Expression and production of llama variable heavy-chain antibody fragments (VHHs) by Aspergillus awamori

We report the expression and production of llama variable heavy-chain antibody fragments (V(HH)s) by Aspergillus awamori. Fragments encoding V(HH)s were cloned in a suitable Aspergillus expression vector and transformants secreting V-HH fragments were analysed for integrated gene copy-numbers, mRNA levels and protein production. Functional V(HH)s were detected in the culture medium, indicating the feasibility of producing this type of protein in a fungal expression system. Secreted V(HH)s were subjected to (extracellular) degradation, which could be partially prevented by the addition of BSA to the culture medium.