摘要:

AbstractThe present study was undertaken to determine if germinal center (GC) B cells are sufficiently activated to stimulate mixed leukocyte reactions (MLR). Percoll density fractionation and a panning technique with peanut agglutinin (PNA) were used to isolate GC B cells from the lymph nodes of immune mice. The GC B cells were treated with mitomycin C or irradiation and used to stimulate allogeneic or syngeneic splenic T cells in the MLR. Controls included high‐density (HD) B cells prepared from spleens of the same mice and HD B cells activated with lipopolysaccharide (LPS) and dextran sulfate. GC B cells bound high amounts of PNA (i.e., PNAhi). Similarly, the LPS‐dextran sulfate‐activated B cells were PNAhl. Treatment with neuraminidase rendered the PNA HD B cells PNAhl. GC B cells and the LPS‐dextran sulfate‐activated HD B cells stimulated a potent MLR, while the untreated HD B cells did not. However, following neuraminidase treatment, the resulting PNAhlHD B cell population was able to induce an MLR. The PNA marker appeared to be an indicator of stimulatory activity, but incubating the cells with PNA to bind the cell surface ligand did not interfere with the MLR. GC B cells were also capable of stimulating a syngeneic MLR in most experiments although this was not consistently obtained. It appears that germinal centers represent a unique in vivo microenvironment that provides the necessary signals for B cells to become highly effective antigen‐presenting cells.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.181

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractNet interleukin‐1 (IL‐1) inhibitor activity is induced by exposure of purified human monocytes‐macrophages to respiratory syncytial virus (RSV). Furthermore, IL‐1 inhibitor activity was produced by monocytes‐macrophages exposed to RSV in the presence of lymphocytes, that is, by unseparated mononuclear leukocytes (MNL). Purified RSV‐exposed lymphocytes, as well as the lymphocytes exposed within MNL preparations, produced net IL‐1 inhibitor activity. In contrast, net IL‐1 activity was produced when purified monocytes‐macrophages or unseparated MNL were exposed to influenza virus. The RSV‐induced IL‐1 inhibitors demonstrated antiproliferative effects on mitogen‐stimulated human lymphocytes as well as on the mouse thymocytes used in standard assays. The results raise the possibility that such antiproliferative activity is mediated, at least in part, by monocytes‐macrophages. The data also suggest that IL‐1 inhibitors produced by MNL after exposure to RSV may contribute along with other factors to the recurrence of RSV infection in immune individuals.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.189

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractMonoclonal antibodies were made by standard procedures using mononuclear cells isolated from hamster lung tissue to immunize the mice. The Moabs (G1.4, D7.5), secreted by the selected hybridomas, were isotyped as IgG2aKappa and were lytic in the presence of complement for 20% lymphocytes from lymph nodes or lung tissue; 40‐50% of lymphocytes from spleen or bone marrow; and 70‐80% of thymocytes or nylon wool nonadherent lung or lymph node lymphocytes. Functional studies showed that prior incubation of either Moab with enriched natural killer (NK) and T lymphocyte subpopulations did not interfere with effector: target conjugate formation but did block the ability of the effector cells to lyse NK‐sensitive targets. We conclude that the Moabs bind to a molecule(s) on NK and T lymphocytes. Further, the preincubation medium acquired the capacity to lyse preferentially NK‐sensitive targets but not NK‐lnsensitive targets. Interestingly, the Moabs were able to induce secretion of lytic factors from thymocytes and to induce resting peripheral T lymphocytes to acquire NK activity and release lytic factors. The ability of the Moab to signal release of lytic factors was retained even when monovalent Fab fragments were used; therefore, the Moabs initiate secretion by mechanisms that do not apparently involve crosslinking or Fc receptor interaction. G1.4 and D7.5 Moabs were functionally and antigenically crossreactive with human, rat, and hamster lymphocytes but not with mouse lymphocytes. Biochemical and immunochemical analysis showed that the G1.4 and D7.5 antigen on thymus cells and lung mononuclear cells has an apparent molecular weight of 27 kD. Although it is unlikely that there is an universal mechanism for secretion used by cells in general, it is interesting that Moab treatment of three different subpopulation of lymphocytes induced secretion of lytic factors and suggests that under physiologic conditions a common molecule might participate in induction of the secretion pathway. These studies lead to the hypotheses that 1) NK and T lymphocytes share a cell surface molecule that participates in signals that initiate secretion and that 2) the expression of the G1.4, D7.5 antigens precedes thymic differentiation.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.199

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractThe proliferation of human T lymphocytes induced by anti‐CD3 monoclonal antibodies (mAb) is used as a model for antigen‐induced activation via the T cell receptor‐CD3 complex. Since both systems are accessory cell (AC)‐dependent, an understanding of the role of AC in anti‐CD3‐induced proliferation may provide an understanding of physiological activation via the T cell receptor. Previous work has implicated receptor crosslinking as an important AC function. To determine its necessity in anti‐CD3‐induced lymphocyte proliferation, we prepared highly purified T lymphocytes and found that these cells did not respond to the anti‐CD3 mAb UCHT1, either alone or with interleukin 1 (IL1), interleukin 2 (IL2), or tetradecanoyl phorbol acetate (TPA). However, the response, as measured by appearance of IL2 receptors and proliferation, was restored by crosslinking with immobilized goat anti‐mouse antibodies (GAM) and did not require the addition of IL1, IL2, or TPA. Thus, crosslinking of CD3 receptors was a sufficient signal for proliferation of these cells. Cyclosporine A (CsA) inhibited the activation induced by immobilized UCHT1. Since macrophages are the principal targets of CsA‐mediated suppression of mitogen‐induced proliferation, but macrophages do not participate in the response to immobilized anti‐CD3, this may indicate that CsA was inhibiting crosslinking or a signal generated by it.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.214

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractTo study expression of a retroviral vector in human hematopoietic lineages, two established human hematopoietic cell lines (HL60 and K562) and a human adherent stromal cell line (KM101) were infected with the vector pZIP‐SV(X). Expression of the transferred neomycin resistance gene (neo) of pZlP‐SV(X) was evaluated as the ability of the cells to form colonies (>50 cells) in an agar assay in the presence of the neomycin analogue, G418. After infection, all three cell lines produced colonies resistant to G418. The level of neo mRNA in separate colonies was analyzed by Northern blot analysis. The neo gene transferred by the vector pZIP‐SV(X) was expressed in both human hematopoietic and stromal cell lines. In addition, primary adherent human stromal cells infected with pZIP‐SV(X) grew in the presence of G418. To determine if differentiation of hematopoietic cells affects expression of the retroviral vector, HL60 cells infected with pZIP‐SV(X) were induced to differentiate, and the level of neo mRNA measured. The amount of neo mRNA increased when HL60 cells were induced to differentiate along the granulocytic pathway. Conversely, when HL60 cells were induced toward monocytoid differentiation (TPA), the level of neo mRNA did not significantly increase. We conclude that the neo gene transferred by a retroviral vector, pZIP‐SV(X), is functionally expressed. In addition, expression of the transferred neo gene is regulated during myeloid differentiation of HL80 cells.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.221

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractIn this study we examine some of the phenotypic and functional characteristics that accompany the differentiation of monocyte‐macrophages from nonadherent precursors present in cord blood. Class II major histocompatibility complex (MHC) molecules identified by monoclonal antibody (mAb) L243 were the earliest monocyte‐macrophage‐associated antigens to be expressed. CD14 molecules, identified by mAb MO.2, and the transferrin receptor, identified by mAb OKT9, increased linearly over the 21‐day culture period. In contrast, FcγR were not expressed on these cells until 14 days of culture. FcγRI was present on approximately 80% of the cells, whereas FcγRII and FcγRIII were present on 30% and 20% of the cells, respectively.Functional activity of the nonadherent cell‐derived monocyte‐macrophages paralleled the phenotypic maturation of these cells. The capacity to stimulate a mixed leukocyte reaction paralleled the expression of class II MHC molecules. Similarly, the capacity to phagocytoseEscherichia coliandStaphylococcus aureusparalleled the appearance of CR3. Indeed, phagocytosis of these organisms was partially blocked by mAb OKM‐1. These studies demonstrate that monocyte‐macrophages derived from cord blood nonadherent mononuclear cells are a useful population with which to characterize human macrophage differentiation and functional and phenotypic heterogeneity.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.230

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractHuman peritoneal macrophages isolated from uremic patients undergoing peritoneal dialysis bind type 1 fimbriatedEscherichia coliin the absence of opsonins. The number of bacteria bound per macrophage was 6.9, as determined by microscopic examination. Methyl α‐mannoside (0.1 mM) andp‐nitrophenyl α‐mannoside (0.01 mM) inhibited this binding by about 66%. The ability of peritoneal macrophages to bindE.coliin a mannose‐specific manner was confirmed in further experiments using an enzyme‐linked immunosorbent assay (ELISA) with an antibacterial antibody, radiolabelledE.coli, and counts of colony‐forming units (CFU). The number of bacteria bound per macrophage was 7 to 12 in the ELISA and 5.5‐8.5 in the CFU assay. Methyl α‐mannoside caused 70% inhibition of binding In the ELISA and 84% in the CFU assay, whereasp‐nitrophenyl α‐mannoside showed inhibition of 79% and 90%, respectively. Most bound bacteria (76‐80%) were subsequently killed. NonfimbriatedE.coli827 bound poorly to the macrophages (~22%) as compared to that of the fimbriated bacteria. Although this binding was not inhibited by methyl α‐D‐mannoside orp‐nitrophenyl α‐mannoside, the percentage of bacteria killed was similar to that of the fimbriated phenotype. The peritoneal macrophage is thus able to phagocytoseE.coliin the absence of opsonins. This may explain the relative rarity ofE.colias an etiologic agent of peritoneal infections in the dialysed patient.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.239

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractA set of seven monoclonal antibodies (moabs) has been shown to discriminate in situ between distinct subpopulations of macrophages in the rat. It is still controversial if this heterogeneity is caused by the existence of different lineages or by differentiation of a common precursor. In both cases, the differentiation process might be regulated by microenvironmental factors. The present study examines the expression of the macrophage markers recognized by the seven ED‐moabs in bone marrow and monocyte cultures. Furthermore, the impact of culture time and stimulating factors on the antigen expression in these cultures was tested. The expression of the ED3 antigen is highly inducible in bone marrow cultures. Factors that might be responsible for the increased ED3 expression are investigated. This strong ED3 expression by bone marrow‐derived macrophages is nearly absent by monocyte‐derived macrophages. This implies that the ability to express ED3 is blocked before the macrophage precursor cells enter the circulation to become monocytes. The ED2 expression cannot be induced under the tested circumstances during culture. The expression of ED7 and ED8 is also highly inducible because bone marrow macrophages in vivo do not express these antigens. In culture, these macrophages stain positive for these markers already after the first day of culturing. The other three antigens are expressed on all macrophages under all tested circumstances.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.246

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractTreatment of mice with endotoxin (lipopolysaccharide, LPS) and the two LPS‐induced monokines, tumor necrosis factor (TNF) and interleukin‐1 (IL‐1), caused a depression of liver cytochrome P‐450 and related drug‐metabolizing enzymes, as well as other acute‐phase changes including increase in plasma fibrinogen levels and hypoferremia. However, only IL‐1, not TNF or LPS, depressed cytochrome P‐450 in cultured hepatocytes, suggesting that the effect of TNF in vivo might be mediated by a second mediator. TNF‐or LPS‐stimulated monocytes released a factor capable of depressing cytochrome P‐450 in cultured hepatocytes. This factor was inhibited by anti‐IL‐1 antiserum, and its synthesis, like that of IL‐1, was inhibited by dexamethasone (DEX). Pretreatment of mice with DEX protected against the depression of liver cytochrome P‐450 by LPS or TNF but not by IL‐1, suggesting that IL‐1 directly depresses cytochrome P‐450 and that DEX acts by inhibiting IL‐1 synthesis in vivo induced by LPS or TNF. However, DEX did not inhibit two other effects of LPS and TNF in vivo: increase of plasma fibrinogen levels and decrease of plasma iron, suggesting that these might not be mediated by IL‐1. Therefore, the effect of DEX in vivo, although supporting the hypothesis that depression of liver cytochrome P‐450 by LPS and TNF is mediated by IL‐1, indicates the existence of IL‐1‐independent pathways in the acute‐phase response.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.254

出版商:Wiley    

年代:1989

数据来源: WILEY

摘要:

AbstractAdult male Lewis rats received a single intravenous injection of 5‐bromo‐2′‐deoxyuridine (BRDU) to label all proliferating cells in the S‐phase of the cell cycle. Various lymphoid organs were removed 1 and 24 hr after injection to assess local proliferation and migration of newly formed cells, respectively. In ceil suspensions, surface staining was performed for macrophage subsets (ED1, ED2, ED3), and the DNA label BRDU was detected by a monoclonal antibody. Local proliferation of ED1+macrophages occurred in all organs investigated with the exception of the blood. Bone marrow outweighed the other organs by far; in addition to the proliferating ED1+promonocytes, the bone marrow also contained BRDU‐labeled ED2+macrophages. Newly formed ED1+monocytes migrated into lymphoid organs such as the mesenteric lymph nodes and spleen where they comprised about 90% of newly formed macrophages. In the spleen, ED3+macrophages seemed to be renewed by local proliferation, whereas in the mesenteric lymph nodes these cells were replaced by immigration. The heterogeneity of macrophages was further demonstrated by the different renewal of splenic macrophages. ED1+and ED3+cells were replaced in a matter of days, whereas it would probably take several months to renew ED2+cells.

ISSN:0741-5400    

DOI:10.1002/jlb.46.3.263

出版商:Wiley    

年代:1989

数据来源: WILEY