摘要:

SummaryRecombinant DNA techniques were used to clone, construct and express the bifunctional molecule FV/IL‐2. The FV/IL‐2 is a single‐chain 37kDa fusion protein expressed inEscherichia coliunder control of the strong T7 bacteriophage promoter in the expression vector pT7‐7‐FV‐lL‐2. The fused gene fragment FV‐IL‐2 contains a single‐chain anti‐TAG72 FV gene fragment and the human recombinant cDNA fragment of the IL‐2 molecule. The renatured soluble form of FV/IL‐2 was purified fromE. coliinclusion bodies using hydroxylapatite chromatography. The yield of this fusion protein was estimated at 2.0 mg/L. Our data showed that the FV/IL‐2 molecule retained the TAG72 antigen‐binding specificity and the IL‐2 activity as measured in the standard T cell proliferation as well as cytotoxicity assays. Therefore, it may prove to be useful in targeting the biological effect of lL‐2 to tumour cells and stimulating its immune destruction.

ISSN:0004-945X    

DOI:10.1038/icb.1994.42

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryThe role ofPlasmodium falciparumand activated blood monocytes in bringing about erythrocyte membrane lipid peroxidation and in altering the enzyme activity associated with Ca2+and K+efflux was studied. An attempt was made to investigate the role of parasite and monocyte‐mediated reactive oxygen species (ROS) in inhibiting Ca2+‐Mg2+ATPase and Na+‐K+ATPase in order to find out the cause of reported high intra‐erythrocytic calcium and depleted potassium levels in parasitized erythrocytes (PRBC). The PRBC showed enhanced lipid peroxidation as indicated by increased malonyldialdehyde (MDA) formation which coincided with the maturity of the parasite. This was further enhanced following exposure of PRBC to activated blood monocytes. The Ca2+‐Mg2+ATPase activity was decreased as the parasite matured and was further hampered significantly in mature parasite‐infected red cells exposed to activated blood monocytes. There was a good negative correlation between MDA formation and Ca2+‐efflux from red blood cells suggesting the negative influence of ROS on Ca2+‐efflux. The Na+‐K+ATPase activity did not reveal any significant change, both during parasite maturation as well as upon exposure to ROS from activated monocytes. We therefore suggest that inhibition of Ca2+‐efflux and the resulting increased cytosolic Ca+in PRBC might have a role in structural and functional abnormalities of red blood cell, thus enhancing the red cell loss duringP. falciparuminfection.

ISSN:0004-945X    

DOI:10.1038/icb.1994.43

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryHuman multinegative (CD3−4−8−19−; MN) thymocytes proliferate optimally in response to anti‐CD2 plus anti‐CD28 mAb plus PMA or IL‐7. The role of CD45 was assessed by the addition of mAb to a CD45 common determinant, or to CD45RA. MN thymocytes are unresponsive to anti‐CD2 mAb. Co‐stimulation with anti‐CD45RA generated 1.6–5.7‐fold enhancement of a proliferative response, with maximal enhancement by cross‐linkage of CD45RA molecules. The response to anti‐CD2/28 mAb was reproducibly enhanced only by immobilized anti‐CD45RA. Cross‐linking of CD45RA and CD28 through the use of heteroconjugates of mAb did not enhance the co‐stimulation by CD45RA. The most marked enhancement by anti‐CD45RA occurred in suboptimal activation conditions. In contrast, the response to anti‐CD2 or anti‐CD2/28 was inhibited by mAb to CD45 common determinants (anti‐CD45) in the presence or absence of PMA or IL‐7, with the most profound inhibition (6–8‐fold) detected in optimal proliferative conditions. Cross‐linking of CD45 and CD28 through heteroconjugates of mAb was required as soluble anti‐CD45 or immobilized anti‐CD45 were unable to mediate inhibition. This inhibitory effect of (anti‐CD45 × 28) was specific to MN thymocytes as no inhibition was detectable when peripheral blood T cells were treated with anti‐CD2/28 and the same heteroconjugate. The differential effects of anti‐CD45 and anti‐CD45RA may reflect either CD45 heterogeneity on MN thymocytes, or the physical modulation of a single CD45 molecules by interactions at different epitopes, and the avidity of the relevant CD45 mAb for thymocyte CD45 isoforms may play a role. We conclude that the molecular associations between signal transduction molecules on progenitor thymocytes differ significantly from those assembled on peripheral blood T cells.

ISSN:0004-945X    

DOI:10.1038/icb.1994.44

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryIn a serum‐free medium addition of insulin‐like growth factor‐1 (IGF‐1) consistently enhanced lymphocyte proliferation response to PHA in a dose‐dependent fashion. This effect was produced by an acceleration in the expression of clone expansion and not in the number of proliferating cells. This was documented by kinetics data obtained from the first proliferation round of PHA‐stimulated lymphocytes, in which addition of IGE‐1 reduced G1‐phase length, without changing Go‐phase, S‐phase or cloned size. The data were confirmed in 10‐day culture of stimulated lymphocytes where IGF‐1 only accelerated cell proliferation without modifying the area enclosed by the proliferation curve. As IGF‐1 is under the control of growth hormone, our results suggest that some of the immunoregulation effects ascribed to growth hormonein vivocould be produced by IGF‐1.

ISSN:0004-945X    

DOI:10.1038/icb.1994.45

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryHuman breast milk has important immunoprotective and immunosuppressive functions for an infant. The purpose of this study was to extend the phenotype of milk cells and to measure soluble T cell receptor levels and cytokines in milk, and to compare these with neonatal and adult blood. Milk T cells had a more equivalent CD4: CD8 ratio than blood; milk CD4 T cells mainly expressed the CD45RO (antigen primed/memory) phenotype; milk CD8 cells had an equivalent CDllb:CD28 suppressor; cytotoxic phenotype; and milk T cells had 2‐3‐fold higher percentages of activated CD4 IL‐2R and CD8 HML‐1 or CD8 VLA‐1 cells than blood. Soluble IL‐2R, CD4 and CD8 concentrations were lower in milk than adult blood, although relatively increased when compared to the lower T cell concentration in milk. Breast milk contained high levels of IFN‐γ but low levels of other measured cytokines compared to blood. These distinct differences of T cells and their soluble products are likely to influence an infant's immune system.

ISSN:0004-945X    

DOI:10.1038/icb.1994.46

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryAsPneumocystis cariniicysts cannot be cultivated for enumeration of colony forming cells, two alternative approaches to measuring killingof P. cariniiby mouse peritoneal cells were investigated. The cells tested were either normal resident peritoneal cells, or cells which were elicited by intraperitoneal injection of the bacteriumListeria monocytogenes.The latter population showed enhanced antibacterial activity againstListeriaorganisms and enhanced production of H2O2in the presence ofP. carinii, cysts from immunosuppressed rats. To assess killing ofP. carinii, cysts were mixed with peritoneal cells at a ratio of 10:1, and after intervals of incuabation the peritoneal cells were lysed by saponin treatment. The viability of the cysts was assessed by staining with vital dyes or by uptake of tritiated uridine over 7 h incubation. Viability of cysts was unaffected by saponin treatment, and there was agreement between the two techniques that the elicited peritoneal cells killed approximately twice the number of cysts over a 20 h incubation period compared to normal resident peritoneal cells.

ISSN:0004-945X    

DOI:10.1038/icb.1994.47

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummarySeveral accessory molecules were shown to play important roles in T cell functions and be in dose proximity to the T cell receptor (TcRyCD3). The L‐selectin molecule (Leu8, LAM 1‐1, LECAM1) also plays an important role in lymphocyte homing and proliferation. We were interested in determining the proximity of this molecule to the TcR/CD3 complex on live peripheral human T cells. Using a fluorescence energy transfer method, designed to study individual cells, we could show that L‐selectin is within 170 Å of the TcR/CD3 complex. Monoclonal antibody directed against the LAMl‐l (Leu8) epitope of the L‐selectin molecule suppressed the mitogenic activity of antibodies specific for various CD3 epitopesin vitro.Intracellular Ca2+mobilization obtained with wt31 followed by cross‐linking antibody or with anti‐CD3 was not influenced by anti‐Leu8 antibody. Also antibody directed against the LAMl‐1 epitope did not influence the binding of the mitogenic antibodies, as shown by fluorescence‐based flow cytometry. Therefore, we suggest that binding of TcR/CD3 bound mitogenic antibodies to accessory cell Fc receptors may be hindered by antibodies bound to the close proximity L‐selectin molecules.

ISSN:0004-945X    

DOI:10.1038/icb.1994.48

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryA humoral recognition molecule that is homologous to the mammalian complement components C3, C4 and C5 has recently been identified in the Pacific hagfish,Eptatretus stouti.One function of this complement‐like protein (CLP) is to opsonize foreign material for phagocytosis by hagfish leucocytes. Here, we demonstrate that CLP's opsonic activity can be abrogated by pre‐incubating phagocytes with an anti‐hagfish leucocyte mAb (IBI). Moreover, antigen‐activated CLP can block the binding of the IBI antibody to hagfish leucocytes. Flow cytometry and immunoprecipitation indicate that IBI recognizes a 105 kDa cell‐surface, monomeric protein that is expressed exclusively on phagocytic hagfish leucocytes. It is concluded that this 105 kDa protein represents the cell surface receptor by which CLP mediates the phagocytosis of opsonized targets.

ISSN:0004-945X    

DOI:10.1038/icb.1994.49

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryImmunization of 48 cattle with somatic antigen extracts of the nodular worm,Oesophagostomum radiatum, reduced faecal egg counts (FEC) by 51% and worm burden by 47%. The antibody titre of each animal was correlated to both worm burden (

ISSN:0004-945X    

DOI:10.1038/icb.1994.50

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY

摘要:

SummaryCo‐selection is a term used to denote the mutual positive selection of individual members from within two diverse populations, such that selection of members within one population is dependent on interaction with (recognition of) one or more member(s) within the other population. Co‐selection is a recurring theme of the idiotypic network model that my colleagues and I have developed. This paper discusses the role that co‐selection plays in basic symmetrical network theory and in a network model that resolves the I‐J paradox. It proposes that co‐selection of helper T cells and HIV variants plays a role in the pathogenesis of AIDS. The AIDS model involves a role for the T cell receptor in the infection of T cells. Finally, a way in which a co‐selection process may potentially be used in the prevention and therapy of harmful forms of immunity is described.

ISSN:0004-945X    

DOI:10.1038/icb.1994.51

出版商:Blackwell Publishing Ltd    

年代:2017

数据来源: WILEY