Recently, a new format for the cytokine release assay (CRA) used to predict the in vivo safety of therapeutic antibodies was developed. In this assay, normal donor PBMCs are pre-incubated at high density for two days to make the cells more “lymph node like” (LNL) and then are incubated with soluble antibody. The assay was developed in response to the failure of previous in vitro stimulation formats to predict the strong cytokine storm shown in humans by TGN1412, a CD28 superagonist human IgG4 antibody. Similar to TGN1412, previous formats failed to predict the strong cytokine response elicited in human patients by visilizumab, a human IgG2a anti-CD3 specific antibody. Here we compare and contrast the PBMC response in the LNL format to TGN1412 and visilizumab. Activation of PBMC subset populations, cytokine profile and cellular source of cytokines were analyzed. For the majority of donors tested, the LNL format of CRA detected PBMC cytokine responses to both TGN1412 and visilizumab, which were consistent with those cytokine responses previoulsly observed in vivo. Our study of two human IgG antibodies targeting different T cell activating receptors suggests that the LNL format of CRA may be a valuable predictor of in vivo cytokine release by T lymphocyte specific biologics.
- Copyright © 2013 by The American Association of Immunologists, Inc.