Efficient production of human bivalent and trivalent anti-MUC1 Fab-scFv antibodies in Pichia pastoris.
BACKGROUND
Tumour associated antigens on the surface of tumour cells, such as MUC1, are being used as specific antibody targets for immunotherapy of human malignancies. In order to address the poor penetration of full sized monoclonal antibodies in tumours, intermediate sized antibodies are being developed. The cost-effective and efficient production of these molecules is however crucial for their further success as anti-cancer therapeutics. The methylotropic P. pastoris yeast grows in cheap mineral media and is known for its short process times and the efficient production of recombinant antibody fragments like scFvs, bivalent scFvs and Fabs.


RESULTS
Based on the anti-MUC1 PH1 Fab, we have developed bivalent PH1 bibodies and trivalent PH1 tribodies of intermediate molecular mass by adding PH1 scFvs to the C-terminus of the Fab chains using flexible peptide linkers. These recombinant antibody derivatives were efficiently expressed in both mammalian and P. pastoris cells. Stable production in NS0 cells produced 130.5 mg pure bibody and 27 mg pure tribody per litre. This high yield is achieved as a result of the high overall purification efficiency of 77%. Expression and purification of PH1 bibodies and tribodies from Pichia supernatant yielded predominantly correctly heterodimerised products, free of light chain homodimers. The yeast-produced bi- and tribodies retained the same specific activity as their mammalian-produced counterparts. Additionally, the yields of 36.8 mg pure bibody and 12 mg pure tribody per litre supernatant make the production of these molecules in Pichia more efficient than most other previously described trispecific or trivalent molecules produced in E. coli.


CONCLUSIONS
Bi- and tribody molecules are efficiently produced in P. pastoris. Furthermore, the yeast produced molecules retain the same specific affinity for their antigen. These results establish the value of P. pastoris as an efficient alternative expression system for the production of recombinant multivalent Fab-scFv antibody derivatives.
Schoonooghe
Steve
S
Department for Molecular Biomedical Research, VIB, Technologie Park 927, B-9052 Ghent, Belgium. sschoono@vub.ac.be
Kaigorodov
Vladimir
V
Zawisza
Monika
M
Dumolyn
Caroline
C
Haustraete
Jurgen
J
Grooten
Johan
J
Mertens
Nico
N
D000818:Animals; D002460:Cell Line; D015870:Gene Expression; D005822:Genetic Vectors; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D051379:Mice; D018396:Mucin-1 / Q000276:immunology*; D010843:Pichia / Q000378:metabolism*; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification
D007140:Immunoglobulin Fab Fragments; D007135:Immunoglobulin Variable Region; C060192:MUC1 protein, human; D018396:Mucin-1; D011994:Recombinant Proteins