Engineering human monoclonal antibody fragments: a recombinant enzyme-linked Fab.
A new plasmid vector, pCRP, allowing the expression of human recombinant monoclonal antibody Fab fragments fused with a bacterial acid phosphatase has been constructed. pCRP can accept heavy- and light-chain cDNAs cloned from combinatorial antibody libraries displayed on filamentous phages with the pCombIII system and is able to direct expression to soluble Fabs in which the carboxy-terminus of the heavy chain is fused to the amino-terminus of the mature PhoN nonspecific acid phosphatase of Providencia stuartii. Using the pCRP vector, we expressed two different human recombinant Fabs cloned from combinatorial libraries (one anti-tetenus toxoid and the other anti-HIV-1 gp120) fused with the acid phosphatase. In both cases chimeric antibodies were obtained which retained the antigen-binding ability and the enzymatic activity. Similar Fab-enzyme fusions can be successfully used, even unpurified, in enzyme immunoassays.
Burioni
R
R
Istituto di Microbiologia, Università Cattolica del S. Cuore, Roma, Italy.
Plaisant
P
P
Riccio
M L
ML
Rossolini
G M
GM
Santangelo
R
R
Vannini
A
A
Satta
G
G
D000135:Acid Phosphatase / Q000235:genetics / Q000378:metabolism; D000911:Antibodies, Monoclonal / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D015723:Gene Library; D005798:Genes, Bacterial / Q000235:genetics; D005822:Genetic Vectors / Q000235:genetics; D015699:HIV Envelope Protein gp120 / Q000276:immunology; D015497:HIV-1; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000096:biosynthesis* / Q000235:genetics; D008969:Molecular Sequence Data; D011532:Providencia / Q000201:enzymology; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis*; D013745:Tetanus Toxoid / Q000276:immunology
D000911:Antibodies, Monoclonal; D015699:HIV Envelope Protein gp120; D007140:Immunoglobulin Fab Fragments; D011993:Recombinant Fusion Proteins; D013745:Tetanus Toxoid; D000135:Acid Phosphatase