HSPA5 and mantle cell lymphoma: Because upregulation of the chaperone BiP is central to restoring homeostasis after UPR, we initially tested whether an arrest of protein synthesis by the FDA-approved, CD22-targeted immunotoxin Moxetumomab pasudotox (Lumoxiti®, Moxe) influenced BiP expression in B cell malignancy cell lines JeKo-1 (mantle cell lymphoma, MCL) and Ramos (Burkitt’s lymphoma, BL) (Fig. 1A, B).