摘要:

AbstractHistopathology revealed that nu/nu mice developed both acute and chronic inflammatory responses following infection withCryptococcus neoformans.In comparison to inflammatory responses in nu/+ mice, the responses in nu/nu mice were delayed, less intense, contained predominantly morepolymorphonuclear leukocytes(PMNs) than macrophages (Mφs), and did not develop into granulomas. In addition, nu/nu mice developed cryptococcal skin lesions demonstrating that C.neoformansis dermatotropic in a T‐cell deficient host. Quantitative culturing of infected organs confirmed that delayed and incomplete inflammatory responses observed in nu/nu mice correlated with their enhanced susceptibility toC. neoformans.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.533

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractWe obtained peripheral blood mononuclear cells (PBMC) from four healthy, tuberculin purified protein derivative (PPD) reactive donors and cultured these cells in media containing PPD (low dose = 200 ng/ml or high dose = 1 fig/ml). Five days after the addition of PPD, T cells were isolated, washed, and added to autologous adherent cell cultures at a 1:1 ratio. Adherent cells were then cultured for 24 h in media only (baseline), media plus lipopolysaccharide (LPS, 2 μg/ml; positive control), or media containing the prestimulated T cells. After 24 h, supernatants were harvested and interleukin 1β (IL‐β) levels were assayed by radioimmunoassay (RIA) or enzyme‐linked immunosorbent assay (ELISA). The results show that T cells prestimulated with low dose PPD (200 μg/ml) did not induce IL‐1 production by adherent cells (mean increase over baseline 0.2 ± 1.3 standard deviation [SD] ng/ml,P= 0.61). However, T cells prestimulated with high dose PPD (1 tig/ml) did induce adherent cells to secrete IL‐1β (mean increase over baseline 1.7 ± 0.62 [SD] ng/ml,P= 0.01), but this induction was abolished when cell‐to‐cell contact was prevented by use of double well chambers (mean increase over baseline 0.1 ± 0.36 [SD] ng/ml,P =0.69). Prestimulated T helper (CD4+) cells were able to induce monocytes to secrete IL‐1β but prestimulated CD8+T cells were not. These data suggest that when T helper (CD4+) cells are sufficiently activated they acquire the ability to induce monocytes to secrete IL‐1β. Cell‐to‐cell contact between monocytes and T cells is required. This function of activated T cells may be important in the normal cellular immune response.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.542

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractIn this study we used palmitate‐derivatized antibodies (pal‐Ab) to examine the minimum contribution of Fc receptors (FcR) to macrophage (Mφ)‐mediated lysis and phagocytosis in antibody‐dependent cellular cytotoxicity (ADCC). Pal‐Ab specific for chicken erythrocytes (CE) were incorporated into the plasma membranes of Mφ by insertion of the palmitate hydrocarbon chains into the outer leaflet of the phospholipid bilayer. In this system, the palmitate anchor bypassed the requirement for FcR in antibody‐dependent effector‐target conjugation and provided a unique opportunity to uncouple antibody‐FcR interactions in ADCC. We show that binding of CE targets by P388D1 Mφ effector cells through anti‐CE pal‐F(ab')2can lead to efficient extracellular target cell lysis, but not phagocytosis. In contrast, pal‐F(ab')2‐mediated interactions between CE and peritoneal exudate Mφ (PEM) activated both ingestion and extracellular lysis of the targets. In normal ADCC, FcR‐dependent interactions between CE and either P388D1 cells or PEM triggered both extracellular lysis and phagocytosis. Our results demonstrate that lysis and phagocytosis in CE‐directed ADCC by Mφ have different minimum requirements for FcR functions. Moreover, our results suggest that FcR‐independent triggers on the PEM surface are capable of triggering target cell lysis and internalization following antibody‐mediated interactions.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.548

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractTHP‐1 cells are a monocyte‐like cell line derived from a patient with acute monocytic leukemia and unlike other leukemic cell lines has a normal diploid karyotype. We have characterized FcγR expression on this cell line by flow cytometry, radiolabeled lgG1 and monoclonal antibody (mAb) binding assays, and biochemical analysis. Flow cytometric analysis of THP‐1 cells with anti‐FcγRI, II, and III mAb, and a rabbit anti‐FcγRIII F(ab')2 demonstrated that only FcγRI and FCγRII are expressed by these cells. A panel of anti‐FcγRIII mAb (anti‐CD16) failed to bind to THP‐1 cells. Biochemical studies identified polypeptides of 64 to 78 kDa (FcγRI) and of 42 to 53 kDa (FcγRII). FcγR expression was determined by binding of radioiodinated human lgG1 (to detect FcγRI), mAb IV.3 (to detect FcγRII), or rabbit IgG immune complexes. Thirty‐five thousand high affinity binding sites (dissociation constant [KD] = 4.22 × 10‐9M) for lgG1 were found on THP‐1 cells. Interferon‐γ (IFNγ) upregulated FcγRI expression by THP‐1 cells 2.8‐fold, whereas FcγRI on U937 cells was increased six‐ to eight‐fold by this cytokine. Phorbol myristate acetate (PMA), tumor necrosis factor‐α (TNFα), and vitamin D3 had no effect on lgG1 binding by THP‐1 cells. Fifty thousand IgG molecules in immune complexes bound to THP‐1 cells. IFNγ treatment increased this binding by four‐fold, PMA treatment resulted in a 50% increase in the number of IgG immune complexes bound, whereas vitamin D3 treated THP‐1 cells bound half as many IgG immune complexes as control cells. Binding assays utilizing mAb IV.3 identified 50,000 sites per cell. Treatment of THP‐1 cells with IFNγ, TNFα, PMA, or vitamin D3 had no effect on FcγRII expression. That FcγRI plays a predominant role in immune complex binding was demonstrated by inhibition studies. Human lgG1 as well as mouse lgG2a mAb to FcγRII inhibited immune complex binding by 76 to 84%, whereas mouse lgG1 mAb to FcγRII had minimal effect on immune complex binding. FcγR expression may not be linked to differentiation of THP‐1 cells since only 1,25 vitamin D3 was able to induce the expression of CD14, a marker of mature monocytic phenotype.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.556

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractThe accumulation of mononuclear phagocytes at sites of chronic inflammation is dependent on an increase in the rate of extravasation of blood‐borne monocytes through the vascular endothelium into the connective tissue. Once the monocytes have emigrated into the connective tissue, they may differentiate into tissue macrophages, presumably following interactions with extracellular matrix proteins. To study these processes, we tested the effects of cytokines and phorbol esters on the adhesion of U937 cells, a human monocyte‐like cell line, to cultured endothelial cells (EC) and to matrix proteins. In the absence of cytokines, very few of the U937 cells adhered to EC (5% or less in most experiments). When EC were pretreated for optimal periods of time (4–8 hr) with recombinant interleukin‐1α (IL‐1α), IL‐1β, tumor necrosis factor‐α (TNFα), or lymphotoxin (LT; also known as TNF‐β), 35–85% of the U937 cells were able to bind. Interferon‐γ (IFN‐γ) and interleukin–2 (IL‐2) did not stimulate U937‐EC binding, even though IFN‐γ was shown to increase EC adhesiveness for T lymphocytes. Phorbol esters also greatly stimulated U937‐EC adhesion but, in this case, the increase was due to an action on the U937 cells. A monoclonal antibody (MAb), 60.3, against the CD11/CD18 family of leukocyte adhesion molecules partially inhibited the adhesion of untreated and phorbol ester‐treated U937 cells to noncytokine‐treated EC. However, that MAb had no effect on U937 cell binding to TNF‐α‐treated EC. Thus U937 cells use both CD11/CD18‐dependent and ‐independent mechanisms to adhere to EC. In the absence of stimulating agents, only a small proportion of the U937 cells (2–20%) adhered to fibronectin (FN), and almost none bound to either laminin (LN) or gelatin (denatured type I collagen). In the presence of phorbol esters, a much larger proportion of the U937 cells adhered to FN, with only slight increases in the proportion of cells which bound to LN or gelatin. Additional adhesion assays performed in the presence of a pentapeptide containing the amino acid sequence arg‐gly‐asp (RGD), which is part of one of the cell‐binding domains of FN, demonstrated that the RGD‐containing peptide almost totally blocked the phorbol ester‐induced adhesion of U937 cells to FN. In contrast, the peptide had no inhibitory effect on the phorbol ester‐induced binding of U937 cells to EC.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.566

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractThe current results provide direct evidence for a role of tissue macrophages (Mφ) in natural immunity and support the use of immunomodulators to enhance antiviral resistance in immunocompromised individuals. In this study, macrophages (Mφ) in the spleen and liver were eliminated by intravenous (i.v.) injection of the drug dichloromethylene diphosphonate (DMDP) encapsulated in liposomes. The effect of this depletion system on peritoneal Mφ, peripheral blood leukocytes, splenic natural killer (NK) activity, and natural and immunomodulator‐induced host resistance was then assessed. Barrier‐maintained CD‐1 female mice were inoculated i.v. either with DMDP liposomes, free liposomes (containing no DMDP), or saline on day ‐2 or on days ‐3 and ‐1 before cell population analysis or infection. Single or double treatment with DMDP liposomes had no effect on peritoneal Mφ as indicated by no changes in total number, differential counts, or ectoenzyme patterns. Double treatment with DMDP liposomes caused a marked leukocytosis in blood, primarily of lymphocytes and polymorphonuclear leukocytes (PMN), and a transient depression of spontaneous and interferon‐inducible splenic NK activity. The effects on host resistance to i.v. infection withListeria monocytogenesor herpes simplex virus type 2 (HSV‐2) indicated that i.v. treatment with DMDP liposomes significantly reduced natural resistance to these microorganisms as evidenced by increased mortality and decreased median survival time. When DMDP liposomes‐treated mice were given the immunomodulator maleic anhydride divinyl ether copolymer (MVE‐2) intraperitoneally the day before infection with HSV‐2, the immunosuppressive effect of DMDP liposome treatment was significantly reversed.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.579

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractWe evaluated the effects of murine recombinant interleukin‐4 (rIL‐4) on murine peritoneal macrophages. We showed a marked, dose‐dependent stimulation of respiratory oxidative burst by IL‐4 in peptone‐elicited murine peritoneal macrophages. This effect was abolished by a neutralizing monoclonal antibody (mAb) to rlL‐4 confirming that the enhanced chemiluminescence was due to IL‐4. In contrast, rlL‐4 depressed the respiratory oxidative burst of a transformed murine macrophage cell line, J774, in a dose‐dependent mAb‐reversible manner.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.587

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractInflammatory macrophages from mice fed diets containing menhaden fish oil (MFO) have a reduced capacity for cytotoxicity of mastocytoma cells upon activation with interferon‐γ (IFNγ) and lipopolysaccharide due to an altered responsiveness to IFNγ. In an effort to elucidate further how dietary MFO effects macrophage function, we have studied the maturation of inflammatory macrophages from mice fed MFO compared with mice fed safflower oil (SFO) using several processes that serve as markers of the activational state. No significant differences in the recruitment or percentage of peritoneal exudate cells as macrophages after thioglycollate injection and no differences in spreading, binding, or phagocytosis of sheep erythrocytes or phagocytosis of yeast by inflammatory macrophages were observed when the dietary groups were compared. However, MFO macrophages had an altered capacity for peroxide release when stimulated with unopsonized zymosan (10–200 μg/ml). Furthermore, to elucidate how MFO feeding could alter IFNγ‐induced responses of inflammatory macrophages, we assessed phorbol‐12‐myristate‐13‐acetate‐induced hydrogen peroxide production and expression of class II MHC determinants (la). There were no differences between macrophages from mice fed the two diets with respect to the production of peroxide when they were preincubated with 0.1–10 U/ml of IFNγ. However, MFO macrophages had greater peroxide production after enhancement with 100 U/ml of IFNγ. With respect to la induction, the percentage of macrophages responding to IFNγ was not altered by diet, and there were no differences in expression of la induced by 24 hr exposure to IFNγ. Thus the differential effect of MFO compared with SFO is probably mediated not by an alteration in the maturation of inflammatory macrophages but rather through the alteration of IFNγ‐induced functions such as peroxide production.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.592

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractHuman neutrophils are phagocytic cells that can be activated by a variety of agonists to undergo a group of physiologic responses. This “stimulus‐response” coupling is thought to be dependent on the phosphorylation of specific proteins. We have previously shown that, in addition to the widely distributed serine and threonine protein kinases, neutrophils contain tryosine protein kinase activity in the cell cytosol and particulate fractions. When neutrophils are treated with a variety of agents, phosphorylation of both cytosolic and particulate proteins on tyrosine residues occurs. Increases in tyrosine phosphorylation may be a result of increases in the activity of tyrosine kinases or a decrease in the activity of phosphotyrosine phosphatases. In this study, we have used a novel nondenaturing polyacrylamide gel electrophoretic method to demonstrate that treatment of human neutrophils with the chemotactic peptide FMLP or the phorbol ester phorbol myristate acetate induces a time‐ and concentration‐dependent increase in the tyrosine protein kinase activity found in the cell cytosol and cell particulate fraction. The time course and concentration range over which these changes occur are similar to those seen for activation of the neutrophil oxidative burst and phosphorylation of proteins on tyrosine residues, suggesting that these events may be related.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.599

出版商:Wiley    

年代:1991

数据来源: WILEY

摘要:

AbstractAlthough the CD4 molecule is the cellular receptor for human immunodeficiency virus‐1 (HIV‐1) in cells of the lymphocyte/monocyte lineage, a number of investigators have also been able to infect cells, including several of central nervous system (CNS) origin, that do not express CD4 protein or mRNA. These infections are generally nonpermissive. To ascertain whether the nonpermissive nature of infection in glial cells is due to an inefficient entry pathway, we prepared a permanently transfected U373‐MG cell line expressing the CD4 molecule and demonstrated that HIV‐1 still replicates at a low level. Furthermore, a virus uptake assay indicated that HIV‐1 enters glial cells effectively, even in the absence of CD4. These results demonstrate that HIV‐1 entry is efficient and that the restrictive nature of the infection in glial cells is due to postentry mechanisms. In addition, these findings support the existence of an alternate, efficient, entry pathway in some glial cells.

ISSN:0741-5400    

DOI:10.1002/jlb.49.6.605

出版商:Wiley    

年代:1991

数据来源: WILEY