Browsing by Author "Koup, Richard A"

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    Application of area scaling analysis to identify natural killer cell and monocyte involvement in the GranToxiLux antibody dependent cell-mediated cytotoxicity assay.
    (Cytometry. Part A : the journal of the International Society for Analytical Cytology, 2018-04) Pollara, Justin; Orlandi, Chiara; Beck, Charles; Edwards, R Whitney; Hu, Yi; Liu, Shuying; Wang, Shixia; Koup, Richard A; Denny, Thomas N; Lu, Shan; Tomaras, Georgia D; DeVico, Anthony; Lewis, George K; Ferrari, Guido
    Several different assay methodologies have been described for the evaluation of HIV or SIV-specific antibody-dependent cell-mediated cytotoxicity (ADCC). Commonly used assays measure ADCC by evaluating effector cell functions, or by detecting elimination of target cells. Signaling through Fc receptors, cellular activation, cytotoxic granule exocytosis, or accumulation of cytolytic and immune signaling factors have been used to evaluate ADCC at the level of the effector cells. Alternatively, assays that measure killing or loss of target cells provide a direct assessment of the specific killing activity of antibodies capable of ADCC. Thus, each of these two distinct types of assays provides information on only one of the critical components of an ADCC event; either the effector cells involved, or the resulting effect on the target cell. We have developed a simple modification of our previously described high-throughput ADCC GranToxiLux (GTL) assay that uses area scaling analysis (ASA) to facilitate simultaneous quantification of ADCC activity at the target cell level, and assessment of the contribution of natural killer cells and monocytes to the total observed ADCC activity when whole human peripheral blood mononuclear cells are used as a source of effector cells. The modified analysis method requires no additional reagents and can, therefore, be easily included in prospective studies. Moreover, ASA can also often be applied to pre-existing ADCC-GTL datasets. Thus, incorporation of ASA to the ADCC-GTL assay provides an ancillary assessment of the ability of natural and vaccine-induced antibodies to recruit natural killer cells as well as monocytes against HIV or SIV; or to any other field of research for which this assay is applied. © 2018 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of ISAC.
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    Immunological and virological mechanisms of vaccine-mediated protection against SIV and HIV.
    (Nature, 2014-01-23) Roederer, Mario; Keele, Brandon F; Schmidt, Stephen D; Mason, Rosemarie D; Welles, Hugh C; Fischer, Will; Labranche, Celia; Foulds, Kathryn E; Louder, Mark K; Yang, Zhi-Yong; Todd, John-Paul M; Buzby, Adam P; Mach, Linh V; Shen, Ling; Seaton, Kelly E; Ward, Brandy M; Bailer, Robert T; Gottardo, Raphael; Gu, Wenjuan; Ferrari, Guido; Alam, S Munir; Denny, Thomas N; Montefiori, David C; Tomaras, Georgia D; Korber, Bette T; Nason, Martha C; Seder, Robert A; Koup, Richard A; Letvin, Norman L; Rao, Srinivas S; Nabel, Gary J; Mascola, John R
    A major challenge for the development of a highly effective AIDS vaccine is the identification of mechanisms of protective immunity. To address this question, we used a nonhuman primate challenge model with simian immunodeficiency virus (SIV). We show that antibodies to the SIV envelope are necessary and sufficient to prevent infection. Moreover, sequencing of viruses from breakthrough infections revealed selective pressure against neutralization-sensitive viruses; we identified a two-amino-acid signature that alters antigenicity and confers neutralization resistance. A similar signature confers resistance of human immunodeficiency virus (HIV)-1 to neutralization by monoclonal antibodies against variable regions 1 and 2 (V1V2), suggesting that SIV and HIV share a fundamental mechanism of immune escape from vaccine-elicited or naturally elicited antibodies. These analyses provide insight into the limited efficacy seen in HIV vaccine trials.