ISSN:0004-945X    

DOI:10.1038/icb.1996.91

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.The primary cytotoxicity ofStaphylococcalenterotoxin B (SEB)‐stimulated PBMC and separated CD8+and CD4+T cells against Burkitt's lymphoma target cells has been characterized by applying two stimulation protocols. In the bulk protocol, the PBMC were stimulated with 100 ng/mL SEB for 3 days before separation to CD4+and CD8+T subsets. In the direct protocol, the separated CD4+and CD8+T cells were stimulated with 100 ng SEB preabsorbed to mitomycin C (MMC)‐treated APC. Comparison of the results of the two different protocols revealed the following differences: (i) PBMC in the direct protocol provided greater cytolytic activity than in the bulk protocol; and (ii) the CD4+T cells acquired cytotoxicity only in the direct protocol. Unexpectedly, the superantigen‐dependent cellular cytotoxicity (SDCC) of SEB‐stimulated cells was not dominant compared with the basal cytotoxicity. The classical NK target, K‐562 was also sensitive to SEB‐augmented cytotoxicity. The parallel stimulation with IL‐2 and SEB caused a similar extent of cytotoxicity enhancement against both types of target cells. However, the cyclosporin A (CSA) inhibited only the SEB‐induced cytotoxicity. The results suggest that SEB‐induced PBMC acquire mainly a LAK‐like cytotoxicity, as a consequence of newly produced lymphokines. This observation might propose a different approach in pathological studies.

ISSN:0004-945X    

DOI:10.1038/icb.1996.80

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.The mucosal addressin cell adhesion molecule‐1 (MAdCAM‐1). expressed selectively on high endothelial venules (HEV) and lamina propria venules, directs lymphocyte traffic by binding the lymphocyte Peyer's patch adhesion molecule‐1 (LPAM‐1, α4β7). Full‐length DNA encoding human MAdCAM‐1 was obtained by combining sequences from an expressed sequence tag (EST) identified in an early stage human brain cDNA library, a polymerase chain reaction‐derived clone, and a MAdCAM‐1 genomic clone. The deduced amino acid sequence revealed an 18 amino acid signal peptide, two N‐terminal immunoglobulin (Ig)‐like domains conserved (59–65%) in sequence with those of the mouse homologue, an 86 amino acid mucin‐like region rich in serine‐threonine residues, a 20 amino acid transmembrane domain and a 43 amino acid charged cytoplasmic domain. No counterpart to the third IgA‐like domain of mouse MAdCAM‐1 was present; however, the serine‐threonine‐rich mucin domain was extended as two distinguishable major and minor mucin regions unrelated to the mouse mucin domain. The major domain is formed from six tandem repeats of an eight amino acid sequence having the MUC‐2‐related consensus DTTSPEP/SP. Human MAdCAM‐1 mRNA transcripts were restricted to small intestine, colon, spleen, pancreas and brain. Alternatively spliced MAdCAM‐1 variants were identified that lack parts of the second Ig domain and all or part of the major mucin domain, indicating that the function of this vascular addressin is regulated by extensive modifications to its multi‐domain structure.

ISSN:0004-945X    

DOI:10.1038/icb.1996.81

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.Infusion of LPS or nematode larvae into the mammary glands of sheep induces recruitment of neutrophils or eosinophils respectively. While neutrophil recruitment required only a single infusion of LPS, repeated infusions of parasite larvae were required to induce significant eosinophil migration into the lumen of the glands. Eosinophil recruitment was accompanied by a distinct population of lymphocytes consisting mainly of activated (MHC class II and CD25+) T cells. L‐selectin was expressed at reduced levels on both neutrophils and eosinophils collected from the mammary gland compared with cells present in the blood of the same sheep. In addition, VLA‐4 and β1‐integrin were down‐regulated or negative in mammary eosinophils compared with strong expression in the blood while neutrophils were negative for these markers in both mammary washes and blood. Eosinophils in blood and mammary glands were negative for MHC class II, CD25 and CD4. Mast cells and lymphocyte aggregates were present in the tissue of glands chronically stimulated with parasite larvae while eosinophils were only present if the gland had been recently stimulated.These studies show that detailedin vivoanalysis of leucocyte migration can be easily performed in the sheep mammary infusion model which allows non‐invasive and repeated sampling of inflammatory cells before and after tissue migration.

ISSN:0004-945X    

DOI:10.1038/icb.1996.82

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.Human adenoviruses have provided valuable insights into virus‐host interactions at the clinical and experimental levels. In addition to the medical importance of adenoviruses in acute infections and the ability of the virus to persist in the host, adenovirus‐based recombinants are being developed as potential vaccine vectors. It is now clear that adenoviruses employ various strategies to modulate the innate and the adaptive host immune defences. Adenovirus genome‐coded products that interact with the immune response of the host have been identified, and to a large extent the molecular mechanisms of their functions have been revealed. Such knowledge will no doubt influence our approach to the areas of viral pathogenesis, vaccine development and immune modulation for disease management.

ISSN:0004-945X    

DOI:10.1038/icb.1996.83

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.Herpesviruses have acquired a variety of different mechanisms to avoid the damaging effects of host immunity. Frequently, these viruses subvert normal immune regulatory functions utilized by the host. The focus of this review is upon herpesvirus genes encoding known or potential immunomodulatory proteins. Areas covered include inhibition of complement and antibody function, herpesvirus‐encoded homologues of cytokines and chemokine receptors, and potential disruption of cellular recognition of virally infected targets.

ISSN:0004-945X    

DOI:10.1038/icb.1996.84

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.Herpesviruses are an ancient, ubiquitous family of DNA viruses, most of which share a lifestyle of latently or persistently infecting a young host, and spreading to infect a new host a generation later. Most herpesviruses interfere with antigen presentation via the MHC class I‐restricted pathway of antigen presentation, suggesting that impairment of the cytotoxic T lymphocyte response is necessary for the maintenance of this lifestyle. The diverse molecular mechanisms that have so far been discovered employed by Epstein‐Barr virus, herpes simplex viruses, and human and murine cytomegaloviruses are described in this review.

ISSN:0004-945X    

DOI:10.1038/icb.1996.85

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.Apoptosis is a form of cell death distinct from necrosis which plays an important role in processes such as homoeostasis and the elimination of damaged cells. It can be triggered by a variety of stimuli including DNA damage and cytotoxic T lymphocyte activity,1both of which may be induced in the course of a viral infection. Initially, induction of apoptosis may occur through pathways which have also been shown to be activated on disturbance of the cell cycle or damage to cellular DNA.2At later time points during the course of infection, apoptosis can also be triggered by cytokines and immune effector cells.1Apoptosis of the host cell before the completion of the viral replication cycle may limit the number of progeny and the spread of infection. The importance of apoptosis as an antiviral defence is illustrated by the presence of multiple pathways for apoptosis induction and inhibition in both the host and virus. In this review, the inhibition of apoptosis is described in adenovirus and poxvirus infection. These examples illustrate two of the divergent paths by which viruses may avoid the apoptotic response.

ISSN:0004-945X    

DOI:10.1038/icb.1996.86

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.Poxviruses are experts at manipulating and evading the host's immune response. They have acquired a number of open reading frames which specifically confer direct anti‐immune properties, either by mimicking cytokine receptors and growth factors or by disarming cytokine regulatory cascades. The Myxoma T2 protein (M‐T2), a TNF receptor homologue is secreted from virus infected cells and can bind TNF‐α with high affinity, and thereby inhibit TNF‐α‐mediated cytotoxicity. M‐T2 also acts to inhibit virus‐induced lymphocyte apoptosis by an as yet undefined mechanism. As such, T2 constitutes a significant virulence factor for poxviruses, influencing the outcome of infection, bothin vitroandin vivo.

ISSN:0004-945X    

DOI:10.1038/icb.1996.87

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Summary.Plasmodium falciparummalaria is responsible for 2 million deaths each year. Even in endemic regions, immunity to malaria builds slowly and is rarely complete. Strategies such as antigenic variation and antigenic diversity are critical to a parasite's ability to evade the host immune response and infect previously exposed individuals. In this short review, the phenomenon of antigenic variation is discussed in relation to immune evasion and its impact on parasite pathogenesis. Recent advances in the understanding of the underlying molecular mechanisms of antigenic variation are examined and questions posed for future research.

ISSN:0004-945X    

DOI:10.1038/icb.1996.88

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY