Role of monocytes in mediating HIV-specific antibody-dependent cellular cytotoxicity

M. Kramski, A. Schorcht, A.P.R. Johnston, G.F. Lichtfuss, S. Jegaskanda, R. De Rose, I. Stratov, A.D. Kelleher, Martyn French, R.J. Center, A. Jaworowski, S.J. Kent

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    Abstract

    Antibodies (Abs) that mediate antibody-dependent cellular cytotoxicity (ADCC) activity againstHIV-1 are of major interest. A widely used method to measure ADCC Abs is the rapid andfluorometric antibody-dependent cellular cytotoxicity (RFADCC) assay. Antibody-dependentkilling of a labelled target cell line by PBMC is assessed by loss of intracellular CFSE but retention ofmembrane dye PKH26 (CFSE-PKH26+). Cells of this phenotype are assumed to be derived fromCFSE+PKH26+ target cells killed by NK cells.We assessed the effector cells that mediate ADCC in this assay. Backgating analysis andphenotyping of CFSE-PKH26+ revealed that the RFADCC assay's readout mainly representsCD3-CD14+ monocytes taking up the PKH26 dye. This was confirmed for 53 HIV+plasmapurifiedIgG samples when co-cultured with PBMC from three separate healthy donors.Emergence of the CFSE-PKH26+monocyte population was observed upon co-culture of targetswith purified monocytes but not with purified NK cells. Image flow cytometry and microscopyshowed a monocyte-specific interaction with target cells without typical morphologicalchanges associated with phagocytosis, suggesting a monocyte-mediated ADCC process.We conclude that the RFADCC assay primarily reflects Ab-mediated monocyte function.Further studies on the immunological importance of HIV-specific monocyte-mediated ADCCare warranted. © 2012 Elsevier B.V. All rights reserved.
    Original languageEnglish
    Pages (from-to)51-61
    JournalJournal of Immunological Methods
    Volume384
    Issue number1/2
    Early online date24 Jul 2012
    DOIs
    Publication statusPublished - 31 Oct 2012

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    Kramski, M., Schorcht, A., Johnston, A. P. R., Lichtfuss, G. F., Jegaskanda, S., De Rose, R., ... Kent, S. J. (2012). Role of monocytes in mediating HIV-specific antibody-dependent cellular cytotoxicity. Journal of Immunological Methods, 384(1/2), 51-61. https://doi.org/10.1016/j.jim.2012.07.006