ISSN:0004-945X    

DOI:10.1038/icb.1995.93

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryProlactin (PRL), an endocrine hormone from the anterior pituitary, is also synthesized and secreted by activated immunocytes, mostly T cells and thymocytes.In vitroPRL acts as an autocrine or paracrine growth factor which regulates the proliferation of previously stimulated immunocompetent cells. PRL acts through its specific cell surface receptors expressed on different immunocytes including T cells, B cells, monocytes, NK cells and neutrophils.In vivothe immunoregulatory role of PRL is still the subject of intense investigation, especially in the conditions of stress and reproduction. The conflicting results suggest that PRL concentration, sex hormones and some other factors influence the immunomodulatory role of PRL.

ISSN:0004-945X    

DOI:10.1038/icb.1995.77

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryEfforts to design effective mucosal vaccines have been hampered by an incomplete understanding of factors controlling the development of mucosal immunity. It is now clear, however, that T cell‐derived cytokines play a major role. Recent developments in ‘gene knockout’ technology have allowed the generation of strains of mice in which particular genes have been inactivated. The availability of mice rendered deficient for production of Th2 cytokines has facilitated studies of the induction and development of mucosal immune responses in the absence of these factors. We have used several genetic approaches, including cytokine‐deficient mice and recombinant vectors constructed to express genes for a range of different cytokines, to demonstrate the importance of these factors in the mucosa. Such genetic approaches appear to represent powerful tools forin vivostudies of the influence of cytokines in mucosal immunoregulation.

ISSN:0004-945X    

DOI:10.1038/icb.1995.78

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryEpstein‐Barr virus achieves its ubiquitous and uniform epidemiological distribution by a dual strategy of latency to guarantee lifelong persistence and intermittent replication to guarantee transmission. These two functions appear to dictate residence in different cell types: latency in B lymphocytes and replication in epithelial cells. Both of these cell compartments are potential sites for FBV‐associated malignancies.

ISSN:0004-945X    

DOI:10.1038/icb.1995.79

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryPorcidin P1, an antimicrobial peptide purified from the granules of porcine polymorphonuclear neutrophils (PMN) using ultrafillration and reverse phase high performance liquid chromatography (RPHPLC), was covalently conjugated to BSA and used to generate monospecific polyclonal ascites. Antibodies raised against porcidin P1 were covalently coupled to an Affi‐gel Hz affinity column and used for immunoaffinity chromatography of peptides from porcine PMN cell extract. Eleven immunorelated peptides were eluted from the column from neutrophil cell extracts and purified to homogeneity by HPLC. The molecular weights of the immunorelated peptides were determined by mass spectral analysis and ranged in size from 1.91 to 10.65 kDa. Of the II immunorelated peptides which were bound to the affinity column, only six peptides were recognized by the anti‐porcidin antibodies after HPLC purification. Three immunoreactive peptides displayed potent antibacterial activity towardsStaphylococcus aureus and Escherichia coli.reducing viability by as much as 99.9% (>3 log reduction in CFU) when 5 μg/mL of each purified peptide was used. The polydonal monospecific antibodies also reacted with proteins from ovine and human PMN, illustrating possible structural relationships between small antibacterial peptides from the different species.

ISSN:0004-945X    

DOI:10.1038/icb.1995.80

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryLymphocyte proliferation is guided by receptor‐mediated signal transduction pathways that dictate the immunological response/clonality of that cell. We have previously reported that NZB‐derived malignant B‐1 cells, which serve as a murine model for human chronic lymphocytic leukaemia, demonstrate altered expression of surface IgM and CD45 signalling molecules, and a failure to proliferate following membrane IgM stimulation. To examine receptor‐mediated cytosolic calcium (Ca1) signalling in B cell leukaemia, we studied IgM‐induced Ca, responses in malignant B‐1 cells and B cells from non‐leukaemic mice. Basal Ca1was slightly lower in malignant B‐l cells than in non‐leukaemic cells. Anti‐IgM stimulation induced a sustained increase in Ca1to levels 1.3‐fold greater than basal Ca1in conventional B cells. In contrast, leukaemic B‐1 cells demonstrated a sharp but transient rise in Ca1followed by a gradual increase to levels 2.3‐fold greater than basal [Ca]1Ca influx from extracellular sources contributed to the early and late Ca1signal in both sets of cells. Pre‐incubation (2–30 min) with anti‐CD45 had no effect on basal Ca, or the anti‐IgM Ca1signal in B cells, but reduced the Ca1transient in malignant B‐1 cells. Additional experiments characterized the effects of phosphorylation/dephosphorylation events on the Ca1profile following anti‐IgM stimulation. Protein tyrosine kinase inhibitors decreased the anti‐IgM‐induced Ca1transient in malignant B‐1 cells by 80%, but only moderately affected 40% the Ca1response in non‐leukaemic B cells. Protein tyrosine phosphatase inhibitors and protein kinase C (PKC) activators attenuated the Ca1response to the same degree in normal and leukaemic B cells. These results show that Ca1signalling differs widely between non‐malignant B cells and malignant B‐1 cells, and that tyrosine phosphorylation and CD45 modulation of IgM signalling are involved in the altered Ca1responses in malignant B‐1 cells.

ISSN:0004-945X    

DOI:10.1038/icb.1995.81

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryC‐reactive protein (CRP) is a prototypic acute phase reactant in humans and rabbits whose serum concentration can increase up to 1000‐fold following an acute inflammatory stimulus. CRP binds to many phosphate ester‐containing compounds including phosphorylcholine, nucleotides, chromatin and snRNP. To examine thein vivofunction of this protein, we produced transgenic mice capable of significant CRP synthesis. In contrast to most other vertebrates, mice synthesize CRP in only trace amounts. The transgenic animals express rabbit CRP from either the phosphoenolpyruvate carboxykinase promoter (PEPCK‐CRP) or the mouse metallothionein I promoter (MT‐CRP). Manipulating the diet in one of the PEPCK‐CRP lines led to a rise in serum CRP levels from<5 μg/mL to 100–200 μg/mL over a period of 2 days. The two MT‐CRP lines examined expressed CRP constitutively which could be further elevated 2–4‐fold following an inflammatory stimulus. Transgenic CRP bound phosphonlcholine was pentameric, had a circulating half‐life of 30–60 min and was capable of activating mouse complement when bound to a ligand. We conclude that these transgenic lines express CRP with many of the properties of authentic rabbit CRP, and that the expression of CRP can be controlled to be dependent or independent of the acute phase response.

ISSN:0004-945X    

DOI:10.1038/icb.1995.82

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummarySelective pairwise interactions between a number of CD3 chains and the clonotypic T cell antigen receptor (TCR‐α, ‐β) chains have recently been reported.1What still remains unanswered is the site of interaction between TCR‐β and CD3‐γ chains. To examine the region of interaction between TCR‐β and CD3‐γ chains, a variety of genetically altered TGR‐β and CD3‐γ chains were constructed using recombinant cDNA techniques. Non‐T cells (COS‐7) were transfected with cDNA constructs, metabolically labelled, and immunoprecipitates were analysed for assembly using non‐equilibrium pH gel electrophoresis (NEPHGE)/ SDS‐PAGE. The results demonstrated that assembly between TCR‐β and CD3‐γ chains was localized to their extracellular domain. These findings, when coupled with the information on pairwise interactions and formation of higher order subcomplexes, extend our model of the structure of the TCR complex.

ISSN:0004-945X    

DOI:10.1038/icb.1995.83

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryProtection against infection withMycobacterium tuberculosisis preferentially associated with the development of the T helper 1 subset, IFN‐γ production and a cell‐mediated response, rather than with T helper 2 cells, 4 (IL‐4) and antibody production. The type of APC interacting with T cells responsive to mycobacterial peptides may influence which of these responses predominates. This investigation focuses on the role of dendritic cells (DC) because they are the most potent APC in both primary and recall immune responses. Our results show that splenic DC‐enriched suspensions prepared from C57BL/6 mice and pulsed with either purified protein derivative (PPD) or the immunodominant 19 kDa protein fromM. tuberculosis, can activate antigen‐primed T cellsin vitro, whereas spleen cell suspensions depleted of DC cannot. DC pulsed with PPD or 19 kDa antigen are able to prime naive T cellsin vivo.Supernatants collected from cultures containing T cells from mice injected with PPD‐pulsed DC and then challengedin vitrowith PPD‐pulsed DC were found to contain more IL‐2 and IFN‐γ than those from control mice which received either DC or PPD alone. No such antigen‐specific IFN‐γ response occurred if DC pulsed with 19 kDa were used in place of PPD‐pulsed DC. IL‐4 was not detected in any of the culture supernatants. We conclude that DC can induce production of cytokines associated with a protective immune response when presenting peptides derived from heterogeneous mycobacterial antigens but not when exposed to the single 19 kDa immunodominant protein.

ISSN:0004-945X    

DOI:10.1038/icb.1995.84

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryThe formation of partial complexes in an African green monkey kidney cell line (COS cells) has been used to examine assembly of newly synthesized T cell antigen receptor (TCR) chains. The identification of assembly interactions between multiple subunits and the formation of higher order subcomplexes has led to the development of a model for the hierarchy of subunit assembly leading to a complete TCR. These assembly interactions suggest likely nearest neighbour relationships in the assembling structure and probably reflect the quarternary structure ofthe TCR complex. This may be important when examining the association of other molecules with TCR proteins or when trying to discern structural components involved with signal transduction.

ISSN:0004-945X    

DOI:10.1038/icb.1995.85

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY