Fig 4. Effector cell retargeting and activation by bispecific scDb fusion proteins determined by IL–2 release.
CEA positive target cells (LS174T) were incubated with scDb-SpGC3 variants together with or without 100 μg/ml human IgG 1 h prior to addition of PBMCs. Cell free supernatant was analyzed after 24 h for released IL-2 by ELISA.