C5-PE38

**C5-PE38** is an ambiguous preclinical recombinant nanobody-PE38 immunotoxin construct name that has been independently used for at least two distinct molecules. One construct combines a canine B-cell-lymphoma-selective C5 single-domain antibody with the truncated *Pseudomonas aeruginosa* exotoxin A payload PE38 and showed cytotoxicity and tumor-growth inhibition in canine B-cell lymphoma models. A separate construct uses a C5 nanobody directed against cell-surface glucose-regulated protein 78 and was evaluated in colorectal cancer and melanoma models, where it induced endoplasmic-reticulum stress, apoptosis, immunogenic cell death, and STING-associated antitumor immune activation. These constructs should not be treated as one molecular asset merely because they share the same published construct name. ([frontiersin.org](https://www.frontiersin.org/journals/veterinary-science/articles/10.3389/fvets.2025.1491934/full))

Other names

C5-PE38 immunotoxinC-5-PE38 immunotoxinC 5-PE38 immunotoxin