摘要:

A number of reports have suggested that the spleen plays a key role in the regulation of immunity to malaria but the role, if any, of other tissues is less clear. Furthermore, numerous functional changes occur in the spleen following malaria infection and it is not known whether the spleen’s role relates primarily to its content of malaria‐specific lymphocytes or to the altered structure and function that has occurred. To address these issues we have generated splenic chimeras by transplanting spleens betweenPlasmodium berghei‐immune and naive rats. In the absence of a functional spleen, specific immune responses from both isolated splenic and non‐splenic cells can partially control infection. However, an immune spleen in a naive rat can solidly protect the animal from malaria and a normal spleen in an otherwise immune rat can provide enhanced protection over the non‐splenic state. Thus, in the presence of functional splenic architecture both splenic and non‐splenic malaria‐specific lymphocytes operate more effectively. However, these studies do demonstrate an important role for non‐splenic tissue in immunity at least forP. bergheiin the rat. The study could have important implications for induction of protective immune responses by vaccination and suggests that malaria‐specific lymphocyte responses induced in the periphery following vaccination could interact with parasites in both spleen‐dependent and sple

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-117.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

In tropical areas wherePlasmodium falciparummalaria is endemic, co‐infection with HIV‐1 does not lead to a worsening of malaria, raising questions about the immunological interactions between both infections. Alterations of immune response to malaria during HIV‐1 infection was investigated in the town of Bobo Dioulasso, Burkina Faso. Sixty‐six adults were enrolled, including 37 HIV‐1 positive subjects with<250 CD4+cells/μl and clinical AIDS, and 29 HIV‐1 negative healthy subjects.In vitrolymphocyte proliferation and cytokine (IFN‐γ, IL‐2 and IL‐4) production were assessed in isolated mononuclear cells (PBMC) in presence of PHA, PPD or three malarial antigens: the baculovirus‐expressed protein fromP. falciparumMerozoite Surface Protein‐1, aP. falciparum in vitroculture and a crude schizont extract. Compared with healthy subjects, AIDS patients presented with decreased levels of cell proliferation and of IFN‐γ and IL‐2 production, in response to all antigens except the schizont extract. Similar levels of IL‐4 production were obtained in both groups. Mitogenic stimulation of whole blood cultures was also performed, and revealed similar trends in cytokine production as in PBMC cultures. These results show that some components of the specific human immune responses to falciparum parasites may not be modified during AIDS, in spite of the strong cellular alterations induced by HIV, namely the decreas

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-116.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

American cutaneous leishmaniasis (ACL) presents a spectrum of clinical and immunological manifestations. Since the nature of the cellular response appears to play a fundamental role in determining the characteristics of the immunoglobulin isotype of specific antibody responses, we have compared the relative levels of specific antibodies of the four IgG isotypes againstLeishmaniain sera from patients with different clinical manifestations of ACL. Using a specific antibody capture assay, significant levels of antibodies of the IgG1, 2 and 3 isotypes were detected in localized cutaneous leishmaniasis (LCL); the average level of IgG4 antibodies was low and they were not detected in 10/20 sera. Sera from muco‐cutaneous leishmaniasis (MCL) gave a comparatively strong IgG1 response. Sera from diffuse cutaneous leishmaniasis (DCL), the rare form characterized by antigen‐specific anergy of cell‐mediated immunity, showed highly significant levels of IgG4 antibodies compared to antibody levels of this isotype in the other groups; IgG1 and IgG2 levels were also elevated. Based on other studies of the relationship between the IgG isotype response and cell‐mediated immunity, these results confirm a Th1‐like CD4+T cell response in LCL and MCL and a significant Th2‐like resp

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-113.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

Immunoblotting andin vitrooncosphere‐killing were used to identify a putative protective molecule inEchinococcus granulosusmature oncospheres. A range of sera from sheep that had been shown to be protected againstE. granulosus, and from those that were not, were tested. The sera used were obtained from sheep hyperimmunized withE. granulosusoncospheres, or immunized with oncosphere non‐denatured extract, with immature oncosphere extract or with denatured extracts of oncospheres. Results indicated the involvement of native antigens of 23, 25, 30, 34 and 40 kDa in the protective response toE. granulosusinfection. The rapid appearance of antibodies to the 23, 25 kDa antigens, their association with early onset of protection andin vitrooncosphere lysis by affinity‐purified antibodies obtained from these fractions, indicated that these antigens contained protective epitopes. Final confirmation was provided by immunization of sheep with fractions prepared by preparative SDS/PAGE, and challenge infection. Only the fraction containing the 23 and 25 kDa molecules was able to stimulate protection. Antisera against this pair of molecules should provide a useful probe for screening anE. granulosusoncosphere cDNA library to identify clones expressing protectiv

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-114.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

The sequence of events involved in effector focus formation around challenge schistosomula in the lungs of mice vaccinated with radiation‐attenuated cercariae of Schistosoma mansoni has been characterized following intravenous administration of lung stage larvae. Histopathological analysis of the lungs of vaccinated animals revealed that infiltrating cells were present around larvae within 24 h. The main increment in cell recruitment occurred between 2 and 4 days, with foci reaching maximal diameter on day 8. No additional infiltration of the airways was detected by bronchoalveolar sampling before day 4 when the maximum number of cells, predominantly lymphocytes, was recovered. In contrast, responses in challenge control animals were relatively slight prior to day 12. IFNγ was the major cytokine in airway cultures from vaccinated mice, the greatest increment in production coinciding with peak cell recruitment. A similar pattern of IFNγ mRNA expression was observed in whole lung extracts, highlighting the dominance of Th1 responses in the effector mechanism. The slow start to focus formation may be due to the need for antigen, released by the intravascular parasite, to be translocated across the endothelium, processed by accessory cells and presented to the helper T cells which orchestrate the effector mechanism. The delay is of the same order as the period of development which the parasite must undergo in the lung, to facilitate further migration. This similarity in the timing may explain why some larvae are able to avoid the consequences of the pulmonary effector res

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-115.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY

摘要:

In the present study we have investigated and comparedin vitrothe specific complement (C) activating activity of three metacestode preparations ofEchinococcus granulosus. Extracts from hydatid cyst fluid (HCF‐ext), protoscoleces (PSC‐ext) and hydatid cyst membrane (HCM‐ext) activated human C producing C3 conversion and generating the C5b6 complex and the terminal C complex (TCC). HCM‐ext showed much lower C activating activity than PSC‐ext and HCF‐ext. Moreover, its ability to generate C5b6 and TCC was lower than its ability to convert C3. On the other hand, PSC‐ext and HCF‐ext proved to be good C activators when their specific C activating activities were compared with that of inulin. However, PSC‐ext produced lower levels of TCC than those produced by HCF‐ext, in spite of the fact that both produced practically the same levels of C3d and C5b6. These results may be consistent with the existence of several mechanisms of C modulation involved in the defence of the parasite ag

ISSN:0141-9838    

DOI:10.1046/j.1365-3024.1996.d01-112.x

出版商:Blackwell Science Ltd    

年代:1996

数据来源: WILEY