High-level Secretion Expression of Human ScFv Against Botulinum Neurotoxin A in Pichia pastoris* / 微生物学通报

The specific ScFv gene against botulinum neurotoxin A (BoNTa)was cloned into pPIC9k. Positive integrators were screened by increasing the dose of G418 in culture and expressed in Pichia pastoris GS115. As a result, engineered recombinant clone were obtained. 26 kD product of interest was seen easily in SDS-PAGE. Expression of human ScFv got the highest level 15% of total secreted proteins during 72～84 h after 1% methanol inducing. Purification of ScFv was finished by two steps: gel filter and ion exchange. Competing ELISA showed that recombinant ScFv could compete with antiserum to specific bind BoNTa.