Pharmacologic targeting of PDIs reduces ALLC secretion from ALMC-2 cells. (A) Graph showing normalized ALLC secretion from ALMC-2 cells treated for 18 hours with vehicle, 147 (10 µM), RB-11-ca (30 µM), or KSC-34 (30 µM). ALLC was quantified by ELISA. Error bars show standard error of the mean (SEM) for >9 replicates across >2 independent experiments. (B) Representative nonreducing (−DTT) and reducing (+DTT) immunoblots of conditioned media prepared from ALMC-2 cells treated for 18 hours with vehicle, 147 (10 µM), or RB-11-ca (30 µM). Fully assembled IgGs, oxidized LC dimers, oxidized LC monomers, and reduced LC monomers are indicated. (C) Graph showing normalized quantification of nonreducing immunoblots as shown in panel B for oxidized LC monomers, oxidized LC dimers, and fully assembled IgGs. Error bars show SEM for >2 independent experiments. (D) Graph showing normalized quantification of ALLC in lysates prepared from ALMC-2 cells treated for 18 hours with vehicle, 147 (10 µM), or RB-11-ca (30 µM). ALLC was measured by immunoblotting. Error bars show SEM for 4 independent experiments. (E) Representative immunoblot of ALLC immunopurified from ALMC-2 cells treated for 5 hours with vehicle, 147 (10 µM), or RB-11-ca (30 µM). (F) Normalized quantification of PDIA1 and PDIA4 from immunoblots as shown in panel E. The recovery of each PDI was normalized to the recovery of ALLC under each condition, allowing accurate evaluation of the interaction between these 2 proteins. Error bars show SEM for >2 independent experiments. *P < .05, **P < .01 (paired Student t test); ***P < .005 (unpaired Student t test).