摘要:

Human isotype specific antibody responses to a recombinant π‐class glutathione S‐transferase (Ov24) fromOnchocerca volvuluswere assesed by ELISA, using a large and well‐characterized bank sera (n=238) from an hyper‐endemic area of moderate intensity from Sierra Leone. IgG1, IgG4 and IgA responses, but neither IgG2 nor IgE response, to Ov24 were detected in infected subjects. The relationships between Ov24 antibody levels and skin microfilarial density, number of nodules, age, sex, eosinophil counts and clinical sign of reactive and chronic pathology were analysed using Pearson’s correlation coefficient. Significant correlations between both IgA and IgG3 antibody levels and age were found (P<0.01). Although no firm conclusions could be drawn from this study sample regarding the relationships between antibody levels and parasite load or clinical status, a negative correlation (P=0.06) between Ov24 IgG3 antibody levels and microfilarodermia

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-124.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

Interferon gamma receptor knockout mice developed a chronic infection when inoculated with spores ofEncephalitozoon intestinaliswhich is a cause of intestinal microsporidiosis in AIDS patients. The infection was evaluated by enumeration of the spores of the parasite shed in the stools, histological examination and follow up over a period of six months. A dose‐response was demonstrated since higher numbers of spores were excreted and more infection sites were found in mice which were given an increased quantity of parasites. In infected wild type mice, the number of excreted spores decreased until day 16 post‐inoculation, then spores were detected sporadically in low numbers. These data confirmed the role of IFN‐γ in the control ofE. intestinalisinfection. The infection was not lethal suggesting that other factors are involved in regulation of the parasite infection. This model, with the long survival time of the animals together with the measurable quantity of spores shed in the stools will be useful for testing potential therapeutical

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-128.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

The antibody response was followed weekly during 68 weeks in 17 Balb/c mice intraperitoneally (i.p.) infected with 2000Echinococcus granulosusprotoscoleces (PSC) and in three mice i.p. immunized with 2000 dead PSC. Antibodies against hydatid cyst fluid (HCFA) and its peptidic (periodate‐resistant) and carbohydrate (periodate‐sensitive) epitopes were titrated by ELISA. Avidity and the antigen recognition pattern of antibodies were also analysed during infection and immunization by ELISA and immunoblot, respectively.The antibody response of infected mice showed quantitative and qualitative variations during infection, since both titre as well as recognition of peptide and carbohydrate epitopes in HCFA depended on time post infection. No avidity maturation was evident during the course of infection. Sera from infected mice recognized the 38 kDa subunit of Ag5 but did not react with the 8 kDa subunit of AgB. On the contrary, the antibody response of immunized mice showed only one peak of antibodies that recognized both peptidic and carbohydrate epitopes of HCFA. In addition, sera from these mice recognized mainly 60 and 110 kDa bands. Our results suggest that: a) avidity and antigen recognition patterns of antibodies in mice treated with live PSC are different from those treated with dead PSC; b) antibodies against HCFA glucidic or peptidic epitopes appear at different times post in

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-125.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

C57BL/6 and Balb/c mice were immunized with ultraviolet‐irradiated cercariae of Egyptian strains ofSchistosoma mansoniandS. haematobium, challenged with non‐irradiated cercariae of the homologous or heterologous species, and assayed for protection against challenge infection by comparing the adult worm burdens of immunized and non‐immunized mice. Homologous protection (per cent reduction in worm recovery) ranged from 56% to 69% forS. mansoniand 88% to 99% forS. haematobium. Significant heterologous protection was consistently induced againstS. haematobiumby immunization withS. mansoni, but not against S. mansoni by immunization withS. haematobium. These results are discussed in relation to those of previous studies and in terms of implications for vaccine develo

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-129.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

Three alleles of the FC27‐type allelic family of the MSP2 gene of the malaria parasitePlasmodium falciparumhave been sequenced from parasites from the field (The Gambia and Tanzania). These alleles lack the 12 amino acid repeat units which are usual in this family of MSP2 alleles. We have investigated the recognition by sera from an endemic area (The Gambia) of three recombinant MSP2 proteins that have 5, 1 and no copies of this repeat region. Antibody recognition of these recombinant proteins varied according to the number of repeats present. High titre antibody levels were seen with most sera using the recombinant protein with 5 × 12‐mer repeats, whereas only low responses were measured using proteins containing 1 or no 12‐mer repeats. Several sera entirely failed to recognise the protein which lacked 12‐mer repeats. The data suggest that variation in the number of tandem repeat sequences could allow the parasite to avoid high avidity antibody binding and this may allow escape from immune

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-137.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

A spectrum of clinical manifestations is a feature of human lymphatic filariasis. The acute disease is characterized by periodic and self limiting episodes of adenolymphangitis, fever and associated constitutional symptoms, while the chronic disease includes long lasting manifestations such as lymphoedema and/or hydrocoele. The microfilariae carriers are generally free of clinical symptoms. In the present study circulating Tumour Necrosis Factor (TNF‐α) was measured in human bancroftian filariasis with different clinical manifestations. Significantly elevated levels were observed only in patients with acute disease and not in microfilariae carriers or in patients with chronic manifestations. A detailed analysis of the acute cases indicated an absence of correlation between TNF‐α levels and duration of the episodes. However, a significant positive correlation was observed between the severity of the disease and the TNF‐α levels. About 85% of the acute cases with severe manifestations showed raised levels of TNF‐α while only 6.5% of mild cases showed such levels. Manifestation of fever was also significantly associated with higher levels of TNF‐α—while 80% of acute cases with fever had significant levels only 24% of acute cases without fever had high levels of TNF‐α. Based on these observations we propose a mediatory role for TNF‐α in acute filariasis and the possible use of TNF‐α inhibitors for clinical

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-126.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

We have shown previously that at the time of peak primary parasitaemia ofP. chabaudiinfection in NIH mice, significant levels of nitric oxide are produced, detectable as nitrate in the serum, and that these contribute to the protective immune response to infection. Here, we demonstrate that following reinfection, mice show a markedly diminished ability to produce nitrate. However, if mice are treated with L‐NG‐monomethyl arginine specifically to block nitric oxide metabolism during the primary infection, and are then reinfected, production of nitrate is restored to levels approaching those attained at peak primary parasitaemia. These experiments, together with others we have reported, indicate that whereas nitric oxide appears to play a significant role in control of the primary parasitaemia ofP. chabaudiinfection, it performs no such function during subsequent patent parasitaemias. Furthermore, they suggest that factors as yet unknown may regulate nitric oxide activity during malaria infection, such that under normal circumstances its production comes under strict control. This is exemplified by the observation that after the burst of nitric oxide activity that coincides with peak primary parasitaemia, there follows a prolonged period of immunological tolerance during which nitrate levels remain low even at secondary challenge infection. This tolerized state is lifted only several months after initial infection, when the nitric oxide activity at reinfection appears to correlate with the size of the parasite challenge and the presence of a patent parasitaemia. The implications of these findings for protective immunity to malaria, malarial immunosuppression, and immunoregulation in general, are discus

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-127.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY