All procedures involving animal models have been reviewed by the local institutional animal care committee and the JoVE veterinary review board.

1. Serial Blood Collection and Plasma Monitoring for Exogenous Human Cytokine in Mice

1. Blood collection via tail snip
   1. Disinfect the biosafety hood and assemble the mouse restrainer, scissors, and other tools/supplies for the procedure.
   2. Place the mouse in a restrainer and secure the tube to minimize mouse movement.
   3. Disinfect the tail and surgical scissors with isopropyl alcohol. Apply topical anesthetic cream on the tail.
   4. Using very sharp surgical scissors snip off about 0.5 – 1 mm of the tip of the mouse's tail. Collect approximately 80 µL of peripheral blood using heparinized capillary tubes.
      NOTE: If blood will be collected with this method more than six times, tail removal should be conservative with respect to the amount of tail removed. As snips progress up the tail the diameter increases, it hemorrhages faster, and healing takes longer.

2. Plasma separation

1. Transfer the blood using a bulb syringe (to expel it from the capillary tubes) into a labeled K₂EDTA microtainer tube; invert 20 times to prevent coagulation.
   NOTE: Typically, blood clotting from the tail nip is fast. However, if hemorrhage persists longer than ~ 2 min use a styptic pencil/powder to aid coagulation.
2. Centrifuge blood collection tubes according to the manufacturer's instruction and aliquot the plasma for storage (-20 °C) until ready for further analysis.