摘要:

AbstractUnfractionated as well as small and large human tonsillar B cells were found to differentiate in the presence of recombinant interleukin 2 (IL 2) without requiring anin vitropreactivation signal. These cell suspensions did not contain detectable T cells, monocytes or natural killer cells both at the initiation and the termination of cultures, and did not respond to the T cell‐dependent polyclonal B cell activator pokeweed mitogen. They contained very few Tac antigen‐bearing cells (less than 2.5%) at the beginning and at the termination of the cultures in the absence of IL 2. In the presence of IL 2, only a minimal increase in the number of Tac antigen‐bearing cells was noted. The observed differentiation was not due to the effects of contaminating T cells, since cultures purposely contaminated with up to 5% of T cells did not contain greater amounts of IgM, IgG or IgA than cultures without T cells added back. Furthermore, when T cells were present at a ratio of IT cell per 9 B cells, the production of IgM was decreased. Taken together, these data support the hypothesis that (a) B cell differentiation in response to IL 2 may occur in the absence ofin vitropreactivation, and in this case cannot be related to the expression of Tac antigen on the B cell surface; (b) it is not due to helper effects of very low numbers of T cells which might contaminate the B cell suspensions; and (c) it most likely results from a direct effect of IL 2 on B cells themselves. The data also point out the fact that, in the presence of IL 2, T cells may trigger inhibitory effects on IL2‐induced B cell differentiation rather than provide helper

ISSN:0014-2980    

DOI:10.1002/eji.1830151102

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractThe effect of inhibition of protein synthesis on interferon gamma (IFN‐γ) mRNA induction has been examined in human peripheral blood leukocytes and growing T lymphoblasts. Inhibition of protein synthesis by cycloheximide or puromycin when lymphocytes were stimulated with mitogen alone had little effect on the steady‐state levels of IFN‐γ mRNA induced. Activation of the IFN‐γ gene appears to occur independently of synthesis of protein factors.Synergistic induction of IFN‐γ by mitogen plus the phorbol ester mezerein was at least in part accounted for by increased levels of IFN‐γ mRNA in both fresh lymphocytes and growing lymphoblasts. Inhibition of protein synthesis abolished the synergistic effect on mRNA leading to levels similar to those observed in cells treated with mitogen alone. Synergistic induction is dependent upon synthesis of protein factors either within the cells or produced as soluble mediators; these factors are not simply lymphokines since addition of exogenous factors to the cultures did not reverse the block on synergy by the inhibition. These data suggest that protein factors though they may be important in exerting qualitative control on the level of production of IFN‐γ have no role in the initial act

ISSN:0014-2980    

DOI:10.1002/eji.1830151103

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractA protein (eosinophil‐activating factor, EAF), which enhances the capacity of human peripheral blood eosinophils to kill antibody‐coated schistosomula ofSchistosoma mansoni, has been partially purified from supernatants of cultured peripheral blood mononuclear cells by sequential chromatography on Sephacryl S200 and DEAE‐cellulose. This protein is acidic with a molecular mass on gel filtration of 40 ± 7 kDa. It not only enhances the activity of eosinophils against schistosomula but also increases their ability to lyse antibody‐coated, herpes simplex virus‐infected Chang liver cells. It enhances the production of superoxide and hydrogen peroxide by eosinophils that occurs both spontaneously and in response to opsonized zymosan. However, increased respiratory burst activity does not appear to be responsible for the enhancement of eosinophil‐mediated killing of schistosomula, since a comparable or greater increase in hydrogen peroxide production is induced by column fractions that have little or no effect on schistosomulum killing. EAF enhances eosinophil degranulation, both spontaneously and after incubation with opsonized zymosan. Enhanced degranulation is associated with release of eosinophil peroxidase and eosinophil cationic protein. These findings suggest that EAF enhances the capacity of eosinophils to kill parasites by increasing the extent of eosinophil degranulation and the amount of toxic granule proteins that

ISSN:0014-2980    

DOI:10.1002/eji.1830151104

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractTo study early events during primary activation of human T cells, a simple method was developed which simultaneously allows positive selection of T cells from peripheral blood lymphocytes (PBL) and their polyclonal, antigen receptor‐mediated stimulation with anti‐T3 monoclonal antibodies. In the absence of accessory cells, T cells activated with matrix‐bound OKT3 express high levels of the Tac antigen within 15 h and produce interleukin 2 (IL 2). Tac expression was further enhanced by addition of exogenous IL 2. However, under these conditions purified T cells were unable to mount a proliferative response, whereas unfractionated PBL proliferated already after 24 h of culture. This unresponsiveness of purified T cells could be overcome by either re‐addition of low numbers of autologous accessory cells or semipurified human IL 1. As IL 1 had no significant effect on Tac expression of T3‐stimulated T cells, we conclude from these data that IL 1 exerts in addition to its influence on IL 2 production an effect, which allows antigen receptor‐triggered T cells to enter the

ISSN:0014-2980    

DOI:10.1002/eji.1830151105

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractTreatment of either rat peritoneal macrophages (RPM), cloned 3T3 fibroblasts (3T3FR) orTrypanosoma cruzitrypomastigote culture forms with human plasma fibronectin (huFN) enhanced their association with the untreated counterpart and this related to the concentration of huFN used. When treatment was performed at 4°C, the enhancing effect of huFN on parasite‐cell interaction was greater than that observed at 37 °C. This observation could be related to the indirect immunofluorescence antibody assay showing that a significant increase of fibronectin staining was observed on the cell and parasite surfaces upon incubation with huFN and that the extent of fibronectin staining was greater at 4°C. Incubation of huFN‐treated or nontreated parasites or cells with anti‐huFN antibodies exerted an inhibitory effect on the parasite‐cell association. The region of fibronectin that interacts with the trypomastigote surface is unknown. Inhibition experiments suggested that the domain of fibronectin which interacts with parasite surface receptors would probably be localized close to the NH2‐terminal region of the molecule. Taken together, these results suggest that fibronectin may play a role in the binding of parasites to the vertebrate host

ISSN:0014-2980    

DOI:10.1002/eji.1830151106

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractNude mice bearing allotype Ighbon a BALB/c genetic background (= CB nu/nu) are nonresponders to α(1 → 3)dextran (Dex), in contrast to BALB/c or BALB/c nu/nu. Although CB nu/nu mice accept transplants of congenic BALB/c, or BALB nu/nu lymphocytes, as shown by the expression of donor allotype Igha, they are not permissive for a primary anti‐Dex response by the grafted cells. BALB/c or BALB nu/nu cells, however, give a strong anti‐Dex response when grafted ontoirradiatedCB nu/nu or CB23 (Ighb) euthymic mice.A thymus‐independent, radiation‐sensitive suppressor cell population is postulated, which specifically hinders the anti‐Dex response, and which is exhibited by strains bearing that portion of chromosome 12 which codes for CHallotype Ighb, not containing the germ‐line anti‐Dex V/D genes. The suppressive action of Ighblymphocytes could be demonstrated directly in staggered co‐tr

ISSN:0014-2980    

DOI:10.1002/eji.1830151107

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractMouse monoclonal antibodies (mAb), of either IgG2aor IgG2b isotypes, specific for the retinal S‐autoantigen (S‐Ag) or a pool of rat anti‐S‐Ag sera prevented experimental autoimmune uveoretinitis in Lewis rats when injected i.p. at the time of immunization. Control mAb of the same isotypes, irrelevant to S‐Ag, had no inhibitory effect. The humoral response to S‐Ag, as studied by enzyme‐linked immunosorbent assay using a mouse mAb specific for rat kappa chain, was moderately but significantly reduced in suppressed animals. The rapid disappearance of the injected mAb from rat sera, as measured using a rat mAb specific for mouse kappa chain, could be explained by its complexing with either autologous antigen released from the retina at the site of inflammation, or anti‐idiot

ISSN:0014-2980    

DOI:10.1002/eji.1830151108

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractCloned genes for human major histocompatibility complex (MHC) class I antigens were introduced by DNA‐mediated gene transfer into a high‐efficiency transfection recipient (HTR) cell line previously derived from mouse mastocytoma P815. Cell surface expression of HLA‐A3, AW24 and CW3 gene products on P815 transfectants was demonstrated by radioimmune assay and by flow cytometry. The human MHC class I gene products were apparently expressed on P815 transfectants in a form recognized by human cytolytic T lymphocytes (CTL). Human CTL generated in unidirectional mixed lymphocyte culture against AW24+donor lymphocytes clearly lysed P815‐HLA‐AW24+transfectant target cells, but not untransfected P815(HTR) controls. Moreover, P815‐HLA transfectants could stimulate in vitro a significant alloreactive human CTL response. Lysis of P815‐HLA transfectant target cells by human CTL was inhibited by a monoclonal antibody directed against human MHC class I gene products. These mouse cell transfectants may be useful for the study of human T c

ISSN:0014-2980    

DOI:10.1002/eji.1830151109

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractThe rearranged μ and x genes from the 2,4,6‐trinitrophenyl (TNP)‐specific hybridoma Sp6 have been introduced into B cells from three different stages of differentiation as well as 5 non‐B cell lines to determine the levels and modes of immunoglobulin (Ig) gene expression. In pre‐B cells transformed with the μ and ϰ genes, low levels of Sp6‐ specific μ RNA were produced and approximately 210‐fold less μ and 800‐fold less ϰ proteins were produced than in the hybridoma Sp6. The Ig proteins were present intracellularly, but were not detected on the cell membrane. In mature surface sIg+B cell transformants, higher levels of μSp6and ϰSp6proteins and RNA were produced than in the pre‐B cell transformants (12 × μ, 70 × ϰ). These transformants displayed the μSp6and ϰSp6proteins on the cell membrane and also secreted the transfected Ig product. Plasma cell transformants produced the highest amounts of μSp6and ϰSp6proteins. These transformants secreted pentameric IgM but did not display detectable amounts of these proteins on the cell membrane.T cell and one fibroblast transformant produced Ig as normal sized μSp6and ϰSp6proteins. All other μSp6and ϰSp6non‐B cell transformants (melanoma, teratoma and macrophage) failed to produce enough Ig to determine whether the Ig proteins were of the correct molecular weights. The T cell and fibroblast transformants that produced Ig proteins did not secrete or display detectable Ig on the cell membrane. The expression of Ig did not inhibit the expression of the T cell anti

ISSN:0014-2980    

DOI:10.1002/eji.1830151110

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY

摘要:

AbstractA possible requirement for class II major histocompatibility complex (Ia) molecules in the initial activation of cytotoxic T lymphocyte precursors (CTLp) for allocytotoxic responses was investigated. To avoid possible interaction with other alloreactive cell types, a highly purified population of Lyt‐2+splenocytes was used as a source of CTLp. In the light of preliminary results indicating that Lyt‐2+CTLp, even in the presence of interleukin 2 (IL2), could best be triggered into mature CTLin vitroby cells known to be Ia+, we examined whether an interaction of CTLp with Ia antigens (either on syngeneic accessory cells or on allogeneic stimulators) played a role in the development of allocytotoxicity. Results from experiments done with C57BL/6 Lyt‐2+splenocytes co‐cultured with P815 stimulator cells and IL2 showed that the early activation of CTLp was independent of Ia+syngeneic accessory cells: (a) flow microfluorometry analysis of the responder population at the beginning or after 1 or 3 days of co‐culture did not reveal the presence of Ia+cells; (b) procedures for removal of residual Ia+cells or of dendritic cells from the responder population before co‐culture did not affect the development of cytotoxicity; (c) co‐culture with monoclonal antibodies against syngeneic Iabantigens did not inhibit the CTLp activation. By comparing an Ia+P815 tumor line with its Ia−clone as allogeneic stimulator cells, it was found that the CTLp activation was also independent of Ia alloantigen on the stimulator cells. The response against both the Ia+and the Ia−stimulator cell types was not inhibited by monoclonal anti‐L3T4 present in the co‐culture, indicating that these responses were not affected by resid

ISSN:0014-2980    

DOI:10.1002/eji.1830151111

出版商:WILEY‐VCH Verlag GmbH    

年代:1985

数据来源: WILEY