20ug/mL), so I add 0.5mL of the CASTA stock to 9.5mL of RPMI-10% (400ug/mL x 0.5mL = 200ug in 10mL, or 20ug/mL).
5.18. The CMV antigen is a liquid that comes in a 5mL vial. I need 10mL of a 1:5 dilution, so I add 2mL of the CMV stock to 8mL of RPMI -10%.
5.19. The remaining CASTA and CMV antigen from the stock vials can be transferred aseptically to small cryovials and stored at –70°C.
5.20. Preparation of plates:
5.20.1. Tissue culture plates should be prepared in advance and stored in sealable plastic bags at –70°C. The preparation of a large number of plates in advance increases the uniformity of antigen addition and facilitates the rapid processing of a large number of blood specimens.
5.20.2. Obtain plate diagram (i.e. “worksheet”, “template”) for the LPA from the PIIS. The PIIS should also specify whether assays will be run in triplicate or quadruplicate. It is essential that all sites performing a given study place antigens in the same positions on the plate.
5.20.3. Dispense 100μL/well of each 2X concentration antigen/mitogen in strict accordance with the plate diagram provided. For control wells, dispense 100μL of RPMI -10% (see note in Section 5, Detailed Protocol, if RPMI -20% is preferred).
5.21. Preparation of [3H]TdR:
5.21.1. The final concentration of [3H]TdR should be 1μCi/well. Calculate the volume of diluted [3H]TdR needed to dispense 25μL/well, equaling 1μCi/well (number of assay wells x 25μL/well = minimum volume to prepare). For example, the [3H]TdR stock is at 1mCi/mL. A working solution of 40μCi/mL in RPMI-0 (or D-PBS) should be prepared. Dilute the [3H]TdR stock 1:25 with RPMI-0 (0.5mL of stock + 12mL media). This is enough to pulse 500 wells. Add 25μL/well to give a final concentration of 1.0μCi/well. The diluted [3H]TdR can be stored at 4°C for a month.
5.22. Preparation of PBMCs
5.22.1. Check the consensus protocol for preparation of PBMCs found in the Virology Manual for HIV Laboratories, “Preparation of PHA-stimulated uninfected donor peripheral blood mononuclear cells” on the web at: http://www.niaid.nih.gov/daids/vir_manual/.
5.22.2. If the blood collection tube has been spun to obtain the plasma fraction, D-PBS or RPMI-0 equal to the original volume of the plasma must be added to the tube. Now add sterile D-PBS or RPMI -0 equal to the volume of blood so that the volume is 2X the original volume.
5.22.3. Overlay diluted blood on Ficoll-hypaque.
5.22.4. Centrifuge at 300-400 x g for 30 minutes in a room temperature centrifuge (20° to 25°C). Make sure the centrifuge brake is turned off.
5.22.5. Harvest the PBMC from the interface and immediately wash two or three times in D-PBS or RPMI -0, centrifuging at 200 x g for 12 minutes at room temperature. Minimize delay time between washes. After washing,