Alemtuzumab mediates robust cytolysis of purified T cells but not NK cells.

<p>Blocking anti CIP antibodies partially reverse the resistance of monocytes to lysis by alemtuzumab: PBMCs from each of the 4 donors were sorted using a FACS Aria cell sorter into CD3+ T, CD56+ NK and CD14+ CD11c+ monocytes to >95% purity. Each of these purified populations was subjected to a CDC assay in the presence or absence of 15 µg/ml of anti-CD55 and anti-CD59 antibodies. The percent cytolysis was assessed as described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0039416#pone-0039416-g005" target="_blank">Fig 5</a>.The hatched bars represent lysis with alemtuzumab without the blocking anti-CD55 and anti-CD59 antibodies and the shaded bars in the presence of blocking antibodies. The control IgG1 values were subtracted before plotting the data. (Background IgG1 range for T cells = 5–10%; NK cells = 5−15%; and monocytes = 15−31%). *p≤0.01 (IgG vs Alem alone) **p≤0.001 (Alem alone vs Alem + anti-CIP abs).