Abstract: The invention relates to the preparation and use of gene banks of human antibodies (Ab). Starting from a mixture of human B-lymphocytes, their mRNA is translated into the cDNA using oligo-dT primers. Subsequently, an amplification of the Ab-specific cDNA by means of polymerase chain reaction (PCR) takes place using suitable oligonucleotide primer sequences. Expression of this amplified Ab-specific cDNA in a bacterial expression vector, e.g. the vector pFMT described below, in E. coli thus makes available a human-antibody library with a comprehensive repertoire for screening selected antigens in vitro.

Abstract: The invention relates to the preparation and use of gene banks of synthetic human antibodies (huAb) or parts of antibodies which contain the antigen-binding domain. Starting from a huAb framework in a suitable vector, the hypervariable regions of the antibody cDNA are formed by almost "randomly" combined oligonucleotides. Relatively conserved amino acids in the hypervariable regions have here been taken account of in the choice of appropriate nucleotides during the oligonucleotide synthesis and the ratio of the nucleotides used is likewise chosen such that a nonsense codon is to be expected at most in every 89th position. Expression of this synthetic huAb cDNA in microbial expression systems, e.g. in E. coli in the vector pFMT which is described below, thus makes a synthetic huAb library with a comprehensive repertoire for screening using selected antigens available in vitro.