Re: NK cytotoxicity assay with human whole blood

From: William Telford (TelfordW@mail.nih.gov)
Date: Fri Jun 28 2002 - 23:29:50 EST





Hello Lee...

We have used a NK/cytolytic T cell assay from Oncoimmunin, Inc. (the CyToxiLux kit) to measure human NK activity.  The assay uses a fluorogenic caspase 6 substrate (similar to their PhiPhiLux caspase 3 substrate) that is loaded immediately after target:effector coincubation - target cells are tagged prior to coincubation with a proprietary red tracking dye to distinguish them from effectors.  Both probes excite at 488 nm, so you can analyze on almost any benchtop flow cytometer, gating on the tagged targets.  Caspase 6 is probably one of the earliest cytolysis-associated events you can detect using current methods - it gives much higher sensitivity than 51Cr in our hands.  We've used it with both peripheral blood derived NKs and NK92 cells, using K562 and Jurkat targets.

Oncoimmunin's web site is at http://www.phiphilux.com.  We have some NK data using this assay posted on our website at http://home.ncifcrf.gov/ccr/flowcore/cytox.htm.

Enjoy,

Bill

 At 11:49 AM 6/25/2002 -0400, Lam, Lee wrote:

Dear all,
Our lab would like to use flow cytometry for the measuring natural killer
cell cytotoxicity. Does anyone have a working protocol that can share with
us? Also, could we use 24 hrs. old human whole blood instead of PBMC for the
assay? It will be really appreciated if you can provide us with valuable
pointers.  Thanks in advance.
        Lee Lam
        CDC
        Atlanta, Georgia
        Phone: 404-639-2725
        Fax:    404-639-4838
        E-mail:  LXL7@CDC.GOV <mailto:LXL7@CDC.GOV>



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