Production and tumour-binding characterization of a chimeric anti-CEA Fab expressed in Escherichia coli.
A recombinant chimeric Fab (rcFab), with Fv derived from the monoclonal A5B7 antibody to carcinoembryonic antigen (CEA), and with human CHI and C kappa was cloned into pUC 19 and expressed in Escherichia coli. rcFab (10 to 12 mg per litre) was produced in bacterial culture fluid, and functional purified rcFab was isolated by affinity chromatography (using antibody to human C kappa) and size-exclusion gel filtration. The rcFab did not show reduced affinity for CEA, and reacted with human colorectal tumours showing a typical anti-CEA pattern by immunocytochemistry; it was also stable after iodination. Biodistribution studies in nude mice bearing human tumour xenografts showed no toxicity and good tumour localization. Therapeutic ratios at early time points were better than those obtained with whole murine antibody. The results demonstrate that bacterially produced anti-CEA Fab is of use for tumour targeting.
Chester
K A
KA
Department of Clinical Oncology, Royal Free Hospital School of Medicine, London, UK.
Robson
L
L
Keep
P A
PA
Pedley
R B
RB
Boden
J A
JA
Boxer
G M
GM
Hawkins
R E
RE
Begent
R H
RH
D000230:Adenocarcinoma / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002272:Carcinoembryonic Antigen / Q000276:immunology*; D003001:Cloning, Molecular; D015179:Colorectal Neoplasms / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D015870:Gene Expression / Q000235:genetics; D006801:Humans; D007127:Immunoglobulin Constant Regions / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D007128:Immunoglobulin Fragments / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D007135:Immunoglobulin Variable Region / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism*; D014018:Tissue Distribution; D014183:Transplantation, Heterologous
D002272:Carcinoembryonic Antigen; D007127:Immunoglobulin Constant Regions; D007128:Immunoglobulin Fragments; D007135:Immunoglobulin Variable Region; D011993:Recombinant Fusion Proteins