摘要:

SummaryThe difficulty of transfecting primary macrophages and macrophage ceil lines has meant that relatively few studies on regulation of gene expression have been performed in these cells. This study has optimized an electroporation procedure for the macrophage cell line RAW 264, but shows that introduction of DNA into the cytoplasm of primary macrophages by electroporation is toxic to the cells. It is proposed that this cell death may have a physiological role in defence against certain viral infections which result in accumulation of cytoplasmic DNA. RAW 264 cells were efficiently transfected by electroporation, but electroporated bone marrow derived macrophages (BMM) showed large scale cell death over a period of 12 h. Electroporation without DNA was not toxic and DNase treatment of samples before transfection prevented cell death. The toxicity of DNA was concentration‐dependent and sequence independent. Synthetic, genomic and plasmid DNA all caused cell death. This sensitivity to DNA seems to be distinct from the antiviral state induced by double‐stranded RNA and may be part of an uncharacterized viral defence system.

ISSN:0004-945X    

DOI:10.1038/icb.1993.8

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryPrevious studies established that the high density (resting) natural killer (NK) cell subset (R‐NK) of peripheral blood NK cells is unresponsive to interleuk:in‐2 (IL‐2) but can be induced to proliferate when cultured with γ‐irradiated malignant melanoma (MM‐170) cells or mitomycin‐C treated activated T cells in the presence of an IL‐2 conditioned medium (IL‐2‐CM). This study has examined additional requirements of this activation process. The induction of proliferation was dependent on cell to cell contact with metabolically active stimulator cells, although no evidence was obtained that stimulation was effected by soluble factors produced by the stimulator cells. Compared with IL‐2‐CM, rIL‐2 was an inefficient costimulator for the induction of NK cell proliferation, suggesting that factors in IL 2‐CM were required in addition to IL‐2, but rIL‐2 was as efficient as IL‐2‐CM in maintaining the proliferation of activated NK cells. Under optimum culture conditions, NK growth of up to 3200‐fold occurred during a proliferation cycle of 18 days. Phenotypic analysis of the culture‐generated quiescent NK cells revealed novel heterogeneity in CD 16 (FcγRIII) and CD56 (N‐CAM) expression. Some NK cells lacked expression of both CD16 and CD56 (as identified using currently available monoclonal antibodies), while other NK cells showed differential CD 16 epitope expression. Since quiescent NK cells can be obtained in large numbers and high purity, they will be a convenient source of NK cells to study the molecular processes involved in initiating NK cell proliferation.

ISSN:0004-945X    

DOI:10.1038/icb.1993.9

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryThe endogenous and lipopolysaccharide stimulated interleukin (IL)‐1β productionin vitroby peritoneal monocytes/macrophages from patients on continuous ambulatory peritoneal dialysis (CAPD) was examined during episodes of infection and inflammation. Measurement of immunoreactive IL‐1β and bioactive IL‐1 in both supernatants and cell lysates after culture for 18 h revealed that these cells secreted a significantly lower proportion of total IL‐1 than that measured for elutriated blood monocytes. For the inflammatory peritoneal cells, the proportion of total IL‐1β that was cell‐associated resembled that reported for more differentiated pulmonary alveolar macrophages and for adherent monocytes cultured for 18 h prior to stimulation. A similar reduced ability to secrete IL‐1β was detected for unfractionated peritoneal cells from CAPD patients without peritonitis upon direct comparison with the IL‐1β production by blood mononuclear cells from the same patients. These results suggested that at a time when a pro‐inflammatory response by extravasated host monocytes/macrophages was required by CAPD patients with peritonitis, only a minor proportion of total IL‐1β would be available extracellularly. This study highlights the rapidity with which extravasated monocytes lose their ability to secrete IL‐lβ and raises the possibility that an important site of utilization of IL‐1βin vivomay be intracellular in its location.

ISSN:0004-945X    

DOI:10.1038/icb.1993.10

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryBispecific antibody (BSAb) consisting of anti‐CD3 plus anti‐c‐cerbB‐2 Fab fragments for the application to adoptive tumour immunotherapy was prepared. This bifunctional hetero‐F(ab′)2antibody reacted with both human CD3+T cells andc‐erbB‐2 positive human tumour cells. Human CD8+T cells activated with immobilized anti‐CD3 plus interleukin 2 showed marginal cytotoxicity against tumour cells. However, addition of the prepared BSAb into the culture resulted in a marked augmentation of the cytotoxicity by the activated CD8+T cells in a dose‐dependent manner. The enhanced cytotoxicity of CD8+T cells in the presence of BSAb was specific forc‐erbB‐2 positive tumour cells. Moreover, it was demonstrated that anti‐CD3 × anti‐c‐erbB‐2 BSAb was also effective for the specific targeting of various kinds ofin vitro‐activated antitumour effector cells such as lymphokine‐activated killer cells, CD4+helper/killer cells, γδ T cells and activated tumour‐infiltrating CD8+T cells. These results indicated that BSAb consisted of anti‐CD3 and anti‐c‐erbB‐2 will become a useful tool for the adoptive tumour immunotherapy of human cancer expressingc‐erbB‐2 oncogene products.

ISSN:0004-945X    

DOI:10.1038/icb.1993.11

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryThe antifibrin DD‐3B6/22 monoclonal antibody Fab′ fragment, a murine immunoglobulin, IgG3, has been labelled with technetium‐99 m (99mTc) via a transchelation reaction, to specific activity in excess of 30 mCi/mg protein. The radio labelling of Fab′ was dependent on time, temperature, pH, antibody concentrations and nature of intermediary transchelation complex used. The resultant radio conjugate was stablein vitroandin vivo.Blood clearance of99mTc‐Fab′ in rat followed two compartment kinetics with the half time of the fast phase being 0.5 h. The main route of excretion was via the kidneys with little uptake indicated by other tissues. The results suggest that the inherent specificity of the antibody, small molecular size, rapid plasma clearance, high specific radioactivity, together with the physical properties of the99mTc label, combine to make this labeled monoclonal antibody (MoAb), potentially suitable as a radiopharmaceutical for the scintigraphic detection of thrombi in humans.

ISSN:0004-945X    

DOI:10.1038/icb.1993.12

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummarySomatostatin inhibitsin vitrolymphocyte proliferative responses from a variety of species including human, mouse and rat. The immunoinhibitory effects of somatostatin are thought to involve binding to specific cell surface somatostatin receptors on immunocompetent cells. This report describes anin vivoimmuno inhibitory effect of somatostatin on the rat pophteal lymph node lymphocyte primary antibody response to sheep red blood cell (SRBC) stimulation. Infusion of somatostatin immediately following SRBC injection into the hind feet of rats had a dose‐related inhibitory effect. At the highest concentration used, 10 μmol/L, the level of inhibition was similar to that previously described following neonatal capsaicin treatment of rats. This suggests that neonatal capsaicin treatment may lead to decreased primary antibody responses to SRBC by a selective effect on tachykinin containing nerves and a lesser effect on somatostatin containing nerves. The immuno inhibitory effect of somatostatin was reversed by co infusion of neurokinin A but not substance P, both of which have been shown to stimulate this response. This suggests the possibility that multiple tachykinin receptors are involved in the modulation of the SRBC primary antibody responsein vivoThese results present evidence for anin vivoimmunomodulatory role of somatostatin.

ISSN:0004-945X    

DOI:10.1038/icb.1993.13

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryA model for cell movement is presented. It is suggested that cells do not migrate on collagen using their VLA (very late antigen) integrins that bind this extra cellular matrix protein. Rather, the cells utilize αv integrins to bind endogenously produced fibronectin, which binds to the underlying collagen. It is envisaged that cells proceed by a process of engagement and disengagement of αv integrins to the extracellular matrix, somewhat analogous to the motion of a monkey climbing a tree. Secretion of isoforms of the adhesion modulator, thrombospondin, regulates disengagement of the integrin from its ligand in migrating cells. The integrin disengagement signal is mediated by thrombospondin cross‐linking the αv integnn to an integrin accessory molecule and thus activating protein kinases. The cross‐linked receptor complex undergoes recycling back along actin stress fibres, guided by the integrin β‐subunit. After endocytosis and protein sorting the αv integrin is transported back to the leading edge off migrating cells in vesicles guided by the tubulin‐binding capabilities of an integrin accessory molecule. Direct attachment to collagen required for processes, such as matrix contraction, is mediated by VLA integrins which displace αv integrins from points of attachment during integrin recycling, possibly through an αvβ1, intermediary receptor.

ISSN:0004-945X    

DOI:10.1038/icb.1993.14

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryA hypothesis is proposed asking why enzyme neutralization is not an effective host‐response to a parasite despite the fact that some parasite housekeeping enzymes are highly immunogenic. It is hypothesized that although the structural domain can be immunogenic, the active sites of the parasite enzyme molecules have converged evolutionarily to resemble the functional part (active sites) of host's enzyme molecules, by structural modification/rearrangement (amino acid substitution/polypeptide chain folding) with the effect: (i) of functional adaptation to the host environment; and (ii) to escape detection of active sites by the host as non‐self, allowing the parasite to be exposed to antiparasite enzyme antibodies, without deleterious effects on the parasite.

ISSN:0004-945X    

DOI:10.1038/icb.1993.15

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryThe utilization of the β2‐microglobulin (B2m) exchange assay allowed for the association of H 2Ldwith human B2m. Upon association with H‐2Ld, human B2m induces structural alterations in H‐2Ldthat appear dependent upon xenogeneic B2m amino acid sequence variability. In this regard, xenogeneic B2m exchange is used as a tool to induce structural alterations in class I as a means of analysing the structural‐functional relationship of B2m/class I association. Incorporating H‐2Ldsite‐directed mutants into the experimental approach provided strong evidence that B2m makes indirect contact with discrete class I specific amino acid positions located in the helical region of the α1domain.

ISSN:0004-945X    

DOI:10.1038/icb.1993.16

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

Book reviewed in this articleLIVING RESOURCES FOR BIOTECHNOLOGY. ANIMAL CELLS Edited by A. Doyle, R. Hay and B. E. Kirsop.CONTROL OF VIRUS DISEASES Edited by N. J. Dimmock, P. D. Griffiths and C. R. Madeley.MUIR'S TEXTBOOK OF PATHOLOGY, 13th edn Edited by R. N. M. MacSween and K. Whaley.

ISSN:0004-945X    

DOI:10.1038/icb.1993.17

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY