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Cytoplasmic granule formation in myelocytes. An electron microscope radioautographic study on the mechanism of formation of cytoplasmic granules in rabbit heterophilic myelocytes.

The intracellular flow of tritiated lysine as revealed by electron microscope radioautography was studied in heterophilic myelocytes of rabbit marrow. Label over the Golgi complex rose to a maximum of 37% of total cytoplasmic grains 30 min after initial exposure to the tracer and fell to 11% after 3 to 4 hr of incubation. Coincident with decrease in label over the Golgi complex, grain counts over granules rose to 32% after 3 to 4 hr. The time sequence of incorporation and flow of tritiated lysine and the per cent distribution of label was similar in bone marrow myelocytes under in vivo and in vitro conditions. The results demonstrate a function of the Golgi complex in incorporating or packaging certain basic amino acids or proteins into cytoplasmic granules of heterophilic myelocytes.

Animals↗

[Two cases of acute lymphoblastic leukemia with cytoplasmic granules].

The presence of cytoplasmic granules in blastoid cells of patients with acute leukemia is generally accepted as a useful morphological marker for differentiation of myeloid leukemia from lymphoblastic leukemia. We diagnosed two cases of acute lymphoblastic leukemia(ALL) with cytoplasmic granulation. Surface marker analysis of leukemic cells revealed they were positive for CD10, 19, 20, 33, 34 and HLA-DR. Immunoglobulin gene rearrangement was detected by means of Southern hybridization with an Ig-JH probe for both patients. On the basis of these findings, the patients were diagnosed as having B-precursor ALL. Electron microscopic observation showed no myeloperoxidase activity, so that the granules were considered to be related to autophagolysosomes. This experience demonstrates that the recognition of the presence of granular ALL is necessary for making an accurate differential diagnosis of acute leukemias.

Child↗

Differences in the behavior of cytoplasmic granules and lipid bodies during human lung mast cell degranulation.

We used a morphometric and autoradiographic approach to analyze changes in specific cytoplasmic granules and cytoplasmic lipid bodies associated with human lung mast cell degranulation. Mast cells were dissociated from lung tissue by enzymatic digestion and were then enriched to purities of up to 99% by countercurrent centrifugation elutriation and recovery from columns containing specific antigen bound to Sepharose 6 MB. Degranulation was induced by goat anti-IgE. At various intervals after stimulation, parallel aliquots of cells were recovered for determination of histamine release or were fixed for transmission electron microscopy. We found that lipid bodies, electron-dense structures that lack unit membranes, were present in both control and stimulated mast cells. Autoradiographic analysis showed that lipid bodies represented the major repository of 3H-label derived from [3H]arachidonic acid taken up from the external milieu. By contrast, the specific cytoplasmic granules contained no detectable 3H-label. In addition, lipid bodies occurred in intimate association with degranulation channels during mast cell activation, but the total volume of lipid bodies did not change during the 20 min after stimulation with anti-IgE. This result stands in striking contrast to the behavior of specific cytoplasmic granules, the great majority of which (77% according to aggregate volume) exhibited ultrastructural alterations during the first 20 min of mast cell activation. These observations establish that mast cell cytoplasmic granules and cytoplasmic lipid bodies are distinct organelles that differ in ultrastructure, biochemistry, and behavior during mast cell activation.

Antibodies, Anti-Idiotypic↗

Cytoplasmic granules in exfoliated buccal epithelial cells.

The cytoplasmic granules in exfoliated epithelial cells of healthy cheek mucosae of seven subjects were studied by means of phase-contrast microscopy, electron microscopy and histochemistry. An electron microscopic technique was used to study specific granules which had been identified with the light microscope. Phase-contrast microscopy revealed that the cytoplasmic granules are present in unfixed material. Ultrastructurally they consist mostly of discrete, dense granular bodies. Also seen were collections of electron-dense masses, collections of organelles and organelles mixed with granular bodies and electron-dense masses. Histochemically they stain like keratohyalin. No lipids were detected. We propose that the discrete bodies are normal keratohyalin granules and the electron-dense masses are granules in stages of disintegration. When the granules break down they become mixed with organelles. The keratohyalin granules are the darkly-stained granules seen microscopically, and the disintegrating granules and collections of organelles the weakly-stained, indistinct cytoplasmic granules.

Adult↗

Cytolytic activity of purified cytoplasmic granules from cytotoxic rat large granular lymphocyte tumors.

Purified cytoplasmic granules from cytotoxic rat large granular lymphocytes (LGL) tumors were cytolytic to erythrocytes, splenocytes, and a number of different lymphoid tumor cells. Granule concentrations of approximately 1 microgram/ml granule protein were adequate to lyse 100% of the erythrocytes, while the nucleated cells required up to 100 micrograms/ml granule protein to achieve complete lysis. Cytoplasmic granules purified from noncytotoxic lymphoid cells did not contain detectable cytolytic activity; purified granules from rat mast cells and rat liver lysosomes likewise failed to display cytolytic activity. However, granules prepared from normal rat peripheral blood LGL were cytolytic. Granule-mediated lysis of erythrocytes and nucleated cells was complete within 3 min at room temperature. The lytic activity required calcium at concentrations of 10(-4)-10(-2) M; magnesium or barium failed to replace calcium, while strontium could replace calcium at 10(-3)-10(-2) M when nucleated cells were the target. Exposure of LGL tumor granules to calcium before the addition of target cells resulted in an inactivation of granule cytolytic activity over the course of 20 min at room temperature. Granule cytolytic activity was heat and Pronase sensitive, and could be solubilized by 2 M salt. Examination of granules exposed to calcium in the electron microscope using negative staining showed that calcium treatment of granules results in the formation of ring-shaped structures previously described to be associated with LGL-mediated cytotoxicity. These results provide support for the hypothesis that the cytotoxic processes mediated by LGL are a secretory event characterized by the release of cytolytic material from the cytoplasmic granules after triggering by a surface receptor. The results further suggest that the ring structures visible in the electron microscope are associated with the lytic event.

Animals↗

The kinetics of cytoplasmic granule secretion in natural killer cytotoxicity.

Antiserum against purified cytoplasmic granules from rat LGL tumor cells, and protein A-gold immunoelectron microscopy were used to study the secretory events in lysis of YAC-1 tumor cells by rat LGL tumor cells or by isolated LGL from normal rats. After 30 min incubation of effector and target cells together, gold-labeled cytoplasmic granules were often seen concentrated in the area of the LGL adjacent to the bound YAC-1 target. Within 60 min, the granules were observed to move to the cell border near the conjugated site. At this point, the granules were fused with the cell membrane, and subsequently released the gold-labeled contents into the junction between the LGL and the target cell. Gold particles could be seen at the E-T interface, on the LGL surface, or sometimes on the target cell surface. These data provide direct evidence for the hypothesis that under conditions of active cytotoxicity, natural killer cells secrete their cytoplasmic granule contents leading to the deposition of granule material on the target cell surface and the eventual lysis of the cell.

Animals↗

Purification and properties of cytoplasmic granules from cytotoxic rat LGL tumors.

To evaluate the role of NK cell granules in the lytic activity of NK cells, cytoplasmic granules of rat NK tumors were purified by centrifugation of the cell homogenates in a Percoll gradient. Analysis of such gradients showed a band of light-scattering material near the bottom of the tube; assay of gradient fractions for lytic activity against SRBC showed a potent lytic activity giving a sharp peak in this region. Complete lysis of SRBC was achieved with less than 1 microgram/ml protein of the most active fractions. Examination in the electron microscope showed that a pool of fractions containing lytic activity consisted of pure cytoplasmic granules showing similar morphology to those found in the LGL tumors. The lytic band was associated with a peak in the activity of four different lysosomal enzymes. Analysis of Percoll gradient fractions showed that marker enzymes for mitochondria, plasma membrane, and cytosol were well separated from this activity peak. Analysis of the Percoll gradient fractions by SDS gel electrophoresis showed that this granule fraction was free of contamination of proteins from other parts of the gradient. The granules contained major protein bands of 62, 58, 30, 29, and 28 kilodaltons. In addition to protein, the purified granule fractions contain hexose and uronic acid, but no nucleic acids or phospholipids were detected in chemical assays. Major amounts of chymotryptic, tryptic, and elastase activities were not present, nor were peroxidase or lysozyme activities detectable in substantial amounts. These data show that NK tumor cell cytoplasmic granules contain a potent lytic activity and have biochemical properties that distinguish them from granules present in granulocytes and mast cells.

Animals↗

Inhibition of NK and ADCC activity by antibodies against purified cytoplasmic granules from rat LGL tumors.

Highly purified preparations of cytoplasmic granules from transplantable rat large granular lymphocyte (LGL) tumor lines (rat natural killer (RNK) tumors) were used to immunize rabbits. Antibodies from these animals gave two precipitin lines with granule extracts in Ouchterlony experiments. They reacted with at least four different bands on nitrocellulose blots of SDS gels of LGL granule proteins. By immunofluorescence, specifically adsorbed antigranule antibodies did not recognize LGL or T cell surface antigens but reacted with the cytoplasmic granules in permeabilized RNK tumor cells as well as with normal rat LGL. These same antisera showed little or no reactivity with a panel of other cells, including peripheral blood T cells, thymocytes, macrophages, and EL-4 tumor cells. F(ab')2 preparations of these antigranule antibodies completely blocked granule-mediated lysis of both SRBC and nucleated targets, while control F(ab')2 preparations from rabbits immunized with EL-4 granules or TNP-KLH showed no significant inhibition of this cytolytic activity at the same antibody concentration. Anti-granule F(ab')2 preparations specifically inhibited (greater than 75%) rat natural killer (NK) and antibody-dependent cellular cytotoxicity (ADCC) activities in a dose-dependent manner but did not effect cytotoxic T cell activity. Pretreatment of either effectors or targets by these antibodies had no effect. Anti-granule F(ab')2 preparations, at concentrations showing strong inhibition of lysis, did not inhibit the binding of LGL to YAC-1 or Ab-coated P815 targets. These results demonstrate that a granule component(s) is necessary for the lytic activity of LGL in both NK and ADCC and provide the first direct evidence that a secretory event involving these granules is part of the lytic process.

Animals↗

Quantitative analysis of the movements of cytoplasmic granules in polarized fibroblasts.

Movements of cytoplasmic organelles were analyzed in Vero fibroblasts. In the cells polarized at the edge of an experimental wound, cytoplasmic granules moved randomly (Brownian motions) and by separate jumps (saltatory movements). The displacement of granules by the Brownian motions exceeded by more than an order of magnitude that of the mitochondria similar by weight. Lipid droplets moved predominantly by saltations, whereas mitochondria and lysosomes moved much less often. In a front part of the polarized cells, the main directions of saltatory movements were from the nucleus to the leading edge of a cell and back, whereas the tangential movements (across the long axis of a cell) were less than 1%. 90% of saltatory movements occurred in the area starting 10-12 microm from the nucleus and ending 10-12 microm from the leading edge of a cell. The average rate of saltatory movements of the granules (2.38 microm/s) was identical in both directions. The average length of the track was 7.49 microm; the maximum track length reached 30 microm. An increase in the granule diameter from 0.3 to 1.4 microm resulted in a minor (statistically insignificant) decrease in the average rate of the movements. The average rate of saltatory movements of mitochondria was 1.00 microm/s, and the average track length was 6.04 microm. Therefore, mitochondria, in contrast to lipid droplets, are rigidly fixed in the cytoplasm, and the force holding mitochondria is equal to the force produced by the microtubule-associated motors. Taking into account the characteristic of the centrifugal saltations, we suggest that they are mediated by an unusual dynein.

Animals↗

Traffic-related air pollutants induce the release of allergen-containing cytoplasmic granules from grass pollen.

BACKGROUND/AIM: Pollen cytoplasmic granules (PCG) are loaded with allergens. They are released from grass pollen grains following contact with water and can form a respirable allergenic aerosol. On the other hand, the traffic-related air pollutants NO2 and O3 are known to be involved in the current increase in the prevalence of allergic diseases via their adjuvant effects. Our objective was to determine the effects of air pollutants on the release of PCG from Phleum pratense (timothy grass) pollen. METHODS: P. pratense pollen was exposed to several concentrations of NO2 and O3. The induced morphological damages were observed by environmental scanning electron microscopy, and the amount of PCG released from the pollen upon contact with water was measured. RESULTS: The percentages of damaged grain were 6.4% in air-treated controls, 15% after treatment with the highest NO2 dose (50 ppm) and 13.5% after exposure to 0.5 ppm O3. In treated samples, a fraction of the grains spontaneously released their PCG. Upon subsequent contact with water, the remaining intact grains released more PCG than pollen exposed to air only. CONCLUSIONS: Traffic-related pollutants can trigger the release of allergen-containing granules from grass pollen, and increase the bioavailability of airborne pollen allergens. This is a new mechanism by which air pollution concurs with the current increase in the prevalence of allergic diseases.

Air Pollutants↗

Ultrastructural localization of cationic proteins in cytoplasmic granules of chicken and rabbit polymorphonuclear leukocytes.

Cytoplasmic granules known to contain cationic arginine-rich proteins can be identified by the ammoniacal silver reaction (ASR) which provides a cytochemical marker detectable under the electron microscope. Only the large rod-shaped granules of the chicken polymorphonuclear leukocytes (heterophils) and the large spherical azurophilic granules of the rabbit neutrophilic polymorphonuclear leukocytes show the ASR product as a discrete particulate electron-dense deposit. The other smaller granules are devoid of reaction product, as are membranes and mitochondria. The intracellular localization of the ASR product, as are membranes and mitochondria. The intracellular localization of the ASR product on the large granules coincides with the ASR product localization on the same isolated granule populations, when the ammoniacal silver reaction is applied to these granules after their separation by sucrose-density gradients. The cationic proteins may have intraleukocytic bacteriolytic properties, since ASR product, presumably indicating cationic protein from discharged granules, appears to surround ingested bacteria within cytoplasmic phagosomes.

Ammonia↗

The major component of Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific proteases in cytoplasmic granules of murine intraepithelial lymphocytes is granzyme A.

Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific proteases in cytoplasmic granules of intraepithelial lymphocytes in the murine intestine (iIEL) were characterized. BLT-specific proteases were isolated with the Sephacryl S-200 column chromatography, and the sample isolated contained a protein with a molecular weight of 58 kDa. The 58 kDa protein consisted of the homodimer of the 30 kDa subunits. The 58 kDa protease was detected by [3H] diisopropylfluorophosphate (DFP)-labeling, and also detectable by the immunoblotting using an antibody against the partial synthetic peptide of granzyme A. The cytoplasmic granules of iIEL were stained positively by an immunofluorescence with anti-granzyme A antibody. Therefore, it was suggested that the major BLT-specific proteases present in cytoplasmic granules of iIEL might be granzyme A.

Animals↗

Combinatorial SNARE complexes modulate the secretion of cytoplasmic granules in human neutrophils.

Mobilization of human neutrophil granules is critical for the innate immune response against infection and for the outburst of inflammation. Human neutrophil-specific and tertiary granules are readily exocytosed upon cell activation, whereas azurophilic granules are mainly mobilized to the phagosome. These cytoplasmic granules appear to be under differential secretory control. In this study, we show that combinatorial soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes with vesicle-associated membrane proteins (VAMPs), 23-kDa synaptosome-associated protein (SNAP-23), and syntaxin 4 underlie the differential mobilization of granules in human neutrophils. Specific and tertiary granules contained VAMP-1, VAMP-2, and SNAP-23, whereas the azurophilic granule membranes were enriched in VAMP-1 and VAMP-7. Ultrastructural, coimmunoprecipitation, and functional assays showed that SNARE complexes containing VAMP-1, VAMP-2, and SNAP-23 mediated the rapid exocytosis of specific/tertiary granules, whereas VAMP-1 and VAMP-7 mainly regulated the secretion of azurophilic granules. Plasma membrane syntaxin 4 acted as a general target SNARE for the secretion of the distinct granule populations. These data indicate that at least two SNARE complexes, made up of syntaxin 4/SNAP-23/VAMP-1 and syntaxin 4/SNAP-23/VAMP-2, are involved in the exocytosis of specific and tertiary granules, whereas interactions between syntaxin 4 and VAMP-1/VAMP-7 are involved in the exocytosis of azurophilic granules. Our data indicate that quantitative and qualitative differences in SNARE complex formation lead to the differential mobilization of the distinct cytoplasmic granules in human neutrophils, and a higher capability to form diverse SNARE complexes renders specific/tertiary granules prone to exocytosis.

Cell Differentiation↗

Lymphokine-activated killer cells induced in vivo in mice showing IL-2 toxicity have cytoplasmic granules containing perforin and its hemolytic activity.

Cytoplasmic granules of LAK cells isolated from mice showing side effects of recombinant human IL-2 (rhIL-2) display BLT-serine esterase activity and calcium-dependent hemolytic activity and seem to be involved in the mechanisms of LAK cell-mediated rhIL-2 toxicity. In this report, the hemolytically active substance was partially purified from the LAK granules and shown to be mouse perforin. Mice were implanted with miniosmotic pumps filled with a dose of rhIL-2 that induced known toxicity. The LAK granules were isolated from LAK cell-rich subcutaneous tissue around the infusion sites. The hemolytically active substance in the granule preparation was solubilized by 2 M NaCl and passed through a butyl Sepharose column and then a DEAE Toyopearl column. In immunoblotting, the hemolytically active fractions reacted with an anti-mouse perforin mAb and the reaction depended on the activity. The molecular sizes of the perforin-positive bands were 66 kDa and 51 kDa under reducing and nonreducing conditions, respectively. These results confirmed the existence of mouse perforin and its hemolytic activity in the LAK granules of rhIL-2-treated mice, as has been shown for granules of cytotoxic T or NK cell clones in vitro.

Animals↗

Amoebapores, a family of membranolytic peptides from cytoplasmic granules of Entamoeba histolytica: isolation, primary structure, and pore formation in bacterial cytoplasmic membranes.

Three peptides with pore-forming activity were isolated from the cytoplasmic granules of pathogenic Entamoeba histolytica by acidic extraction, gel filtration and reversed-phase high-performance liquid chromatography. Partial amino acid sequence analysis of the three active peptides revealed that the most abundant of them was amoebapore and the other two were isoforms thereof. Cloning and sequencing of genomic DNA resolved the amino acid sequence of the two newly recognized peptides. The three peptides designated amoebapores A, B and C were found to have the same molecular size but to differ markedly in their primary structure, although all six cysteine residues are conserved. Despite sequence divergence, structural implications predict for the three peptides a similar amphipathic alpha-helical conformation stabilized by disulphide bonds. All three isoforms exhibit pore-forming activity toward lipid vesicles, but they differ in their kinetics. They also are capable of perturbing the integrity of bacterial cytoplasmic membranes and thereby kill Gram-positive bacteria. The amoebapores represent a distinct family of membrane-active peptides that may function intracellularly as antimicrobial agents but may also confer cytolytic activity on the parasite.

Amino Acid Sequence↗

Effect of chloroquine on morphology of cytoplasmic granules in maturing human leukocytes--an ultrastructural study.

Bone marrow and peripheral blood from patients who had received chloroquine phosphate were studied to determine the effect of this drug on the ultrastructure of cytoplasmic granules in leukocytes. Neutrophils from approximately one-half of the patients who were treated developed abnormal cytoplasmic granules. Vacuolar, lamellar, and particulate components within abnormal, large granules were present in myelocytes from certain patients who received chloroquine therapy. Mature neutrophils and lymphocytes from these patients showed variable numbers of large, membrane-bounded structures containing myelin figures. Cytoplasmic granules in eosinophilic myelocytes from patients treated with chloroquine did not contain the usual crystalloid structure, but instead contained small whorls of osmiophilic material. The granules in abnormal mature eosinophils were replaced by large vacuoles which contained amorphous material. The abnormal granules seen in these various white cells after chloroquine therapy may either reflect defective granule formation or autophagy.

Chloroquine↗

Giant cytoplasmic granules in Langerhans cells of Chediak-Higashi syndrome.

Giant membrane-bound cytoplasmic granules were found in the epidermal Langerhans cells of a patient with the Chediak-Higashi syndrome. These cells also contained normal-appearing Birbeck granules. The giant granules had a granular or sometimes globular internal structure; they are believed to derive from fusion of lysosomes or some portion of Birbeck granules. It is unclear whether this morphologic change in Langerhans cell interferes with their antigen-presenting function; it may be, in part, responsible for the frequent infections seen in patients with Chediak-Higashi syndrome that are otherwise more clearly related to the abnormalities in neutrophils and lymphocytes. The Langerhans cell is another cellular type in Chediak-Higashi syndrome in which giant cytoplasmic granules are found.

Biopsy↗