Browsing by keyword "Killer-Oberpfalzer, Monika"
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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 assaySeveral 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.
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KSHV infection drives poorly cytotoxic CD56-negative natural killer cell differentiation in vivo upon KSHV/EBV dual infectionHerpesvirus infections shape the human natural killer (NK) cell compartment. While Epstein-Barr virus (EBV) expands immature NKG2A(+) NK cells, human cytomegalovirus (CMV) drives accumulation of adaptive NKG2C(+) NK cells. Kaposi sarcoma-associated herpesvirus (KSHV) is a close relative of EBV, and both are associated with lymphomas, including primary effusion lymphoma (PEL), which nearly always harbors both viruses. In this study, KSHV dual infection of mice with reconstituted human immune system components leads to the accumulation of CD56(-)CD16(+)CD38(+)CXCR6(+) NK cells. CD56(-)CD16(+) NK cells were also more frequently found in KSHV-seropositive Kenyan children. This NK cell subset is poorly cytotoxic against otherwise-NK-cell-susceptible and antibody-opsonized targets. Accordingly, NK cell depletion does not significantly alter KSHV infection in humanized mice. These data suggest that KSHV might escape NK-cell-mediated immune control by driving CD56(-)CD16(+) NK cell differentiation.

