Preparation and use of gene banks of synthetic human antibodies ("synthetic human-antibody libraries")

A process for preparing a synthetic human antibody-DNA library, which comprises:

• 1) synthesizing almost random sequences for the antibody hypervariable regions, wherein
• (a) relatively conserved amino acids in the hypervariable regions have been taken into account in the choice of appropriate nucleotides during the oligonucleotide synthesis and
• (b) the ratio of the nucleotides used in chosen such that a nonsense codon is to be expected at most in every 89th position;
• 2) inserting said almost random sequences for the hypervariable regions into a human antibody framework;
• and
• 3) incorporating said almost random sequences combined with said human antibody framework into an expression vector.

A process for obtaining clones secreting specific human antibodies comprising the steps of:

• a) screening synthetic human antibody-DNA libraries using specific antigens, and
• b) isolating said clones which secrete the desired specific human antibodies,
• wherein said specific human antibody-DNA library is obtained by:
• 1) synthesizing almost random sequences for the antibody hypervariable regions, wherein
• (a) relatively conserved amino acids in the hypervariable regions have been taken into account in the choice of appropriate nucleotides during the oligonucleotide synthesis and
• (b) the ratio of the nucleotides used in chosen such that a nonsense codon is to be expected at most in every 89th position;
• 2) inserting said almost random sequences for the hypervariable regions into a human antibody framework;
• and
• 3) incorporating said almost random sequences combined with said human antibody framework into an expression vector.