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F Kierszenbaum

Publications and source records attributed to F Kierszenbaum.

At least 91 records · Page 5Linked to original sources
PubMed1985

Role of surface N-acetylglucosamine residues on host cell infection by Trypanosoma cruzi.

We studied the role of surface GlcNAc residues on the surface of invasive (mouse-blood and insect-derived trypomastigotes) and non-invasive amastigote forms of Trypanosoma cruzi on parasite association with (i.e., surface binding plus internalization) macrophages and heart myoblasts. Removal of GlcNAc from the three forms of the parasite with beta-N-acetylglucosaminidase markedly increased the number of organisms per 100 cells and caused the organisms to associate with a greater percentage of host cells. N-Acetylglucosaminidase did not produce this effect after heat-inactivation and a substrate of the enzyme, N,N'-diacetylchitobiose, reduced it when it was present during the enzymatic treatment. The N-acetylglucosaminidase effect on T. cruzi was reversible after 2.5 h. When macrophages or myoblasts were treated with N-acetylglucosaminidase, their capacities to associate with blood or insect-derived trypomastigotes was reduced. Since removal of GlcNAc residues from the parasite surface increased their association with the host cells, GlcNAc would appear to interfere with the association process. On the other hand, GlcNAc residues on the host cell appear to favor the association.

Acetylglucosamine↗
PubMed1985

Increased host cell-Trypanosoma cruzi interaction following phospholipase D treatment of the parasite surface.

We examined the effect of phospholipase D (PLD) treatment on the ability of Trypanosoma cruzi to interact with phagocytic and nonphagocytic host cells. The presence of PLD during the incubation of parasites with mouse peritoneal macrophages caused significant increases in both the number of parasites per 100 macrophages and the percentage of macrophages associated with parasites. Parasites pretreated with PLD, washed, and then incubated with untreated macrophages showed a marked increase in parasite-host cell association. In contrast, when only the macrophages were pretreated with PLD, there was no significant change in the association. Parasites required 45 min of PLD treatment before a significant enhancement in parasite-host cell association was observed. The action of PLD could be blocked by the presence of a competitive substrate, phosphatidylethanolamine, during enzyme treatment. The enhancing effect of PLD treatment of the parasites was relatively long lasting since it was still seen 3 h after the enzyme had been removed. The enhancing effect of PLD probably reflected an increased capacity of T. cruzi to associate with host cells rather than increased phagocytosis of PLD-altered parasites by macrophages since similar results were obtained when rat heart myoblasts, which are not phagocytic, were used as host cells. Neither the presence of phospholipids or PLD phospholipid cleavage products during the incubation of T. cruzi with macrophages had any effect on parasite-host cell association. These results show that PLD-mediated alterations to parasite phospholipids increase parasite-host cell association, and suggest that these phospholipids play a role in the initial stages of host cell infection by T. cruzi.

Animals↗
PubMed1985

Effects of leukotriene C4 on macrophage association with and intracellular fate of Trypanosoma cruzi.

Leukotriene C4 (LTC4) enhanced the association of mouse peritoneal macrophages (MPM) with Trypanosoma cruzi, increasing the proportion of MPM associating with parasites and the number of trypanosomes per MPM. LTC4 affected both cells since pretreatment of either one increased the association. LTC4 also enhanced MPM uptake of killed T. cruzi or latex beads, denoting stimulation of phagocytosis. However, since LTC4 pretreatment of rat heart myoblasts--nonphagocytic cells--also increased the association, host cell membrane alterations induced by LTC4 may also facilitate parasite invasion. Inhibition of MPM guanylate cyclase abrogated the LTC4 effect, suggesting a role for elevated levels of cyclic GMP. LTC4 also increased the rate of intracellular parasite killing by MPM. These results suggest that LTC4, occurring in inflammation such as develops in T. cruzi infection, regulates parasite clearance by MPM by increasing uptake and intracellular destruction.

Animals↗
PubMed1985

The effect of swainsonine on the association of Trypanosoma cruzi with host cells.

The role of glycoprotein processing in Trypanosoma cruzi association with mammalian host cells (i.e., surface binding and internalization) was studied by using swainsonine - an inhibitor of glycoprotein processing. The presence of swainsonine in co-cultures of blood forms of T. cruzi with either mouse peritoneal macrophages or rat heart myoblasts markedly reduced parasite-host cell association as evidenced by significant decreases in both the percentage of cells associating with the organisms and the number of parasites per cell. This inhibition appeared to result from effects on both the parasite and the host cells since pretreatment of either one reduced its association with the untreated counterpart. The inhibitory effect of swainsonine on the host cells was demonstrable with trypomastigote forms derived from either infected mouse blood or the feces of infected insect vectors, and also with amastigotes. Conversely, treatment of the parasites with swainsonine inhibited their association with the host cells. Studies with blood trypomastigotes revealed that the swainsonine effect was reversible within 3 h. Two observations suggested that swainsonine had induced the parasite to produce defective oligosaccharides rich in mannose. First, swainsonine-treated organisms displayed a greater capacity to bind concanavalin than medium-treated organisms. Second, presence of alpha-methyl mannoside reduced such increased concanavalin A binding. Taken together, the present results suggest important roles for glycoprotein processing and oligosaccharide structures on the surface of both T. cruzi and its host cells in the initial stages of host cell infection.

Alkaloids↗
PubMed1985

Enhancing effects of gamma interferon on phagocytic cell association with and killing of Trypanosoma cruzi.

The effects of gamma interferon (IFN-gamma) on P388D1 cell or mouse resident peritoneal macrophage association (i.e., binding and internalization) with the protozoan Trypanosoma cruzi were studied, as well as the effects of this lymphokine on intracellular parasite killing. Incubation of either type of cell with a conditioned medium containing IFN-gamma and traces of interleukin 2 markedly increased the capacities of the cells to associate with virulent blood forms of T. cruzi, as evidenced by significant increases in both the proportion of parasite-associated cells and the number of parasites associated with the cells. Three lines of evidence pointed to IFN-gamma, and not interleukin 2, as the lymphokine responsible for the noted effect. First, a conditioned medium containing interleukin 2 but not IFN-gamma failed to enhance P338D1 cell-parasite association. Second, treatment of the IFN-gamma preparation at pH 2 to selectively inactivate IFN-gamma reduced its enhancing effect. Third, recombinant IFN-gamma, devoid of other lymphokines, also enhanced parasite association with P388D1 cells. Incubation of P388D1 cells with IFN-gamma for 24, 48, or 72 h increased cell association with T. cruzi, whereas a 12-h incubation period was insufficient, suggesting that IFN-gamma triggered time-dependent cellular events leading to the enhancement. Treatment of mouse resident peritoneal macrophages with the IFN-gamma-containing conditioned medium also increased the capacity of these cells to kill internalized trypanosomes. P388D1 cells, which showed minimal or no cytotoxicity after mock treatment with medium, displayed cytotoxicity after incubation with the IFN-gamma-containing conditioned medium; similar results were obtained with recombinant IFN-gamma. Catalase prevented parasite killing by P388D1 cells, indicating that H2O2 mediated the cytotoxicity. These results, underscoring the regulatory effects of IFN-gamma on macrophage-parasite interactions, suggest a possible role for this lymphokine in the mechanisms of host defense active against T. cruzi infection.

Animals↗
PubMed1985

Stimulatory effects of leukotriene B4 on macrophage association with and intracellular destruction of Trypanosoma cruzi.

The effects of leukotriene B4 (LTB4) on mouse peritoneal macrophage (MPH) association with and destruction of Trypanosoma cruzi were studied. The presence of 10(-8) to 10(-6) M LTB4 in co-cultures of MPH and T. cruzi enhanced their association (a term meaning surface binding and internalization), as evidenced by increases in the percentage of MPH associating with trypanosomes and the number of parasites per 100 MPH. Pretreatment of either parasites or MPH with LTB4 increased their association with the untreated counterpart, suggesting that the enhancement was a composite of effects on both cells. The effect of LTB4 on MPH was reversible, because normal levels of MPH-parasite association were recorded 60 min after the LTB4 pretreatment. However, the enhancement was demonstrable after the MPH were incubated with LTB4 for up to 24 hr, indicating that the effect lasted if LTB4 was present. Pretreatment with LTB4 also increased the capacity of MPH to take up glutaraldehyde-killed T. cruzi or latex beads, suggesting that LTB4 stimulated phagocytosis. Pretreatment of rat heart myoblasts--which are not phagocytic--with LTB4 also increased parasite association, suggesting that phagocytic ability was not an absolute requirement for production of the enhancement and that LTB4-induced alterations of the cell membrane facilitating parasite invasion may also be involved. An effect of LTB4 on MPH cytotoxicity was denoted by an increased rate of intracellular parasite killing. Two inhibitors of guanylate cyclase abrogated the enhancing effect of LTB4, suggesting that increased MPH levels of cyclic GMP--known to be increased by LTB4--mediated the effect. Because inflammatory cells, such as are found in acute chagasic lesions, are known to produce increased amounts of leukotrienes, the stimulatory effects of LTB4 could contribute to host defense against T. cruzi infection.

Adjuvants, Immunologic↗
PubMed1985

Lactoferrin effects on phagocytic cell function. I. Increased uptake and killing of an intracellular parasite by murine macrophages and human monocytes.

Mouse peritoneal macrophages (MPM) or human blood monocytes (HBM) co-cultured with intracellular (amastigote; AMA) forms of Trypanosoma cruzi in the presence of human lactoferrin (LF) took up greater numbers of organisms than in the absence of LF; the proportion of phagocytes taking up AMA was also significantly increased. Pretreatment of either MPM or AMA with LF also enhanced cell-parasite association. By immunofluorescence, HBM, MPM, and AMA were found to bind LF. By using 125I-labeled LF, each AMA was determined to have an average 1.1 X 10(6) surface receptors for LF. The enhancing effect of LF on cell-parasite association was inhibited when either rabbit anti-LF IgG or alpha-methyl mannoside (alpha-MM) was present during the incubation of MPM or AMA with LF, or when AMA pretreated with LF were then incubated with either of the LF blocking agents. Although these findings seemed to suggest that LF increased MPM-AMA association by bridging these cells, the LF effect was not inhibited when MPM pretreated with LF were subsequently incubated with either alpha-MM or anti-LF. Furthermore, LF stimulated phagocytosis, as denoted by a significant increase in latex particle uptake after LF treatment of MPM. The intracellular killing capacity of HBM or MPM was also stimulated by LF and was denoted by increased AMA destruction after LF treatments. The possibility that LF only appeared to increase the rate of AMA killing by simply promoting the engulfment of greater numbers of AMA that would then be destroyed intracellularly seemed unlikely because untreated MPM that had already taken up untreated AMA killed greater numbers of AMA when they were subsequently incubated with LF. The results of experiments with scavengers of oxygen reduction intermediates and of nitroblue tetrazolium reduction tests indicated that H2O2, O2- and 1O2 were involved in the killing of AMA by LF-treated MPM. These results suggest that LF, a glycoprotein secreted by neutrophils in greater than normal amounts during inflammation, may contribute to macrophage clearance of AMA released from infected host cells.

Animals↗
PubMed1984

Modulation of macrophage interaction with Trypanosoma cruzi by phospholipase A2-sensitive components of the parasite membrane.

The presence of phospholipase A2 (PLA2) significantly increased the association between Trypanosoma cruzi and macrophages. This effect reflected alterations to the parasite membrane since it was reproduced only when the parasite but not the macrophage was pretreated with PLA2. That PLA2 activity was responsible for the noted enhancement was indicated by the ability of the specific substrate phosphatidylcholine to block it. The presence of the PLA2 inhibitors quinacrine, 4-bromophenacyl bromide or phentermine markedly inhibited parasite-macrophage association. Quinacrine also inhibited association of the parasite with a non-phagocytic host cell. These results suggested a role for endogenous PLA2 in the initial stages of cell infection by T. cruzi.

Animals↗
PubMed1984

Host cell invasion by Trypanosoma cruzi: role of cell surface galactose residues.

Alpha-galactosidase treatment of blood, insect and intracellular forms of T. cruzi enhanced their ability to associate with mouse peritoneal macrophages or rat heart myoblasts as evidenced by significant increases in both the percentage of infected cells and the number of parasites per cell. The magnitude of the enhancement was greater with invasive (blood and insect) than with noninvasive (intracellular) forms of the parasite. The enzyme effect was reversible, attaining total recovery in 2.5 hr. By contrast, when either host cell was pretreated with the enzyme, the extent of cell-parasite association was significantly reduced. These results indicate that galactose residues on T. cruzi and host cells modulate their association in opposite ways.

Animals↗
PubMed1984

Changes in the levels of marker expression by mononuclear phagocytes in zinc-deficient mice.

To define the effects of dietary zinc deficiency on mononuclear phagocytes young adult A/J mice were fed zinc-deficient, zinc-adequate, or restricted amounts of a zinc-adequate diet for 28 days. The deficiency did not affect the total number or the percentage of nonspecific esterase (NSE)-positive cell populations in the blood or peritoneal cavity of the mice; however, the total numbers of leukocytes and NSE-positive cells in the spleen were reduced in the deficient and restricted mice to about 50% of the zinc-adequate group. In the peripheral blood of deficient mice, the percentages of adherent cells expressing Fc (FcR) and complement (CR) receptors were five and two times greater, respectively, than zinc-adequate controls. The FcR-bearing cells of the spleens of zinc-deficient mice were also increased twofold over controls. Adherent cells from the peripheral blood and spleen of zinc-deficient mice were able to phagocytize a slightly greater number of latex particles than cells from the zinc-adequate or restricted mice. The presence of zinc in fetal bovine serum did not enhance the ability of mononuclear phagocytes from deficient mice to engulf latex in vitro.

Animals↗
PubMed1984

Enhanced multiplication of intracellular (amastigote) stages of Trypanosoma cruzi in vitro.

Amastigotes of different strains of Trypanosoma cruzi responded to stimulation with concanavalin A in an axenic medium by increased DNA synthesis and cell multiplication. These effects were inhibited by alpha-methyl mannoside. Other mitogens, i.e. phytohemagglutinin P, castor bean ricin Type II isolated from Ricinus communis, and a bacterial lipopolysaccharide, had no effect on amastigote growth. Amastigote stimulation by concanavalin A lends itself to studies on the biochemistry and cell cycle of this human pathogen.

Animals↗
PubMed1984

Variations in expression of markers by populations of adherent cells from Trypanosoma cruzi-infected mice.

The kinetics of differentiation and maturation of phagocytic cells during the acute and chronic stages of experimental Chagas' disease was examined by monitoring changes in expression of peroxidase (PO), nonspecific esterase (NSE), C3b receptors (CR), Fc receptors (FcR), and phagocytic ability of cells in the blood, spleen, and peritoneal cavity. The significant changes recorded in the blood were: marked increases in the percentages of CR- and FcR-positive adherent cells during both the acute and chronic phase; Ia-positive cells increased two-fold in the acute period and remained elevated in the chronic stage. In the spleen, the major alterations recorded during both the acute and chronic stages were: two- to three-fold increases in the percentages of NSE- and PO-positive adherent cells and three- to four-fold increases in the proportions of CR- and FcR-positive cells. In addition, Ia-positive cells increased from 70% to approximately 90% of the adherent cell population. In the peritoneal cavity, a two- to four-fold elevation in the percentages of both PO- and NSE-positive cells was observed. The number of Ia-positive cells increased from 10% before infection to 85-90% during the acute phase and to 96-98% during the chronic period. All of the changes described above occurred in the absence of noticeable increases in phagocytic ability except for an elevation in the percentage of circulating latex-ingesting cells seen during chronicity. These results indicate that infection with Trypanosoma cruzi alters the pathways of differentiation of cells of the mononuclear phagocyte lineage.

Animals↗
PubMed1984

Macrophage activation by cord factor (trehalose 6,6'-dimycolate): enhanced association with and intracellular killing of Trypanosoma cruzi.

Cord factor (trehalose 6,6'-dimycolate[TDM] ), a mixture of 6,6'-diesters of alpha, alpha-D-trehalose with natural mycolic acids, has been described as having immunoregulatory and antitumor activities in vivo, although the relevant mechanisms of action remain unelucidated. In this work, we measured the effects of TDM on both mouse macrophage association with (i.e., the combined result of surface binding and uptake) and subsequent intracellular killing of Trypanosoma cruzi, the causative agent of Chagas' disease. Pretreatment of macrophage cultures with TDM for 16 h markedly increased both the ability of these cells to associate with T. cruzi and the rate of killing of parasites. The results obtained with macrophages treated with TDM after exposure to the parasites did not differ from those obtained with untreated macrophages, indicating that macrophage activation did not occur immediately after TDM treatment and was time dependent. The TDM effect was reversible since the extents of macrophage-parasite association and intracellular killing returned to normal levels 4 h after TDM treatment. Neither catalase, which scavenges hydrogen peroxide, nor sodium azide or potassium cyanide, which are inhibitors of peroxidase activity, significantly reduced the level of trypanosome killing by TDM-treated macrophages. TDM also increased the uptake of glutaraldehyde-killed T. cruzi and latex particles, suggesting that TDM could act mostly by enhancing phagocytosis and that increased cell association with the living trypanosomes did not necessarily depend on the macrophages becoming more susceptible to parasite invasion. These results indicate that TDM modulates macrophage function by augmenting both internalization and intracellular destruction. Hydrogen peroxide and peroxidase activity, postulated to be involved in phagocytic killing of T. cruzi, did not appear to be an absolute requirement for the killing of T. cruzi in TDM-treated macrophages.

Animals↗
PubMed1984

Alterations in production of immunoglobulin classes and subclasses during experimental Trypanosoma cruzi infection.

The spleens of mice infected with Trypanosoma cruzi were tested for their contents of cells producing IgM, IgG1, IgG2a, IgG2b, and IgG3 specific for the trinitrophenyl hapten after immunization with trinitrophenyl-Ficoll and trinitrophenyl-bovine serum albumin at various times during the acute and chronic phases of the disease. Reduced splenic contents of all of these cells was the characteristic of the acute period, and a return to normal levels occurred during the chronic stage. However, the density of IgG2a- and IgG2b-producing plaque-forming cells in the spleen was not restored to normality until 130 days postinfection, i.e., long after the chronic phase had been attained, reflecting a diluting effect of splenomegaly on cells that produce immunoglobulin isotypes known to be cytotoxic for the blood form of the parasite.

Animals↗