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  1. Fulltext Impaired NK Cell Activation and Chemotaxis toward Dendritic Cells Exposed to Complement-Opsonized HIV-1
    Ellegård R, Crisci E, Andersson J, Shankar EM, Nyström S, Hinkula J, et al.
    J Immunol, 2015 Aug 15;195(4):1698-704.
    PMID: 26157174 DOI: 10.4049/jimmunol.1500618
    Mucosa resident dendritic cells (DCs) may represent one of the first immune cells that HIV-1 encounters during sexual transmission. The virions in body fluids can be opsonized with complement factors because of HIV-mediated triggering of the complement cascade, and this appears to influence numerous aspects of the immune defense targeting the virus. One key attribute of host defense is the ability to attract immune cells to the site of infection. In this study, we investigated whether the opsonization of HIV with complement (C-HIV) or a mixture of complement and Abs (CI-HIV) affected the cytokine and chemokine responses generated by DCs, as well as their ability to attract other immune cells. We found that the expression levels of CXCL8, CXCL10, CCL3, and CCL17 were lowered after exposure to either C-HIV or CI-HIV relative to free HIV (F-HIV). DCs exposed to F-HIV induced higher cell migration, consisting mainly of NK cells, compared with opsonized virus, and the chemotaxis of NK cells was dependent on CCL3 and CXCL10. NK cell exposure to supernatants derived from HIV-exposed DCs showed that F-HIV induced phenotypic activation (e.g., increased levels of TIM3, CD69, and CD25) and effector function (e.g., production of IFNγ and killing of target cells) in NK cells, whereas C-HIV and CI-HIV did not. The impairment of NK cell recruitment by DCs exposed to complement-opsonized HIV and the lack of NK activation may contribute to the failure of innate immune responses to control HIV at the site of initial mucosa infection.
    Matched MeSH terms: Chemotaxis/immunology*
  2. Flavonoids of Artocarpus heterophyllus Lam. heartwood inhibit the innate immune responses of human phagocytes
    Septama AW, Jantan I, Panichayupakaranant P
    J Pharm Pharmacol, 2018 Sep;70(9):1242-1252.
    PMID: 29943393 DOI: 10.1111/jphp.12952
    OBJECTIVES: To investigate the effects of flavonoids isolated from Artocarpus heterophyllus. heartwood on chemotaxis, phagocytosis, reactive oxygen species (ROS) production and myeloperoxidase (MPO) activity of human phagocytes.

    METHODS: Chemotaxis was evaluated using a modified Boyden chamber and phagocytosis was determined by flowcytometer. Respiratory burst was investigated by luminol-based chemiluminescence assay while MPO activity was determined by colorimetric assay.

    KEY FINDINGS: Artocarpanone and artocarpin strongly inhibited all steps of phagocytosis. Artocarpanone and artocarpin showed strong chemotactic activity with IC50 values of 6.96 and 6.10 μm, respectively, which were lower than that of ibuprofen (7.37 μm). Artocarpanone was the most potent compound in inhibiting ROS production of polymorphonuclear leucocytes and monocytes with IC50 values comparable to those of aspirin. Artocarpin at 100 μg/ml inhibited phagocytosis of opsonized bacteria (28.3%). It also strongly inhibited MPO release with an IC50 value (23.3 μm) lower than that of indomethacin (69 μm). Structure-activity analysis indicated that the number of hydroxyl group, the presence of prenyl group and variation of C-2 and C-3 bonds might contribute towards their phagocytosis.

    CONCLUSIONS: Artocarpanone and artocarpin were able to suppress strongly the phagocytosis of human phagocytes at different steps and have potential to be developed into potent anti-inflammatory agents.

    Matched MeSH terms: Chemotaxis/immunology
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