treated rats. IgG and IgM levels toB. pahangiantigens were severely depressed in both athymic and Cy treated rats. IgG levels but not IgM levels were abrogated in CsA treated rats. These results implied that control of larval establishment or adult killing, and regulation of Mf levels are separate T‐cell dependent mechanisms and act independently of IgG antibody. Control of Mf levels is associated with a specific IgM response which is Cy sensitive but CsA re

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00012.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummarySerum effects on gametocyte infectivity, that is, transmission blocking/enhancing immunity, were measured in the sera of 196 acutePlasmodium vivaxpatients who were residents of a malaria region in Kataragama, southern Sri Lanka. Direct mosquito feedings were also performed on 170 of these patients. Sera of about 48% of patients suppressed gametocyte infectivity significantly (by more than 75%) and of a smaller proportion (12%) had pronounced infectivity enhancing effects. Transmission immunity did not increase with age of patients, rather, immunity tended to be higher in younger patients. Data suggest that immunity levels are boosted by reinfections only if they occur within a period of 4 months from the previous infection, i.e., that immune memory for boosting does not last beyond 4 months. Enhancing effects in the sera of patients correlated with the absence of gametocytes at the time of investigation suggesting that enhancement occurs early during the course of a blood infection, and blocking later, when serum antibodies reach higher levels. The blocking and enhancing effects of a serum appears to depend not only on the antibody concentration in serum, but also on the intrinsic infectivity of the parasite isolate against which it is tested: thus, infectivity enhancing effects were potentiated by low intrinsic infectivities of the parasite isolate. The direct infectivity of patients to mosquitoes correlated with transmission immunity indicating that transmission immunity is an influential factor determining infectivity of malaria patients.

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00013.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryTo determine the role of interferon‐gamma (IFN‐γ) in the activation of macrophages to killEntamoeba histolyticatrophozoitesin vitro, C57BL/6 mice were injected with various doses of recombinant IFN‐γ (rIFN‐γ) by either the intravenous, intraperitoneal or intramuscular routes. Mice were treated with doses of rIFN‐γ ranging from 101to 105units. Twenty hours later, peritoneal macrophages were harvested from the treated animals. Macrophage monolayers were prepared and their in vitro cytotoxic activity against a virulent strain ofE. hystolytica(IP:0682:1) was determined. Amoebicidal activity was determined by counting the number of dead trophozoites by Trypan Blue exclusion in cultures containing macrophages and amoebic trophozoites which were incubated together for 4 h. Both intravenous and intraperitoneal treatment resulted in the recovery of macrophages from the peritoneal cavity which exhibited amoebicidal activityin vitro. Peritoneal macrophages harvested from mice that had been treated intraperitoneally or intravenously with rIFN‐γ, however, showed significantly more amoebicidal activity in comparison to macrophages harvested from animals treated intramuscularly. There was a dose dependent relationship between the concentration of rIFN‐γ used to activate macrophagesin vivoand the number of dead trophozoitesin vitro. In addition, these results confirm our previous observations that treatmentin vitrowith rIFN‐γ can activate murine peritoneal macrophages to kil

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00014.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryC57B1/10 ScSn mice infected withToxoplasma gondiideveloped a meningoencephalitis, characterized by areas of tissue destruction and cellular infiltration including foci of neutrophils. Large numbers of cyst stages were found throughout the brain but were not always associated with inflammation. The use of immunocytochemistry to detect glial fibrillary acidic protein, an astrocyte specific marker, showed a widespread astrocyte activation. This was particularly prominent in areas of intense inflammation but cysts were negative for glial fibrillary acidic protein, indicating that astrocytes were not host cells for the bradyzoites. The use of the polymerase chain reaction to assist in the amplification of total brain RNA allowed the characterization of the cytokines being produced locally within the brains of infected animals. β‐ actin transcripts were detected in all of the uninfected and infected mice. In only one of the seven uninfected control mice were other transcripts found. Transcripts for tumour necrosis factor‐α, interleukin‐1α and β, interleukin‐6, macrophage inflammatory protein‐1 and interferon‐γ as well as the CD4 marker were detected in all of the infected mice. However, transcripts for IL‐2 and IL‐4 were not present. Several of the cytokines present are capable of initiating meningeal inflammation and may play a role in the immunopathogensis of toxo

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00015.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryEight Swiss strains ofBorrelia burgdorferi, with various protein profiles and the North‐American strain B31 were artificially introduced intoIxodes ricinusticks and reisolated 10 days later. All isolates were subsequently examined by SDS‐PAGE analysis. Comparing initial isolates with the reisolates, we observed that 7 out of 9 strains changed their protein pattern with respect to the major proteins OspA, OspB and the 22 kDa protein after passage in the tick. The strains NE2, NE4 and NE83 with the initial phenotype of OspA and 22 kDa proteins changed to the phenotype of OspA and OspB, the strains B2 and NE202 with the initial phenotype of OspA acquired an additional protein of 22 kDa and the strain NE58 with the initial phenotype of OspA also acquired a protein of 22 kDa. Examination of these isolates by Western blot analysis demonstrated that the reaction with the monoclonal antibody H5332 and a monospecific polyclonal antibody PoAb/anti‐22 kDa differed between the initial isolates and the reiso

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00016.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryThe distribution of granule‐specific sheep mast cell proteinase (SMCP). was assayed by immunocytochemistry and quantified by immunoassay in sheep immune toHaemonchus contortus. Repeated infection withHaemonchuslarvae over 10–12 weeks induced a pronounced mucosal mastocytosis, including intraepithelial globule leukocytes (GL), which. 7 days after ceasing this dosing regime, was associated with the inability of incoming larvae to establish within the abomasal mucosa. Loss of this resistance, due to the cessation of stimulation withHaemonchuslarvae 84 days previously or to treatment of sheep with cortico‐steroid. was associated with a marked decline in mast cell density and concentrations of SMCP in abomasal mucosal tissues. Nevertheless, larvae also failed to establish in immune sheep rested from challenge 42 days previously and in which mast cell counts were not significantly different from those of control sheep. A small, but significant, release of SMCP was demonstrated in gastric mucus from immune sheep following larval challenge, whereas little or no SMCP was detected in mucus from naïve a

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00017.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryBALB/K mice are usually resistant to infection with the intestinal nematode parasiteTrichuris murisand exhibit a Th2 dominated (IL‐5, IL‐9) response. Conversely in B10.BR mice, which are unable to expelT. muris, Thl type (IFN‐7producing) cells predominate. We have manipulated the course of infection in these two strains of mice such that the period of host‐parasite contact is extended in the former and curtailed in the latter. Extension of host‐parasite contact in BALB/K mice beyond normal (day 21) resulted in the modulation of cytokines produced byin vitroconcanavalin A (Con‐A) stimulated MLNC away from IL‐5 and IL‐9 (Th2‐type cytokines) in favour of the Th1‐type cytokine IFN‐γ. Curtailment of host parasite contact in B10.BR mice to less that 21 days resulted in elevated production of IL‐5 and IL‐9 by MLNC in the absence of elevated IFN‐γ levels. Thus modulation of expulsion phenotype also modulates cytokine production by T‐cells in the MLN draining the site of infection, with a Th2 response being associated with resistance and a Th1 type response with the inability to expel the parasite. Mechanisms by which the modulated cytoki

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00018.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY

摘要:

SummaryNine human monoclonal antibodies (MoAbs) recognizing 7 different antigenic structures of blood‐stages of the human malarial parasite P.falciparum(Pf) were produced by Epstein‐Barr virus transformed B‐cell lines (EBV‐TCL) with or without fusion to the lymphoblastoid cell line KR4. The peripheral blood B‐lymphocytes were obtained from 8 Gambian donors immune to Pf malaria. Two of the EBV‐TCL could be expanded and maintained for more than 6 months but neither one could be cloned. Six additional EBV‐TCL were stabilized after fusion with the KR4 lymphoblastoid cell line. All resulting hybridomas permitted easy cloning. Some of the MoAbs produced distinct fluorescent staining patterns of asexual Pf blood‐stage parasites when using high‐resolution digitized video‐intensified fluorescence microscopy. Antigens on 195 kD and 155 kD proteins were recognized by 3 and 1 MoAb, respectively, using Western blotting and immunopreci

ISSN:0141-9838    

DOI:10.1111/j.1365-3024.1992.tb00019.x

出版商:Blackwell Publishing Ltd    

年代:1992

数据来源: WILEY