Development of an in vitro potency bioassay for therapeutic IL-13 antagonists: the A-549 cell bioassay.
Interleukin 13 is a key cytokine that mediates airway hyper-responsiveness and mucus over-production, and several anti-IL-13 therapeutic antibodies are currently in clinical development for the treatment of asthma. Conventional cell-based bioassays for evaluating neutralization potencies of IL-13 antagonists are semi-quantitative or with a low sensitivity. Here, we report the development of a highly sensitive bioassay to assess the potency of IL-13 antagonists using human lung epithelial A-549 cells that produce thymus and activation-regulated chemokine (TARC) in response to IL-13 stimulation. The A-549 cells were responsive to both wild type and a variant form of recombinant human IL-13 in a concentration-dependent manner, with a 16 to 24 h exposure time found to be within the linear portion of the bioassay response range. The Effective Concentration at 50% of the maximal response (ED50) of IL-13 determined for the assay was 1-5 ng/mL. With this level of IL-13, an anti-IL-13 antibody B-B13 yielded an approximate median Inhibitory Concentration (IC50) value of 0.2 nM. Bioassay optimization was performed to achieve best assay condition and sensitivity. Additionally, IL-13 antagonist potency against natural human IL-13 was also investigated in the A-549 cell bioassay.
Miller
Renee
R
Department of Biologics, Abbott Bioresearch Center, Worcester, MA 01605, United States.
Sadhukhan
Ramkrishna
R
Wu
Chengbin
C
D000818:Animals; D001681:Biological Assay / Q000379:methods*; D045744:Cell Line, Tumor; D054414:Chemokine CCL17 / Q000276:immunology / Q000378:metabolism*; D004847:Epithelial Cells / Q000276:immunology / Q000378:metabolism; D006801:Humans; D018793:Interleukin-13 / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000378:metabolism; D053661:Interleukin-13 Receptor alpha1 Subunit / Q000276:immunology / Q000378:metabolism; D053663:Interleukin-13 Receptor alpha2 Subunit / Q000276:immunology / Q000378:metabolism; D007376:Interleukin-2 / Q000276:immunology; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism; D012680:Sensitivity and Specificity; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
C106230:CCL17 protein, human; D054414:Chemokine CCL17; C508181:IL13RA1 protein, human; C508594:IL2 protein, human; D018793:Interleukin-13; D053661:Interleukin-13 Receptor alpha1 Subunit; D053663:Interleukin-13 Receptor alpha2 Subunit; D007376:Interleukin-2; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha