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Fulltext Antibodies in children with malaria to PfEMP1, RIFIN and SURFIN expressed at the Plasmodium falciparum parasitized red blood cell surface

Quintana MDP, Ch'ng JH, Moll K, Zandian A, Nilsson P, Idris ZM, et al.

Sci Rep, 2018 02 19;8(1):3262.
PMID: 29459776 DOI: 10.1038/s41598-018-21026-4

Naturally acquired antibodies to proteins expressed on the Plasmodium falciparum parasitized red blood cell (pRBC) surface steer the course of a malaria infection by reducing sequestration and stimulating phagocytosis of pRBC. Here we have studied a selection of proteins representing three different parasite gene families employing a well-characterized parasite with a severe malaria phenotype (FCR3S1.2). The presence of naturally acquired antibodies, impact on rosetting rate, surface reactivity and opsonization for phagocytosis in relation to different blood groups of the ABO system were assessed in a set of sera from children with mild or complicated malaria from an endemic area. We show that the naturally acquired immune responses, developed during malaria natural infection, have limited access to the pRBCs inside a blood group A rosette. The data also indicate that SURFIN4.2 may have a function at the pRBC surface, particularly during rosette formation, this role however needs to be further validated. Our results also indicate epitopes differentially recognized by rosette-disrupting antibodies on a peptide array. Antibodies towards parasite-derived proteins such as PfEMP1, RIFIN and SURFIN in combination with host factors, essentially the ABO blood group of a malaria patient, are suggested to determine the outcome of a malaria infection.

Matched MeSH terms: Phagocytosis
Fulltext The role of cells, neurotrophins, extracellular matrix and cell surface molecules in peripheral nerve regeneration

Naidu M

Malays J Med Sci, 2009 Apr;16(2):10-4.
PMID: 22589652 MyJurnal

Wallerian degeneration is a complicated process whereby axons and myelin sheaths undergo degeneration, and eventually are phagocytosed by macrophages and Schwann cells following nerve damage. Schwann cells proliferate and the endoneural tubes persist. In addition, neurotrophins, neural cell adhesion molecules, cytokines and other soluble factors are upregulated to facilitate regeneration. The important role of cellular components, neurotrophins, and extracellular matrix components, including cell surface molecules involved in this regenerative process, is highlighted and discussed in this review.

Matched MeSH terms: Phagocytosis
Fulltext Antibody-dependent cellular phagocytosis of tropomyosin receptor kinase C (TrkC) expressing cancer cells for targeted immunotherapy

Lai PS, Usama SM, Kiew LV, Lee HB, Chung LY, Burgess K, et al.

Cancer Immunol Immunother, 2022 Sep;71(9):2099-2108.
PMID: 35032175 DOI: 10.1007/s00262-022-03147-y

Conventional cancer therapies such as chemotherapy are non-selective and induce immune system anergy, which lead to serious side effects and tumor relapse. It is a challenge to prime the body's immune system in the cancer-bearing subject to produce cancer antigen-targeting antibodies, as most tumor-associated antigens are expressed abundantly in cancer cells and some of normal cells. This study illustrates how hapten-based pre-immunization (for anti-hapten antibodies production) combined with cancer receptor labeling with hapten antigen constructs can elicit antibody-dependent cellular phagocytosis (ADCP). Thus, the hapten antigen 2,4-dinitrophenol (DNP) was covalently combined with a cancer receptor-binding dipeptide (IYIY) to form a dipeptide-hapten construct (IYIY-DNP, MW = 1322.33) that targets the tropomyosin receptor kinase C (TrkC)-expressed on the surface of metastatic cancer cells. IYIY-DNP facilitated selective association of RAW264.7 macrophages to the TrkC expressing 4T1 cancer cells in vitro, forming cell aggregates in the presence of anti-DNP antibodies, suggesting initiation of anti-DNP antibody-dependent cancer cell recognition of macrophages by the IYIY-DNP. In in vivo, IYIY-DNP at 10 mg/kg suppressed growth of 4T1 tumors in DNP-immunized BALB/c mice by 45% (p

Matched MeSH terms: Phagocytosis
Synthesis and evaluation of chalcone derivatives as inhibitors of neutrophils' chemotaxis, phagocytosis and production of reactive oxygen species

Bukhari SN, Tajuddin Y, Benedict VJ, Lam KW, Jantan I, Jalil J, et al.

Chem Biol Drug Des, 2014 Feb;83(2):198-206.
PMID: 24433224 DOI: 10.1111/cbdd.12226

Inhibitory effects on neutrophils' chemotaxis, phagocytosis and production of reactive oxygen species (ROS) are among the important targets in developing anti-inflammatory agents and immunosuppressants. Eight series of chalcone derivatives including five newly synthesized series were assessed for their inhibitory effects on chemotaxis, phagocytosis and ROS production in human polymorphonuclear neutrophils (PMNs). Inhibition of PMNs' chemotaxis and phagocytosis abilities were investigated using the Boyden chamber technique and the Phagotest kit, respectively, while ROS production was evaluated using luminol- and lucigenin-based chemiluminescence assay. The new derivatives (4d and 8d), which contain 4-methylaminoethanol functional group were active in all the assays performed. It was also observed that some of the compounds were active in inhibiting chemotaxis while others suppressed phagocytosis and ROS production. The information obtained gave new insight into chalcone derivatives with the potential to be developed as immunomodulators.

Matched MeSH terms: Phagocytosis/drug effects*
In-vitro phagocytosis and intracellular killing of Pasteurella multocida B:2 by phagocytic cells of buffaloes

Puspitasari Y, Annas S, Adza-Rina MN, Zamri-Saad M

Microb Pathog, 2019 Jun;131:170-174.
PMID: 30978429 DOI: 10.1016/j.micpath.2019.04.012

Pasteurella multocida B:2 is a Gram-negative organism causing haemorrhagic septicaemia (HS) in buffaloes. It causes severe pulmonary infection, leading to infiltration of numerous macrophages and neutrophils. Despite the inflammatory response, buffaloes succumb to HS. This study aims to evaluate the in-vitro efficacy of macrophages and neutrophils of buffalo following exposure to P. multocida B:2. In-vitro infections were done using 107 cfu/ml of P. multocida B:2 for Group 1, Escherichia coli for Group 2 and Mannhaemia haemolytica A:2 for Group 3 cells. The inoculated cell cultures were harvested at 0, 30, 60 and 120 min post-exposure and the phagocytic, killing and cell death rates were determined. Both phagocytosis and killing rates of all bacteria increased over time. Phagocytosis involved between 71% and 73% neutrophils and between 60% and 64% macrophages at 120 min. Killing rate of all bacteria involved between 76% and 79% for neutrophils and between 70% and 74% for macrophages at 120 min. Death rate of neutrophils ranged between 67% in Group 3, and 88% in Group 1 at 120 min, significantly (p  0.05) than Group 2. Similar pattern was observed for death rate of macrophages. The phagocytosis and killing rates of P. multocida B:2 were similar to other bacterial species used in this study but more neutrophils and macrophages were dead following infection by P. multocida B:2 than M. haemolytica A:2.

Matched MeSH terms: Phagocytosis*
Fulltext Phagocytic activity and pro-inflammatory cytokines production by the murine macrophage cell line J774A.1 stimulated by a recombinant BCG (rBCG) expressing the MSP1-C of Plasmodium falciparum

Rapeah S, Dhaniah M, Nurul AA, Norazmi MN

Trop Biomed, 2010 Dec;27(3):461-9.
PMID: 21399587 MyJurnal

Macrophages are involved in innate immunity against malaria due to their ability to phagocytose infected erythrocytes and produce inflammatory cytokines, which are important for controlling parasite growth during malaria infection. In this study, the ability of a recombinant BCG (rBCG) vaccine expressing the 19-kDa C-terminus of merozoite surface protein-1 (MSP1-C) of Plasmodium falciparum, to stimulate the phagocytic activity and secretion of pro-inflammatory cytokines by the macrophage cell line J774A.1 was measured at varying times. The results demonstrate the ability of the rBCG construct to activate the inflammatory action of macrophages, which is important as a first-line of defence in clearing malaria infections.

Matched MeSH terms: Phagocytosis*
3,5-Bis[4-(diethoxymethyl)benzylidene]-1-methyl-piperidin-4-one, a Novel Curcumin Analogue, Inhibits Cellular and Humoral Immune Responses in Male Balb/c Mice

Arshad L, Jantan I, Bukhari SNA, Fauzi MB

Curr Pharm Biotechnol, 2018;19(6):468-482.
PMID: 29968535 DOI: 10.2174/1389201019666180703092723

BACKGROUND: 3,5-Bis[4-(diethoxymethyl)benzylidene]-1-methyl-piperidin-4-one (BBP), a novel synthetic curcumin analogue has previously been shown to manifest potent immunosuppressive effects on the in vitro phagocytosis process of human neutrophils.
OBJECTIVE: In the present study, BBP was investigated for it's in vivo innate and adaptive immune responses mediated by different humoral and cellular immune factors.
METHODS: Male Balb/c mice were orally fed with BBP (5, 10 and 20 mg/kg) for a period of 14 days and immunized with sheep red blood cells (sRBC) on day 0 for the determination of adaptive responses. The effects of BBP on phagocytosis process of neutrophils isolated from blood of treated/untreated animals were determined. The ceruloplasmin and lysozyme serum levels and myeloperoxidase (MPO) plasma level were also monitored. The mechanism was further explored by assessing its effects on the proliferation of T and B lymphocytes, T-lymphocytes subsets CD4+ and CD8+ and on the secretion of Th1/Th2 cytokines as well as serum immunoglobulins (IgG, IgM) and delayed type hypersensitivity (DTH) reaction.
RESULTS: BBP showed a significant dose-dependent reduction on the migration of neutrophils, Mac-1 expression, phagocytic activity and reactive oxygen species (ROS) production. In comparison to the sensitized control group, a dose-dependent inhibition was observed on lymphocyte proliferation along with the downregulation of effector cells expression and release of cytokines. Moreover, a statistically significant decrease was perceived in serum levels of ceruloplasmin, lysozyme and immunoglobulins and MPO plasma level of BBP-treated mice. BBP also dose-dependently inhibited sheep red blood cells (sRBC)-induced swelling rate of mice paw in DTH.
CONCLUSION: These findings suggest the potential of BBP as a potent immunosuppressive agent.

Matched MeSH terms: Phagocytosis/drug effects
Fulltext Stimulatory effects of polysaccharide fraction from Solanum nigrum on RAW 264.7 murine macrophage cells

Razali FN, Ismail A, Abidin NZ, Shuib AS

PLoS One, 2014;9(10):e108988.
PMID: 25299340 DOI: 10.1371/journal.pone.0108988

The polysaccharide fraction from Solanum nigrum Linne has been shown to have antitumor activity by enhancing the CD4+/CD8+ ratio of the T-lymphocyte subpopulation. In this study, we analyzed a polysaccharide extract of S. nigrum to determine its modulating effects on RAW 264.7 murine macrophage cells since macrophages play a key role in inducing both innate and adaptive immune responses. Crude polysaccharide was extracted from the stem of S. nigrum and subjected to ion-exchange chromatography to partially purify the extract. Five polysaccharide fractions were then subjected to a cytotoxicity assay and a nitric oxide production assay. To further analyze the ability of the fractionated polysaccharide extract to activate macrophages, the phagocytosis activity and cytokine production were also measured. The polysaccharide fractions were not cytotoxic, but all of the fractions induced nitric oxide in RAW 264.7 cells. Of the five fractions tested, SN-ppF3 was the least toxic and also induced the greatest amount of nitric oxide, which was comparable to the inducible nitric oxide synthase expression detected in the cell lysate. This fraction also significantly induced phagocytosis activity and stimulated the production of tumor necrosis factor-α and interleukin-6. Our study showed that fraction SN-ppF3 could classically activate macrophages. Macrophage induction may be the manner in which polysaccharides from S. nigrum are able to prevent tumor growth.

Matched MeSH terms: Phagocytosis/drug effects
Fulltext 4,5,4'-Trihydroxychalcone, 8,8'-(ethene-1,2-diyl)-dinaphtalene-1,4,5-triol and rutin from Gynura segetum inhibit phagocytosis, lymphocyte proliferation, cytokine release and nitric oxide production from phagocytic cells

Yuandani, Jantan I, Husain K

BMC Complement Altern Med, 2017 Apr 11;17(1):211.
PMID: 28399868 DOI: 10.1186/s12906-017-1726-z

BACKGROUND: Gynura segetum is used traditionally to treat various ailments related to the immune system, which include cancer, inflammation, rheumatism, diabetes, hypertension, and viral infections but little studies have been carried out to validate their ethnopharmacological aspects. In this study the immunosuppressive effects of G. segetum and its constituents were investigated.
METHODS: Isolation of compounds from G. segetum leaves was conducted using vacuum liquid chromatography (VLC) and column chromatography (CC). Two new compounds, namely 4,5,4'-trihydroxychalcone and 8,8'-(ethene-1,2-diyl)-dinaphtalene-1,4,5-triol, together with stigmasterol and β-sitosterol were isolated from G. segetum methanol extract and their structures were determined spectroscopically. The presence of gallic acid and rutin in the extract was determined quantitatively by a validated HPLC method. G. segetum methanol extract and its constituents were investigated for their effects on chemotaxis, phagocytosis, β2 integrin (CD18) expression, and reactive oxygen species (ROS) of polymorphonuclear leukocytes (PMNs), lymphocytes proliferation, cytokine release and nitric oxide (NO) production of phagocytes.
RESULTS: All the samples significantly inhibited all the innate immune responses tested except CD 18 expression on surface of leukocytes. Among the samples, 8,8'-(ethene-1,2-diyl)-dinaphtalene-1,4,5-triol exhibited the strongest inhibitory on chemotaxis, phagocytosis, ROS and NO production. The compound exhibited exceptionally strong inhibitions on ROS and chemotaxis activities with IC50 values lower than the positive controls, aspirin and ibuprofen, respectively. 4,5,4'-Trihydroxychalcone revealed the strongest immunosuppressive activity on proliferation of lymphocytes (IC50 value of 1.52 μM) and on release of IL-1β (IC50 value of 6.69 μM). Meanwhile rutin was the most potent sample against release of TNF-α from monocytes (IC50, 16.96 μM).
CONCLUSION: The extract showed strong immunosuppressive effects on various components of the immune system and these activities were possibly contributed mainly by 4,5,4'-trihydroxychalcone, 8,8'-(ethene-1,2-diyl)-dinaphtalene-1,4,5-triol and rutin.

Matched MeSH terms: Phagocytosis/drug effects
Synthesis and effects of pyrazolines and isoxazoles on the phagocytic chemotaxis and release of reactive oxygen species by zymosan stimulated human neutrophils

Bukhari SN, Jantan I, Wai LK, Lajis NH, Abbas F, Jasamai M

Med Chem, 2013 Dec;9(8):1091-8.
PMID: 23092331

A series of novel isoxazole and pyrazoline derivatives has been synthesized and evaluated for their effects on the chemiluminescence and chemotactic activity of human phagocytes. Their effects on the chemotactic migration of isolated polymorphonuclear leukocytes (PMNs) and on the release of reactive oxygen species (ROS) during respiratory burst of human whole blood and PMNs were carried out using the Boyden chamber technique and luminol-based chemiluminescence assay, respectively. Of the compounds tested, compounds 8, 9, 11 and 12 exhibited higher inhibitory activity on the release of ROS (with IC50 values ranging from 5.6 to 8.4 μM) than acetylsalicylic acid (IC50 = 9.5 μ M). These compounds also showed strong inhibitory activity on the migration of PMNs with compound 8 exhibiting an IC50 value lower than that of ibuprofen. The results suggest that some of these isoxazole and pyrazoline derivatives have ability to modulate the innate immune response of phagocytes at different steps, indicating their potential as a source of new immunomodulatory agents.

Matched MeSH terms: Phagocytosis/drug effects
Role of nitric oxide in hydroxyapatite-induced phagocytosis by murine macrophage cell line (RAW264.7)

Gopinath VK, Musa M, Samsudin AR, Lalitha P, Sosroseno W

Arch Oral Biol, 2006 Apr;51(4):339-44.
PMID: 16214104

The aim of this study was to determine the role of nitric oxide (NO) in hydroxyapatite (HA)-induced phagocytosis by a murine macrophage cell line (RAW264.7). The cells were incubated with HA particles at various incubation time and phagocytosis was assessed using phagocytic index (PI). NO production from the culture supernatants was determined by the Griess reagent. The inducible nitric oxide synthase (iNOS) expression was determined by Western blot. The particles were also incubated with cells pretreated with various concentrations of L-N(6)-(1-iminoethyl) lysine hydrochloride (L-NIL) or L-arginine. Latex beads were used as a control. Our results showed that macrophage phagocytosis induced by HA was higher than that induced by the beads. However, NO production by HA-stimulated cells was lower than that by bead-stimulated cells. iNOS expression in both bead- and HA-stimulated cells was observed expressed at 7, 15, 30, and 60 min. l-Arginine enhanced but l-NIL inhibited both phagocytosis and NO production by HA-stimulated cells. The results of the present study suggest that nitric oxide may play a crucial role in HA-induced phagocytosis by RAW264.7 cells.

Matched MeSH terms: Phagocytosis/immunology*
Fulltext Immunostimulatory effects of the standardized extract of Tinospora crispa on innate immune responses in Wistar Kyoto rats

Ahmad W, Jantan I, Kumolosasi E, Bukhari SN

Drug Des Devel Ther, 2015;9:2961-73.
PMID: 26089645 DOI: 10.2147/DDDT.S85405

Tinospora crispa (TC) has been used in folkloric medicine for the treatment of various diseases and has been reported for several pharmacological activities. However, the effects of TC extract on the immune system are largely unknown. Therefore, the present study was aimed to investigate the immunomodulatory effects of a standardized 80% ethanol extract of the stem of TC on innate immune responses. Male Wistar Kyoto rats were treated daily at 100 mg/kg, 200 mg/kg, and 400 mg/kg doses of the extract for 21 days by oral gavage. The immunomodulatory potential of TC was evaluated by determining its effect on chemotaxis and phagocytic activity of neutrophils isolated from the blood of rats. To further elucidate the mechanism of action, its effects on the proliferation of T- and B-lymphocytes and T-lymphocytes subsets (CD4+ and CD8+) and on the secretion of Th1 and Th2 cytokines were also monitored. The main components of the extracts, syringin and magnoflorine, were identified and quantitatively analyzed in the extracts by using a validated reversed-phase high-performance liquid chromatography method. It was observed that the chemotactic activity of neutrophils obtained from extract-treated rats increased as compared to controls. A dose-dependent increase in the number of migrated cells and phagocytosis activity of neutrophils was observed. Dose-dependent increase was also observed in the T- and B-lymphocytes proliferation stimulated with concanavalin A (5 μg/mL) and lipopolysaccharide (10 μg/mL), and was statistically significant at 400 mg/kg (P>0.01). Apart from cell-mediated immune response, the concentrations of Th1 (TNF-α, IL-2, and IFN-γ) and Th2 (IL-4) cytokines were significantly increased in sera of rats treated with different doses as compared with the control group. From these findings, it can be concluded that TC possesses immunostimulatory activity and has therapeutic potential for the prevention of immune diseases.

Matched MeSH terms: Phagocytosis/drug effects
Zerumbone from Zingiber zerumbet inhibits innate and adaptive immune responses in Balb/C mice

Jantan I, Haque MA, Ilangkovan M, Arshad L

Int Immunopharmacol, 2019 Aug;73:552-559.
PMID: 31177081 DOI: 10.1016/j.intimp.2019.05.035

Zerumbone exhibited various biological properties including in vitro immunosuppressive effects. However, its modulatory activity on the immune responses in experimental animal model is largely unknown. This investigation was conducted to explore the effects of daily treatment of zerumbone (25, 50, and 100 mg/kg) isolated from Zingiber zerumbet rhizomes for 14 days on various cellular and humoral immune responses in Balb/C mice. For measurement of adaptive immunity, sheep red blood cells (sRBC) were used to immunize the mice on day 0 and orally fed with similar doses of zerumbone for 14 days. The effects of zerumbone on phagocytosis, nitric oxide (NO) release, myeloperoxidase (MPO) activity, proliferation of T and B cells, lymphocyte phenotyping, cytokines release in serum by activated T cells, delayed type hypersensitivity (DTH) and immunoglobulins production (IgG and IgM) were investigated. Zerumbone downregulated the engulfment of E. coli by peritoneal macrophages and the release of NO and MPO in a concentration-dependent manner. Zerumbone showed significant and concentration-dependent suppression of T and B lymphocytes proliferation and inhibition of the Th1 and Th2 cytokines release. At higher concentrations of zerumbone, the % expression of CD4+ and CD8+ in splenocytes was significantly inhibited. Zerumbone also concentration-dependently demonstrated strong suppression on sRBC-triggered swelling of mice paw in DTH. Substantial suppression of anti-sRBC immunoglobulins antibody titer was noted in immunized and zerumbone-treated mice in a concentration-dependent manner. The potent suppressive effects of zerumbone on the immune responses suggest that zerumbone can be a potential candidate for development of immunosuppressive agent.

Matched MeSH terms: Phagocytosis/drug effects
Fulltext Evaluation of phytoestrogens in inducing cell death mediated by decreasing Annexin A1 in Annexin A1-knockdown leukemia cells

Hasan M, Kumolosasi E, Jasamai M, Jamal JA, Azmi N, Rajab NF

Daru, 2020 Jun;28(1):97-108.
PMID: 31912375 DOI: 10.1007/s40199-019-00320-0

BACKGROUND: Phytoestrogens are plant compounds that are structurally similar to estrogen and that possess anti-cancer properties. Previous studies have reported that coumestrol, daidzein and genistein could induce cell death by reducing Annexin A1 protein in leukemic cell lines. Annexin A1 (ANXA1) is involved in cell progression, metastasis, and apoptosis in several types of cancer cells. The present study sought to investigate if the effects of phytoestrogens on apoptosis, cell cycle arrest and phagocytosis in ANXA1-knockdown leukemic cells are mediated through ANXA1 or occurred independently.
METHODS: Transfection of ANXA1 siRNA was conducted to downregulate ANXA1 expression in Jurkat, K562 and U937 cells. Apoptosis and cell cycle assays were conducted using flow cytometry. Western blot was performed to evaluate ANXA1, caspases and Bcl-2 proteins expression. Phagocytosis was determined using hematoxylin and eosin staining.
RESULTS: The expression of ANXA1 after the knockdown was significantly downregulated in all cell lines. Genistein significantly induced apoptosis associated with an upregulation of procaspase-3, -9, and - 1 in Jurkat cells. The Bcl-2 expression showed no significant difference in Jurkat, K562 and U937 cells. Treatment with phytoestrogens increased procaspase-1 expression in Jurkat and U937 cells while no changes were detected in K562 cells. Flow cytometry analysis demonstrated that after ANXA1 knockdown, coumestrol and genistein caused cell cycle arrest at G2/M phase in selected type of cells. The percentage of phagocytosis and phagocytosis index increased after the treatment with phytoestrogens in all cell lines.
CONCLUSION: Phytoestrogens induced cell death in ANXA1-knockdown leukemia cells, mediated by Annexin A1 proteins. Graphical abstract.

Matched MeSH terms: Phagocytosis/drug effects
Immunomodulatory effects of Tinospora crispa extract and its major compounds on the immune functions of RAW 264.7 macrophages

Ahmad W, Jantan I, Kumolosasi E, Haque MA, Bukhari SNA

Int Immunopharmacol, 2018 Jul;60:141-151.
PMID: 29730557 DOI: 10.1016/j.intimp.2018.04.046

The in vivo immunomodulatory activities of Tinospora crispa have been reported but its molecular mechanisms underlying its immunomodulatory properties remains obscure and the active constituents contributing to the activities have not been identified. The present study was aimed to investigate the immunomodulatory effects of T. crispa extract (TCE) and its chemical constituents on RAW 264.7 macrophages. Six known compounds including magnoflorine and syringin were isolated by various chromatographic techniques from TCE and their structures were determined spectroscopically. A validated HPLC method was used to quantify magnoflorine and syringin in the extract. The immunomodulatory effects of TCE and its isolated compounds on chemotaxis, phagocytosis, production of inflammatory mediators including reactive oxygen species (ROS), nitric oxide (NO), prostaglandin E2 (PGE2) and pro-inflammatory cytokines which include tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6 and monocyte chemoattractant protein-1 (MCP-1) on macrophages were assessed. TCE increased the chemotaxis and phagocytic activity of macrophages and significantly enhanced the production of ROS, NO and pro-inflammatory cytokines. All alkaloids isolated, specifically magnoflorine showed remarkable inducing effects on the chemotaxis, phagocytic activity, ROS and NO productions and the secretions of IL-1β, TNF-α, IL6, PGE2 and MCP-1. In contrast, syringin potently reduced the chemotaxis, phagocytic activity, ROS and NO productions and secretions of IL-1β, TNF-α, IL6, PGE2 and MCP-1. TCE showed strong immunostimulant effects on various components of the immune system and these activities were possibly contributed mainly by the alkaloids specifically magnoflorine. TCE has potential to be developed as an effective natural immunostimulant for improvement of immune-related disorders.

Matched MeSH terms: Phagocytosis
Fulltext Knockdown of Annexin A1 induces apoptosis, causing G2/M arrest and facilitating phagocytosis activity in human leukemia cell lines

Hasan M, Kumolosasi E, Jantan I, Jasamai M, Nazarudin N

Acta Pharm, 2022 Mar 01;72(1):109-122.
PMID: 36651527 DOI: 10.2478/acph-2022-0005

Annexin A1 (ANXA1) is an endogenous protein involved in the control of proliferation, cell cycle, phagocytosis, and apoptosis in several types of cancer. To investigate the effects of ANXA1 knockdown in leukemia cells, transfection with specific ANXA1 siRNA was performed. Cell cycle and apoptosis were analyzed using flow cytometry and a mechanism involving caspases and Bcl-2 was quantified using Western blotting. Phagocytosis activity was evaluated using hematoxylin & eosin staining. The ANXA1 expression was significantly downregulated after the knockdown and apoptosis was induced in tested cells. The expression of caspase-9 and -3 increased in U937 and Jurkat cells respectively. Bcl-2 expression was downregulated in K562 and Jurkat cells while upregulated in U937. The number of leukemic cells arrested at the G2/M phase and the phagocytosis index were significantly increased in transfected cells. This suggests that ANXA1 knockdown might be a potential approach in the therapeutic strategy for leukemia.

Matched MeSH terms: Phagocytosis
Fulltext Chronic granulomatous disease--a report in two Malay families

Mohd Noh L, Noah RM, Wu LL, Nasuruddin BA, Junaidah E, Ooi CP, et al.

Singapore Med J, 1994 Oct;35(5):505-8.
PMID: 7701372

Chronic granulomatous disease (CGD) is a very rare disease whose defect lies in an abnormal intracellular killing resulting in recurrent abscesses, lymphadenitis and granuloma formation. We describe 2 Malay male infants with CGD whom we believe to be the first report of this disorder in Malays. Both children presented with recurrent abscesses, pneumoniae and hepatosplenomegaly; lymphadenopathy was also present in one of the patients. The organisms isolated were catalase positive bacteria. Both neutrophil chemiluminescence (against fungal and bacterial antigens, phorbol myristate acetate) and intracellular killing assays were severely depressed. Recognition of CGD is important as great strides have been made in the treatment of this disease which include gamma interferon therapy besides the conventional prophylactic antibacterial therapy.

Matched MeSH terms: Phagocytosis
Fulltext The Hippo-YAP signaling pathway drives CD24-mediated immune evasion in esophageal squamous cell carcinoma via macrophage phagocytosis

Zhou X, Yan Z, Hou J, Zhang L, Chen Z, Gao C, et al.

Oncogene, 2024 Feb;43(7):495-510.
PMID: 38168654 DOI: 10.1038/s41388-023-02923-z

Esophageal squamous cell carcinoma (ESCC) is one of the most lethal malignancies in the world with poor prognosis. Despite the promising applications of immunotherapy, the objective response rate is still unsatisfactory. We have previously shown that Hippo/YAP signaling acts as a powerful tumor promoter in ESCC. However, whether Hippo/YAP signaling is involved in tumor immune escape in ESCC remains largely unknown. Here, we show that YAP directly activates transcription of the "don't eat me" signal CD24, and plays a crucial role in driving tumor cells to avoid phagocytosis by macrophages. Mechanistically, YAP regulates CD24 expression by interacting with TEAD and binding the CD24 promoter to initiate transcription, which facilitates tumor cell escape from macrophage-mediated immune attack. Our animal model data and clinical data show that YAP combined with CD24 in tumor microenvironment redefines the impact of TAMs on the prognosis of ESCC patients which will provide a valuable basis for precision medicine. Moreover, treatment with YAP inhibitor altered the distribution of macrophages and suppressed tumorigenesis and progression of ESCC in vivo. Together, our study provides a novel link between Hippo/YAP signaling and macrophage-mediated immune escape, which suggests that the Hippo-YAP-CD24 axis may act as a promising target to improve the prognosis of ESCC patients. A proposed model for the regulatory mechanism of Hippo-YAP-CD24-signaling axis in the tumor-associated macrophages mediated immune escape.

Matched MeSH terms: Phagocytosis
Fulltext Immunosuppressive effects of the standardized extract of Phyllanthus amarus on cellular immune responses in Wistar-Kyoto rats

Ilangkovan M, Jantan I, Mesaik MA, Bukhari SN

Drug Des Devel Ther, 2015;9:4917-30.
PMID: 26347462 DOI: 10.2147/DDDT.S88189

Phyllanthus amarus (family: Euphorbiaceae) is of immense interest due to its wide spectrum of biological activities. In the present study, the standardized 80% ethanol extract of P. amarus was investigated for its modulatory activity on various cellular immune parameters, including chemotaxis of neutrophils, engulfment of Escherichia coli by neutrophils, and Mac-1 expression, in leukocytes isolated from treated/nontreated Wistar-Kyoto rats. The detailed cell-mediated activity of P. amarus was also investigated, including analysis of the effects on T- and B-cell proliferation and CD4(+) and CD8(+) T-cell subsets in splenic mononuclear cells, and estimation of serum cytokine production by activated T-cells. The main components of the extract, phyllanthin, hypophyllanthin, corilagin, geraniin, ellagic acid, and gallic acid were identified and quantitatively analyzed in the extracts, using validated reversed-phase high-performance liquid chromatography (HPLC) methods. N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced neutrophils isolated from rats administered with the extract of P. amarus, at doses ranging from 100 to 400 mg/kg for 14 days, revealed a significant dose-dependent reduction in neutrophil migration (P<0.05). Similar patterns of inhibition were also observed in phagocytic activity and in fMLP-induced changes in expression of β2 integrin polymorphonuclear neutrophils. The results in P. amarus-treated rats also demonstrated a dose-dependent inhibition of both lipopolysaccharide-stimulated B-cell proliferation and concanavalin A-stimulated T-cell proliferation as compared with sensitized control. At a dose of 400 mg/kg (P<0.01), there was a significant decrease in the (%) expression of CD4(+) and CD8(+) in splenocytes and in serum cytokines of T helper (Th1) (IL-2 and IFN-γ) and Th2 (IL-4). In conclusion, P. amarus showed effective immunosuppressive activities in cellular immune response, by various immune regulatory mechanisms, and may be useful for improvement of immune-related disorders.

Matched MeSH terms: Phagocytosis/drug effects
Intracellular proteins involved in Porphyromonas gingivalis-induced opsonophagocytic activities of a murine macrophage cell line (RAW264.7 cells)

Sosroseno W, Bird PS, Seymour GJ

J Microbiol Immunol Infect, 2003 Dec;36(4):229-35.
PMID: 14723250

The aim of this study was to determine the role of intracellular proteins in phagocytosis of opsonized Porphyromonas gingivalis by RAW264.7 cells, a murine macrophage-like cell line. This periodontopathogen was grown anaerobically and opsonized with an IgG2a murine monoclonal anti-P. gingivalis lipopolysaccharide antibody. RAW264.7 cells were preincubated with protein tyrosine kinase inhibitors (staurosporine and genistein), protein kinase C inhibitors (phorbol myristic acetate and bisindolylmaleimide), a serine/threonine phosphatase inhibitor (okadaic acid), a phosphatidylinositol 3-kinase inhibitor (worthmannin), phospholipase A2 inhibitors (bromophenacyl bromide and nordihydroguaiaretic acid), phospholipase C inhibitors (p-chloromercuriphenyl sulfonate and neomycin sulfate), an actin-filament depolymerizer (cytochalasin D), and a microtubule disrupting agent (colchicine). Inhibitor-treated macrophages were then incubated with the opsonized P. gingivalis and the phagocytosed cells determined microscopically. The results showed the percentage of the phagocytosed organisms decreased when the cells were preincubated with protein tyrosine kinase, protein kinase C, protein phosphatase and phosphatidylinositol 3-kinase inhibitors. Of interest, preincubation with phorbol myristic acetate for 30 min increased the ability of RAW264.7 cells to phagocytose the opsonized organisms. Phospholipase A2 and phospholipase C inhibitors only slightly reduced the number of phagocytosed organisms. The results indicated that opsonophagocytosis of P. gingivalis by RAW264.7 cells might be determined by the activation of protein tyrosine kinase, protein kinase C, protein phosphatases, and phosphatidylinositol 3-kinase inhibitor. Both phospholipase A2 and phospholipase C would appear to be involved to a lesser extent. The opsonophagocytosis of this periodontopathogen would also appear to be dependent upon actin and microtubule polymerization.

Matched MeSH terms: Phagocytosis/drug effects

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