scholarly journals Studies of the macrophage complement receptor. Alteration of receptor function upon macrophage activation.

1975 ◽  
Vol 141 (6) ◽  
pp. 1278-1290 ◽  
Author(s):  
C Bianco ◽  
F M Griffin ◽  
S C Silverstein

We have examined the roles of Fc receptors and complement receptors in mediating the interaction of sensitized sheep erythrocytes (E) with activated and with nonactivated mouse peritoneal macrophages. Both activated and nonactivated macrophages ingest IgG-coated erythrocytes [E(IgG)]; activated cells intest 1.5-2 times as man E(IgG) as do nonactivated macrophages. Thus, there is a quantitative difference in Fc receptor-mediated ingestion between activated and nonactivated macrophages. There is, however, a qualitative difference in function of complement receptors of activated and nonactivated macrophages. Nonactivated macrophages avidly bind complement-coated E [E(IgM)Ia1, but do not ingest them to a significant degree. Activated macrophages, on the other hand, bind and ingest E(IgM)C. The possibility of Fc receptor participation in mediating ingestion of E(IgM)C by activated macrophages was eliminated by blocking Fc receptors with an antimacrophage IgG fraction. Activated macrophages treated with antimacrophage IgG did not ingest E(igG) but did ingest both E(IgM)C AND E(IgM)C. Nonactivated macrophages treated with antimacrophage IgG did not interact at all with E(IgG). These cells bound, but did not ingest, E(IgM)C and E(IgM)C. Complement receptor-mediated ingestion is a marker for macrophage activation and may be physiologically important in the elimination of complement-coated particles.

1979 ◽  
Vol 150 (3) ◽  
pp. 653-675 ◽  
Author(s):  
J A Griffin ◽  
F M Griffin

The function of complement receptors of mouse peritoneal macrophages was converted in vitro from mediating only attachment of macrophage complement receptor function was achieved by treating freshly explanted macrophages with supernates from cultures containing T lymphocytes and appropriately triggered macrophages. Fc receptor-mediated phagocyctosis by macrophages was required for the production of active supernates, for neither ingestion via the cells' complement receptors nor ingestion via nonimmunologic means was a sufficient stimulus for the macrophages' participation in the generation of supernatant activity. Fc receptor-triggered macrophages interacted by a contact dependent, but histocompatibility independent, mechanism with T lymphocytes, thereby signalling the lymphocytes to elaborate the active product. The possible significance of enhanced macrophage complement receptor function in inflammation, host defense against microbial pathogens, immune complex disease, and neoplasia is discussed.


1980 ◽  
Vol 152 (4) ◽  
pp. 905-919 ◽  
Author(s):  
F M Griffin

The effects of ingestion of soluble immune complexes upon macrophage phagocytic function was studied. Ingestion of immune complexes severely impaired the macrophage's ability to ingest IgG-coated particles but did not alter its ability to interact with particles by means other than its Fc receptors. Treatment of macrophages that had ingested immune complexes with supernates containing the previously described lymphokine that augments macrophage complement receptor function failed to enhance the cells' interaction with either IgG-coated erythrocytes or zymosan particles but markedly enhanced their ability to phagocytize via their complement receptors. The possible significance of these findings in immunologically mediated inflammation is discussed.


1984 ◽  
Vol 159 (1) ◽  
pp. 152-166 ◽  
Author(s):  
R Takemura ◽  
Z Werb

We have determined that the interaction of IgG-coated erythrocytes (EIgG) and complement-coated erythrocytes (EIgMC) with macrophage Fc and complement receptors, respectively, modulates the secretion of the neutral proteinases, elastase, and plasminogen activator. EIgG binding and ingestion stimulated secretion of elastase and plasminogen activator less than or equal to 6-fold and 20-fold, respectively, over the 3 d following treatment. Stimulation was dependent on the IgG titer bound to each erythrocyte and was detectable at greater than 6.2 X 10(3) molecules IgG/ erythrocyte (total 0.99 nM IgG in the culture). Cytochalasin B did not inhibit stimulation, indicating that the ingestion of ligands was not necessary. Binding of EIgG to the three subclass-specific Fc receptors (IgG2a, IgG2b/IgG1, IgG3) was effective. Stimulation of elastase secretion required continued exposure of ligands to cells for up to 24 h, whereas production of plasminogen activator, which has plasma membrane-bound forms as well as secreted forms, was stimulated by exposure for 2 h. The stimulated production of elastase and plasminogen activator by triggering Fc receptors was seen only when the initial secretion rates were low. Periodate- or thioglycollate-elicited macrophages, which have high rates of proteinase secretion, were not stimulated further. EIgMC, which are bound but not ingested by resident macrophages, stimulated elastase secretion transiently, and the rate of secretion returned to the control level by 24 h. Therefore, the mode of stimulation of neutral proteinase secretion by complement receptor differed from that of Fc receptor; stimulation by complement receptor possibly involves a limited release of enzyme from intracellular stores, rather than stimulating accelerated synthesis of enzyme. Erythrocytes coated with both complement and IgG showed both the transient increase in elastase typical of complement-mediated secretion and the sustained increase typical of Fc receptor-mediated secretion. These results suggest that macrophage Fc and complement receptors regulate secretion of proteinases by receptor-specific mechanisms.


1979 ◽  
Vol 150 (3) ◽  
pp. 607-621 ◽  
Author(s):  
J Michl ◽  
M M Pieczonka ◽  
J C Unkeless ◽  
S C Silverstein

We have examined the Fc- and complement-receptor function of resident and thioglycollate-elicited mouse peritoneal macrophages plated on surfaces coated with rabbit antibody-antigen complexes and with complement. We derive four major conclusions from these studies. (a) The trypsin-resistant Fc receptors of resident and thioglycollate-elicited macrophages are completely modulated when these cells are plated on rabbit antibody-antigen complexes. Residual Fc receptor activity is a result of the incomplete modulation of trypsin-sensitive IgG2a receptors. (b) The complement receptors of thioglycollate-elicited macrophages, but not of resident macrophages, are modulated when these cells are plated on complement-coated surfaces. The capacity of the two cell types to modulate their complement receptors is correlated with their ability to ingest complement-coated erythrocytes. (c) The complement and Fc receptors of both types of macrophages move independently of one another. (d) Complement masks the Fc segments of IgG in immune complexes thereby rendering them ineffective as ligands for macrophage Fc receptors.


1981 ◽  
Vol 153 (3) ◽  
pp. 514-519 ◽  
Author(s):  
B Diamond ◽  
D E Yelton

Monoclonal antibodies to sheep erythrocytes (SRBC) have proved useful in identifying two Fc receptors on mouse macrophages, one for IgG2a, and one for IgG1 and IgG2b. We have used monoclonal IgG3 anti-SRBC to identify a third Fc receptor on mouse macrophages which binds IgG3 uniquely. This receptor is present on primary resident and thioglycolate-induced peritoneal macrophages and on some macrophage cell lines. The binding of IgG3-coated SRBC is inhibited by aggregated byt not monomeric IgG3, and not by IgG1, IgG2a, and IgG2b aggregates. It is unaffected by treating the macrophages with trypsin or cytochalasin B and occurs at both 4 degrees and 37 degrees C. IgG3, like all other IgG subclasses, mediates phagocytosis. We have also generated a variant macrophage line which bears the receptors for IgG1 and IgG2b and for IgG2a, but not for IgG3.


1987 ◽  
Vol 165 (3) ◽  
pp. 733-749 ◽  
Author(s):  
A Ding ◽  
S D Wright ◽  
C Nathan

Several features of activation of mouse peritoneal macrophages were elicited by 1-2-d exposure to submicrogram concentrations of anti-Mac-1 (M1/70), a rat monoclonal antibody that reacts with the alpha chain of complement receptor type 3 (Mac-1). The changes induced included enhanced capacity to secrete H2O2 when triggered with PMA, decreased secretion of proteins, increased expression of Ia antigen and decreased phagocytosis of particles. These changes closely resembled those induced by rIFN-gamma in type, extent, and time course. The concentration of M1/70 IgG resulting in 50% of the maximal activation of macrophage H2O2-releasing capacity averaged 0.18 +/- 0.03 micrograms/ml. This activation was not blocked by anti-FcR mAb, and could be reproduced with M18/2, a mAb against beta chain of Mac-1, suggesting that a direct ligation of Mac-1 with mAb was responsible for the activation. Neither depletion of T cells nor addition of neutralizing Abs to IFN-gamma or TNF-alpha prevented M1/70-mediated macrophage activation. Moreover, F(ab')2 of M1/70, or plating of macrophages on C3bi-coated surfaces, inhibited the activation of macrophages by rIFN-gamma. These findings suggest that Mac-1 (CR3) may play an important role in macrophage activation.


2021 ◽  
Vol 8 ◽  
Author(s):  
Jing Liu ◽  
Zhaoyun Zong ◽  
Wenhao Zhang ◽  
Yuling Chen ◽  
Xueying Wang ◽  
...  

Macrophage activation is an important process in controlling infection, but persistent macrophage activation leads to chronic inflammation and diseases, such as tumor progression, insulin resistance and atherosclerosis. Characterizing metabolic signatures of macrophage activation is important for developing new approaches for macrophage inactivation. Herein, we performed metabolomic analysis on lipopolysaccharide (LPS)-activated macrophages and identified the associated changes in metabolites. Notably, the cellular Nicotinamide adenine dinucleotide+ levels were decreased while NADPH was increased, proposing that NAD+ restoration can inhibit macrophage activation. Indeed, supplementation of nicotinamide mononucleotide (NMN) increased cellular NAD+ levels and decreased cytokine productions in LPS-activated cells. Quantitative proteomics identified that nicotinamide mononucleotide downregulated the expressions of LPS-responsive proteins, in which cyclooxygenase-2 (COX-2) expression was significantly decreased in NMN-treated cells. Consequently, the cellular levels of prostaglandin E2 (PGE2) was also decreased, indicating that NMN inactivated macrophages via COX-2-PGE2 pathway, which was validated in activated THP-1 cells and mouse peritoneal macrophages. In conclusion, the present study identified the metabolic characteristics of activated macrophages and revealed that NMN replenishment is an efficient approach for controlling macrophage activation.


1980 ◽  
Vol 152 (2) ◽  
pp. 447-451 ◽  
Author(s):  
N Nogueira ◽  
S Chaplan ◽  
Z Cohn

Blood form trypomastigotes of the Y and CL strains of Trypanosoma cruzi were tested for their ability to enter and infect mouse peritoneal macrophages. Both strains failed to enter macrophages in appreciable numbers, whereas metacyclic trypomastigotes purified from acellular cultures were ingested with ease. Macrophage parasitization was enhanced manyfold after the removal of an antiphagocytic substance by trypsinization. This occurred without modification of parasite viability. Opsonization with hyperimmune mouse serum also enhanced the uptake of blood form trypomastigotes by macrophages. This effect was mediated by the macrophage Fc receptor. The effects of serum and trypsinization were additive at high parasite:cell ratios. Neither trypsin-mediated nor antibody-dependent opsonization of the organisms modified the fate of either strain within resident macrophages. However, lymphokine-activated macrophages were capable of destroying both strains, and antibody opsonization further enhanced this process.


1980 ◽  
Vol 152 (5) ◽  
pp. 1147-1161 ◽  
Author(s):  
BC Lane ◽  
J Kan-Mitchell ◽  
MS Mitchell ◽  
SM Cooper

Membrane proteins which selectively bind to the Fc portion of IgG were identified in the Nonidet P-40 extracts of radiolabeled thioglycollate- elicited mouse peritoneal macrophages. Affinity columns of various IgG preparations coupled to Sepharose 4B were used to absorb the Fc-binding proteins. Analysis of the acetic acid or sodium dodecyl sulfate (SDS) eluates from aggregated human IgG or antigen-complexed rabbit IgG columns revealed two Fc(gamma)/-specific proteins with apparent 67,000 and 52,000 mol wt. These proteins were not detected in acid or SDS eluates from F(ab')(2) columns or in eluates from IgG column, over which were passed lysates of Fc receptor-negative cells. With the use of affinity columns that contained aggregated mouse myeloma proteins of different IgG subclasses, we found that the 67,000-dahon protein selectively binds to IgG2a, whereas the 52,000-dalton protein binds to IgG1 and IgG2b. Neither protein was found in SDS eluates from IgG3 columns. Trypsin treatment of the macrophages before detergent lysis removed the 67,000-dalton protein, although it leaves intact the 52,000-dalton protein. These results provide structural confirmation for the existence of separate Fc receptors on mouse macrophages and indicate that the two Fc-binding proteins identified in this study represent all or part of the trypsin- sensitive Fc receptor which binds IgG2a and the trypsin-resistant Fc receptor which binds IgG2b and IgG1.


1977 ◽  
Vol 146 (1) ◽  
pp. 157-171 ◽  
Author(s):  
N Nogueira ◽  
S Gordon ◽  
Z Cohn

Infection of mice with Trypanosoma cruzi and subsequent intraperitoneal challenge with heat-killed trypanosomes elicits peritoneal macrophages which display in vitro microbicidal activity against trypomastigotes of T. cruzi. These cells also display other activated properties including rapid spreading, intense membrane activity, secretion of high levels of plasminogen activator, and ingestion mediated by the C3 receptor. An intravenous infection with BCG, followed by an intraperitoneal challenge with mycobacterial antigens brings about macrophages with similar properties. These criteria of macrophage activation were compared in normal and BCG- or T. cruzi-immune mice, with or without an intraperitoneal challenge with specific or unrelated antigens. Trypanocidal activity is displayed by both BCG- and T. cruzi-immune macrophages after intraperitoneal challenge with either antigen. Resident-immune macrophages from both T. cruzi- and BCG-infected mice show a trypanostatic, rather than trypanocidal activity. Macrophages from noninfected mice, challenged with the same antigens, show neither trypanostatic nor trypanocidal activity. Increased secretion of plasminogen activator shows a definite immunological specificity. Challenge with the specific antigen induces the appearance of macrophages secreting high levels of plasminogen activator, while unrelated antigens induce much smaller levels. Noninfected mice challenged with the same antigens do not display any enchancement in secretion. In contrast, increased spreading and phagocytosis mediated by the complement receptor are also displayed by cells from noninfected mice challenged with any of the agents tested.


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