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

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• 作者：M. Kramski ; A. Schorcht ; A.P.R. Johnston ; G.F. Lichtfuss ; S. Jegask ; a ; R. De Rose ; I. Stratov ; A.D. Kelleher ; M.A. French ; R.J. Center ; A. Jaworowski ; S.J. Kent
• 关键词：HIV-1 ; human immunodeficiency virus type 1 ; ADCC ; antibody-dependent cellular cytotoxicity ; RFACCC assay ; rapid fluorometric antibody-dependent cellular cytotoxicity assay ; CFSE ; Carboxyfluorescein succinimidyl ester
• 刊名：Journal of Immunological Methods
• 出版年：2012
• 出版时间：31 October, 2012
• 年：2012
• 卷：384
• 期：1-2
• 页码：51-61
• 全文大小：1888 K

文摘

Antibodies (Abs) that mediate antibody-dependent cellular cytotoxicity (ADCC) activity against HIV-1 are of major interest. A widely used method to measure ADCC Abs is the rapid and fluorometric antibody-dependent cellular cytotoxicity (RFADCC) assay. Antibody-dependent killing of a labelled target cell line by PBMC is assessed by loss of intracellular CFSE but retention of membrane dye PKH26 (CFSE-PKH26 +). Cells of this phenotype are assumed to be derived from CFSE + PKH26 + target cells killed by NK cells.

We assessed the effector cells that mediate ADCC in this assay. Backgating analysis and phenotyping of CFSE-PKH26 + revealed that the RFADCC assay's readout mainly represents CD3-CD14 + monocytes taking up the PKH26 dye. This was confirmed for 53 HIV + plasma-purified IgG samples when co-cultured with PBMC from three separate healthy donors. Emergence of the CFSE-PKH26 + monocyte population was observed upon co-culture of targets with purified monocytes but not with purified NK cells. Image flow cytometry and microscopy showed a monocyte-specific interaction with target cells without typical morphological changes 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 ADCC are warranted.