In vitro study of the phagocytic processes in splenic granulocytes of the tench (Tinca tinca, L.).

The different stages of the phagocytic process by splenic granulocytes of Tinca tinca were studied. Adherence capacity to both endothelium and tissue substrate, mobility rate, the phagocytosis capacity for both cells (Candida albicans) and inert particles (latex beads), candidicide power, and capacity of digestion measured by nitroblue tetrazolium (NBT) reduction were evaluated in splenic granulocytes of healthy adult tench. The capacity of adherence to nylon fiber was possessed by 51% of the granulocytes. The percentage capable of adherence to smooth plastic surfaces rose with incubation time. Casein, an effective chemoattractant, increased the random mobility of the granulocytes. Phagocytosis was greater for opsonized C. albicans than for nonopsonized. However, the number of phagocytosed yeast cells destroyed by the granulocytes did not depend on whether or not the C. albicans had been previously opsonized. The phagocytosis indices and the percent phagocytosis of latex beads were greater than those obtained for the phagocytosis of C. albicans in the absence of serum. Finally, the metabolic activity in these cells following the digestion of ingested material showed a 148 ± 31% stimulation. The results show that splenic cells of tench have the capacity to make a phagocytic response against both cells (C. albicans) and inert particles (latex beads).     

Redistribution of ecto-5'-nucleotidase during phagocytosis by guinea pig polymorphonuclear leukocytes

We demonstrate that 5'-nucleotidase (5'NT), an ectoenzyme of guinea pig polymorphonuclear leukocytes, is largely excluded from phagosomal membrane, rather than internalized randomly during phagocytosis of heat-killed bacteria, latex microbeads, or zymosan particles. Cells were fixed in 0.25% glutaraldehyde (pH 6.3) at 4 degrees C for 10 min and incubated in a cytochemical medium for the demonstration of 5'NT. In the nonphagocytosing cells, 5'NT was evenly distributed on the external side of the plasma membrane. In cells phagocytosing bacteria, 5'NT appeared to be cleared from the nascent phagosomal membrane; after 5 min of phagocytosis, most of the phagocytic vacuoles containing bacteria, latex, or zymosan particles were devoid of reaction product. When phagosomes containing latex particles were isolated and biochemically assayed, they contained less than 3% of the total cellular 5'NT activity even after 60 min of phagocytosis, and at that time the total cellular 5'NT activity had not declined. When the diazonium salt of sulfanilic acid (DASA), a nonpermeable ectoenzyme inhibitor, was used to determine the distribution of extracellular and intracellular 5'NT activity, no increase in DASA-insensitive intracellular 5'NT was found after phagocytosis of latex or opsonized zymosan. Cytochemical and biochemical evidence led us to conclude that 5'NT is excluded from phagosomal membrane, and that the exclusion is due to redistribution rather than to inactivation by granule enzymes.     

Treponema denticola outer membrane enhances the phagocytosis of collagen-coated beads by gingival fibroblasts

Human gingival fibroblasts (HGFs) degrade collagen fibrils in physiological processes by phagocytosis. Since Treponema denticola outer membrane (OM) extract perturbs actin filaments, important structures in phagocytosis, we determined whether the OM affects collagen phagocytosis in vitro by HGFs. Phagocytosis was measured by flow cytometric assessment of internalized collagen-coated fluorescent latex beads. Confluent HGFs pretreated with T. denticola ATCC 35405 OM exhibited an increase in the percentage of collagen phagocytic cells (phagocytosis index [PI]) and in the number of beads per phagocytosing cell (phagocytic capacity [PC]) compared with untreated controls. The enhancement was swift (within 15 min) and was still evident after 1 day. PI and PC of HGFs for bovine serum albumin (BSA)-coated beads were also increased, indicating a global increase in phagocytic processes. These results contrasted those for control OM from Veillonella atypica ATCC 17744, which decreased phagocytosis. The T. denticola OM-induced increase in bead uptake was eliminated by heating the OM and by depolymerization of actin filaments by cytochalasin D treatment of HGFs. Fluid-phase accumulation of lucifer yellow was enhanced in a saturable, concentration-dependent, transient manner by the T. denticola OM. Our findings were not due to HGF detachment or cytotoxicity in response to the T. denticola OM treatment since the HGFs exhibited minimal detachment from the substratum; they did not take up propidium iodide; and there was no change in their size, granularity, or content of sub-G1 DNA. We conclude that a heat-sensitive component(s) in T. denticola OM extract stimulates collagen phagocytosis and other endocytic processes such as nonspecific phagocytosis and pinocytosis by HGFs.     

A Role for Anti-Inflammatory Agents and Cyclic Amp in Regulating Fibronectin-Mediated Phagocytosis

The present study deals with the effects of anti-inflammatory drugs and agents known to elevate intracellular levels of cyclic AMP (cAMP) on plasma fibronectin-mediated (PFn) phagocytosis of radiolabeled, gelatin-coated latex particles (g-Ltx*) by inflammatory macrophages. Monolayers of casein-elicited peritoneal macrophages were preincubated with the specified agents for either 1 or 24 hrs at 37°C prior to the measurements of phagocytosis in the presence of human plasma fibronectin (47 ug/ml) and heparin (6.7 U/ml).

Under these conditions, prostaglandin E₁, colchicine, vincristine, and cytochalasin B were all effective in inhibiting g-Ltx* phagocytosis by macrophages in a dose-dependent fashion. More potent inhibition of phagocytosis was manifested by agents known to increase intracellular levels of cAMP in phagocytic cells. Dibutyryl cyclic AMP (dbcAMP), d, 1-isoproterenol and aminophylline (10^--⁵ to 10^--³M) were all effective in reducing the uptake of g-Ltx* by macrophages. The combination of dbcAMP and aminophylline acted additively. These studies demonstrate that anti-inflammatory drugs and cAMP-elevating agents exert potent inhibitory effects on fibronectin-mediated phagocytosis of gelatin-coated particles by macrophages. Thus, our system provides a suitable in vitro model for further investigations into the humoral regulation of pnagocytosis of denatured collagen-coated particles and tissue debris by inflammatory phagocytic cells.     

Effects of macrophage culture supernatants (monokines) on phagocytosis,catabolism, lysosomal enzymes and cyclic amp of isologous macrophages

Monokines (48 h-culture supernatants) obtained from resting mouse peritoneal macrophages were found to modify various fundamental functions of newly prepared isologous target macrophages. Thus, the cellular level of cyclic AMP showed a rapid though transient increase, whereas the release of a lysosomal marker enzyme (β-glucuronidase), phagocytosis and catabolism of endocytosed particles were all inhibited. Inhibition was dose-dependent but the various functional parameters studied showed important individual differences in responsiveness: release of β-glucuronidase > phagocytosis of zymosan and sheep erythrocytes > catabolism of endocytosed sheep erythrocytes. Neither the release of monokines nor the expression of their effects required the presence of serum in culture medium or that of lymphocytes in macrophage suspensions and in no case could these effects be attributed to cytotoxicity or to the presence of breakdown products from lyzed cells.Monokines obtained from phagocytosing macrophages after 4 h incubation had inhibitory effects similar to those of the standard 48 h preparations.     

Reactive-oxygen formation and its relationship to prostaglandin and cyclic AMP production by zymosan-treated rat peritoneal macrophages

Addition of zymosan (20 particles/cell) to suspensions of resident rat peritoneal macrophages caused an increase in the concns of prostaglandins and cyclic AMP. Preincubation of the cells with inhibitors of arachidonate metabolism led to inhibition of prostaglandin, but not of cyclic AMP, formation, which suggested that the two processes may occur independently of each other in phagocytosing cells. The luminol-dependent chemiluminescence associated with the addition of zymosan to the cells consisted of a minor, Ca²⁺-dependent, glucose-independent component and a major, glucose-dependent, Ca²⁺-independent component. Only the minor, Ca²⁺-dependent component appeared to be related to the lipoxygenation of arachidonic acid. Close examination of the production of prostaglandins and cyclic AMP and of chemiluminescence after zymosan addition, indicated that the expanded pool of endogenous cyclic AMP was probably not a negative modulator of the other two processes, although they remained susceptible to inhibition by exogenously-added cyclic AMP analogues or PGE₂, The events induced by zymosan may be relevant to the physiological roles of prostaglandins during the inflammatory response.     

Prostaglandin E2 enhances axonal transport and neuritogenesis in cultured mouse dorsal root ganglion neurons

The effects of prostaglandin E₂ on axonal transport in cultured mouse dorsal root ganglion neurons were investigated by analysing the number of axonally transported particles under video-enhanced microscopy. Application of prostaglandin E₂ increased the number of particles transported in anterograde and retrograde directions. The EP₂ prostaglandin receptor agonist butaprost mimicked the effect of prostaglandin E₂, but the EP₁/EP₃ prostaglandin receptor agonist 17-phenyl trinor prostaglandin E₂ and the EP₃ prostaglandin receptor agonist M&B 28767 had no effect. The membrane-permeable cyclic AMP analogue dibutyryl cyclic AMP and the adenylate cyclase activator forskolin mimicked the effect of prostaglandin E₂. The protein kinase A inhibitor H-89 reversibly reduced the number of particles in both anterograde and retrograde directions. The effects of prostaglandin E₂ and dibutyryl cyclic AMP were blocked by H-89. Taken together with previous biochemical studies showing that prostaglandin E₂ increases cyclic AMP levels, the present results suggest that prostaglandin E₂ enhances axonal transport via the EP₂ receptor and cyclic AMP-dependent protein kinase A pathway. We further investigated the role of prostaglandin E₂ in neurite growth. Prostaglandin E₂ increased both the number of cells exhibiting neurites and the neurite growth rate, operating by a similar mechanism to stimulation of axonal transport.Prostaglandin E₂ may modulate axonal transport to supply materials for morphogenesis as well as other functions in sensory neurons.     

Actions of histamine, secretin, and PGE2 on cyclic AMP production by isolated canine fundic mucosal cells.

Cyclic AMP production was studied in isolated canine fundic gastric mucosal cells. Histamine, prostaglandin E2 (PGE2), and secretin increased cyclic AMP production by unenriched mucosal cells. In separated cell fractions, histamine stimulation of cyclic AMP production correlated with the parietal cell content of the fractions. Secretin in concentrations above 1 nM stimulated cyclic AMP production, and this effect correlated with the pepsinogen content of the separated cell fractions. At concentrations above 1 microM, PGE2 stimulated cyclic AMP production; this effect was found in all separated cell fractions and was not associated with any of the available cell markers. PGE2 stimulation of cyclic AMP production was, however, negatively correlated with the parietal cell content. Thus, histamine stimulated cyclic AMP production by parietal cells and secretin stimulated production of cyclic AMP by chief cells. PGE2 stimulation of cyclic AMP production could not be localized to a single cell type but occurred primarily in nonparietal cells.     

Modulatory role of cyclic AMP in the release of platelet-activating factor from human polymorphonuclear leucocytes.

Zymosan coated with complement (Zc) was observed to induce a transient elevation of the intracellular cyclic AMP in human polymorphonuclear cells: a two- to three-fold increase was observed within 1 min after stimulation and approached prestimulation levels by 2 min incubation. These changes in cyclic AMP were not associated with significant changes in cyclic GMP levels. Zymosan caused the release of PAF and beta-glucuronidase and particle uptake, which was initiated about 5 min after stimulation. These results suggest that the transient increase in cyclic AMP content might regulate an early event during mediator release. In an attempt to study further the significance of this rise in cyclic AMP, cells were preincubated with various phosphodiesterase inhibitors. Preincubation of the cells with methylisobutylxanthine (MIX, 10(-6) M to 5 X 10(-5) M), theophylline (3 X 10(-5) to 3 X 10(-3) M) or dipyridamole (10(-6) M to 10(-4) M) enhanced the increase in cyclic AMP levels, but resulted in dose-dependent inhibition of Zc-induced mediator release. Particle uptake and beta-glucuronidase release were less sensitive than PAF release to phosphodiesterase inhibitors, which argues in favour of the independence of both phenomena. Synergistic experiments with MIX and cyclic AMP indicate that the effect of this drug is through its action on cyclic AMP levels. These results suggest that while Zc-induced cyclic AMP elevation might occur in an intracellular place critical to its effect; phosphodiesterase inhibitors may elevate cyclic AMP levels throughout the cell and therefore inhibit the biological response.     

An improved method to quantitate phagocytosis with mineral oil particles which avoid cell flotation

We have shown that actively phagocytosing human polymorphonuclear leukocytes (PMN) float on top of the incubation medium when Oil Red O containing paraffin oil particles (density 0.8740) are used as the phagocytosable material. This implies that the quantitation of phagocytosis based on the recovery of Oil Red O in phagocytosing cells pelleted after centrifugation would be underestimated. We therefore prepared particles of progressively increasing density by mixing paraffin oil (density 0.8740) with silicon oil (density 1.0802). Cell flotation also occurred with paraffin oil-silicon oil particles and could be avoided only when the density of the particles used had reached 0.9952 g/cm3. Paraffin oil-silicon oil particles of a density sufficient to dissolve the dye Oil Red O were therefore used to quantitate both the initial rate of phagocytosis and the phagocytic capacity of human PMN. With this assay the initial rate of phagocytosis was found to be 400 micrograms paraffin oil-silicon oil/min/5 X 10(6) PMN, which is about 20 times higher than that reported for the same cell type using paraffin oil particles. The calculated maximum phagocytic capacity was 2.5 mg paraffin oil-silicon oil/5 X 10(6) PMN. The uptake of paraffin oil-silicon oil particles was sensitive to inhibitors of phagocytosis, such as N-ethylmaleimide, papaverine and cytochalasin B, in a dose dependent manner. The assay also permitted the detection of increased phagocytosis such as occurs in myeloperoxidase deficient PMN.     

Stimulation of the phagocytic function in guinea pig peritoneal macrophages by physical activity stress

Summary A study was made of all the different stages of the phagocytic function in peritoneal macrophages from male guinea pigs [3 (SD 1) months old] before, immediately after, and 24 h after being subjected to stress from physical activity (swimming until exhaustion). The early (10 min) and late (40 min) adherence to tissue substrates, chemotaxis, attachment and phagocytosis ofCandida albicans, ingestion of inert particles (latex beads), and basal oxidative metabolism [measured by nitroblue tetrazolium (NBT) reduction] were significantly stimulated by the physical activity. After 24 h, late adherence, attachment capacities, and basal oxidative metabolism returned to basal values, whereas early adherence, chemotaxis, phagocytosis of cells and inert particles, and microbicidal capacity (production of superoxide anion measured by NBT reduction in presence of ingested material) remained significantly increased. The stress produced by physical activity, reflected in increased serum corticosterone values, led to a global stimulation of the phagocytic function.     

Role of protein kinase C in hydroxyapatite- induced phagocytosis by a murine macrophage cell line (RAW264.7)

The role of protein kinase C (PKC) in hydroxyapatite (HA)-induced phagocytosis by RAW 264.7 cells was investigated. The cells were incubated with HA particles at various incubation time and the levels of PKC activity were determined from the cell lysate. To determine the role of PKC, particles were incubated with the cells pretreated with the various concentrations of bisindolylmaleimide, a PKC inhibitor, and phagocytosis was then assessed at 60 min. Latex beads were used as a control. Our results showed that following incubation with HA particles, the levels of PKC activity in RAW264.7 cells was highest at 7 min and then decreased to reach the baseline levels of the controls at 30 min. Pretreatment of the cells with bisindolylmaleimide significantly reduced phagocytosis of HA particles in a dose-dependent pattern. The results of our present study suggest therefore that ingestion of HA by RAW264.7 cells may depend on PKC activity that may act in the early stages of phagocytosis.     

A new simple fluorometric assay for phagocytosis

A highly sensitive, but simple and quantitative, fluorometric assay method for phagocytosis by cells such as macrophages and polymorphonuclear leukocytes was developed by utilizing fluorescent particles. Escherichia coli, Serratia marcescens, yeast, and latex particles were conjugated with fluorescein isothiocyanate and used as fluorescent particles. The assay procedure requires phagocytic cells, appropriate medium, fluorescent particles, sodium dodecyl sulfate, microtiter culture plate (24 wells), clinical centrifuge, and fluorescence spectrophotometer. One hundred assays can be done within 30 min after the incubation period. A time course analysis with this method showed that the phagocytosis of all these particles was dependent on temperature, and that the number of particles ingested by cells increased rapidly during the initial 30 min of incubation at 37 degrees C. Free fluorescent particles can be removed effectively by aspiration from the well. At 0 degree C, very few particles were ingested by cells or adsorbed onto the phagocytic cell surface as confirmed by fluorescence microscopy. An inhibitory effect of cepharanthin and sodium azide on phagocytosis was also confirmed by this method. The differential susceptibility of E. coli B and S. marcescens to phagocytosis also could be determined by this method.     

Cyclic AMP in macrophages from experimental granulomas and the effect of prostaglandin E2

Leucocytes were isolated by pronase digestion from granuloma tissue at different stages of inflammation induced by carrageenin-soaked sponge implants in rats and cyclic AMP was measured in these cells. In a mixed cell suspension, containing granulocytes and macrophages, the cyclic AMP levels increased during the early stages of inflammation but decreased when the granuloma became established. However, after correction for the proportion of infiltrating macrophages, as the inflammation progressed only a fall in cyclic AMP content was observable. Exposure of granuloma-derived cells to PGE₂ resulted in a rise in cyclic AMP content, which was more pronounced in cells isolated during a later rather than an earlier stage of granuloma development. The results provide support for the earlier proposal that the anti-inflammatory effect of E-type prostaglandins on granulomas is partially explicable on the basis of cyclic AMP changes in infiltrating macrophages.     

Cyclic AMP formation during phagocytosis

The content of cyclic adenosine-3, 5-monophosphate (AMP) in phagocytic macrophages was shown to be increased especially during phagocytosis of the living microbes. The cyclic AMP formed during phagocytosis could be detected in the incubation medium, but in the cells it remained at almost the same level. The cyclic AMP concentration in cells of the intestinal mucosa and in the blood serum of germfree guinea pigs also was increased after injection ofEscherichia coli 055 cells; this points to the participation of the adenylate cyclase system in interaction between microorganisms and the epithelium of the small intestine.Research Laboratory of Experimental Biological Models, Academy of Medical Sciences of the USSR. Institute of Biological and Medical Chemistry, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR, V. N. Orekhovich.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 82, No. 8, pp. 953–956, August, 1976.     

Prostaglandin E(2) enhances axonal transport and neuritogenesis in cultured mouse dorsal root ganglion neurons

The effects of prostaglandin E₂ on axonal transport in cultured mouse dorsal root ganglion neurons were investigated by analysing the number of axonally transported particles under video-enhanced microscopy. Application of prostaglandin E₂ increased the number of particles transported in anterograde and retrograde directions. The EP₂ prostaglandin receptor agonist butaprost mimicked the effect of prostaglandin E₂, but the EP₁/EP₃ prostaglandin receptor agonist 17-phenyl trinor prostaglandin E₂ and the EP₃ prostaglandin receptor agonist M&B 28767 had no effect. The membrane-permeable cyclic AMP analogue dibutyryl cyclic AMP and the adenylate cyclase activator forskolin mimicked the effect of prostaglandin E₂. The protein kinase A inhibitor H-89 reversibly reduced the number of particles in both anterograde and retrograde directions. The effects of prostaglandin E₂ and dibutyryl cyclic AMP were blocked by H-89. Taken together with previous biochemical studies showing that prostaglandin E₂ increases cyclic AMP levels, the present results suggest that prostaglandin E₂ enhances axonal transport via the EP₂ receptor and cyclic AMP-dependent protein kinase A pathway. We further investigated the role of prostaglandin E₂ in neurite growth. Prostaglandin E₂ increased both the number of cells exhibiting neurites and the neurite growth rate, operating by a similar mechanism to stimulation of axonal transport.

Prostaglandin E₂ may modulate axonal transport to supply materials for morphogenesis as well as other functions in sensory neurons.     

Effect of deuterium oxide on neutrophil oxidative metabolism,phagocytosis, and lysosomal enzyme release

We have previously shown that deuterium oxide (D₂O) enhances the oxidation of methionine, a myeloperoxidase (MPO)-mediated reaction, by human neutrophils during phagocytosis. However, D₂O has no effect on the oxidation of methionine by the purified MPO-H₂O₂-Cl^– system. To explain this observation, we studied the effect of D₂O on the oxidative metabolism, phagocytosis, and lysosomal enzyme release by human neutrophils. D₂O stimulated the hexose monophosphate shunt (HMS) activity of resting neutrophils in a dose-response fashion. In the presence of latex particles or phorbol myristate acetate (PMA), D₂O brought about an exaggerated stimulation of the HMS activity. This enhancement of the HMS activity by D₂O was markedly reduced when neutrophils form two patients with X-linked chronic granulomatous disease (CGD) were used, either in the presence or absence of latex particles or PMA. Superoxide and H₂O₂ production by neutrophils in the presence of latex particles or PMA were also stimulated by D₂O. In contrast, D₂O inhibited the ingestion of latex particles. D₂O enhanced the extracellular release of MPO, but not lactate dehydrogenase, by neutrophils only in the simultaneous presence of cytochalasin B and latex particles. The enhancement of HMS activity and MPO release by D₂O was partially inhibited by colchicine. Our results suggest that enhancement of neutrophil oxidative metabolism by D₂O may in part explain the stimulation of methionine oxidation by phagocytosing neutrophils.     

Hemocytes from the tobacco hornworm Manduca sexta have distinct functions in phagocytosis of foreign particles and self dead cells

Phagocytosis is an important innate immune response against microbial infections and an effective mechanism to eliminate apoptotic cells. In vertebrates, phagocytes such as macrophages and dendritic cells are involved in phagocytosis. We demonstrate here that insect hemocytes have distinct functions in phagocytosis of foreign particles and self dead cells. Plasmatocytes from the tobacco hornworm Manduca sexta were major hemocytes involved in phagocytosis of non-self microsphere beads, whereas granulocytes were apparently the only hemocytes that phagocytose self dead cells. We also showed that M. sexta immulectin-2, a pattern recognition receptor that protects larvae from bacterial infection, has an opsonic activity in phagocytosis. Immulectin-2 bound to the surface of granulocytes from the na?ve larvae, but more immulectin-2 bound to plasmatocytes when larvae were injected with microsphere beads. Coupling of immulectin-2 onto microsphere beads enhanced in vitro phagocytosis of the beads. Our results suggest that insect hemocytes can have specialized functions similar to vertebrate phagocytes in phagocytosis, and pattern recognition receptors may function as opsonins to enhance phagocytosis.     

The role of cyclic 3',5'-adenosine monophosphate (cyclic AMP) in the ability of sympathetic nerve stimulation to enhance growth and secretion in rat salivary glands in vivo.

1. The cyclic AMP content of the rat salivary glands was measured after sympathetic and parasympathetic nerve stimulation, and after the administration of isoprenaline and phenylephrine. 2. Stimulation of the sympathetic nerves (20 Hz, 1 msec supramaximal voltage for 30 sec of every min) initially raised the cyclic AMP level in both the parotid and submaxillary glands. The rise, which was blocked by propranolol, was not maintained and declined during stimulation from the maximum (reached after 3 min stimulation) to control levels after approximately 15 min. Stimulation of the parasympathetic nerves for 5 min did not raise the cyclic AMP levels. 3. Isoprenaline and phenylephrine raised the cyclic AMP level in both glands. 4. Theophylline enhanced the growth of the parotid and submaxillary glands as measured either by an increase in the wet and dry weights or in acinar axes lengths. N6O2-dibutyryl cyclic monophosphoric acid (dibutyryl cyclic AMP), did not enhance the growth of the glands. 5. It is concluded that cyclic AMP does not directly control cell growth in the rat salivary glands but may be a 'trigger' for events leading eventually to increased growth.     

CD44介导的透明质酸促进巨噬细胞的吞噬功能

目的研究透明质酸（HA）对巨噬细胞吞噬功能的影响及其机制.方法用免疫细胞化学法标记CD44.在噬动轨迹实验中,用图像分析仪测量细胞吞噬后在其周围形成的无颗粒区面积,扫描电镜下观察巨噬细胞形态.在吞噬荧光微珠实验中,计数吞噬的微珠,观察细胞内F-肌动蛋白的分布.在吞噬HA包被微珠实验中,计数吞噬的微珠,在扫描电镜下观察细胞形态,用激光扫描共焦显微镜分析吞噬HA包被微珠时细胞内Ca^2＋水平.用CD44阻断抗体处理后,观察细胞吞噬功能的变化.结果巨噬细胞表达CD44.吞噬细胞较圆,板状伪足和丝状伪足较短.在吞噬颗粒和微珠时,细胞膜出现杯状凹陷.在HA组,吞噬氯化金颗粒和荧光微珠的数目增多,吞噬荧光微珠处的F-肌动蛋白丰富.在包被HA微珠组,吞噬微珠的数目增多,吞噬处的Ca^2＋水平显著升高.阻断CD44后,细胞吞噬氯化金颗粒、荧光微珠和HA包被微珠减少.结论HA促进巨噬细胞的吞噬功能,CD44介导HA对巨噬细胞吞噬功能的作用.