BORNHEIM, Germany ¿ Pieris Proteolab AG, of Freising, disclosed a library of what it calls anticalins that contains more than 10 billion structures.

Anticalins have antibody-like functions, but are much smaller than antibodies and can be produced more easily in bacteria instead of mammalian cells, which are needed for antibody production, Pieris said.

¿For the first time, there could be a true alternative to antibodies within the entire life science industry, which is striving for the development of novel protein therapeutics,¿ Pieris CEO Martin Poehlchen said in a prepared statement.

Anticalins are synthetic proteins derived from naturally occurring lipocalins. Lipocalins are proteins, which in the human body act as carriers for non-soluble molecules.

Pieris Chief Scientific Officer Steffen Schlehuber told BioWorld International, ¿Lipocalins are beta-barrel-like proteins, closed at one end and open to the solvent at the other side. On this side, four loops form a ligand-binding pocket. For the generation of synthetic anticalins that specifically recognize prescribed ligands, we choose amino acid positions throughout these four loops and subject them to random mutagenesis.¿

Thus, the firm¿s Theracalin Library of more than 10 billion different anticalin structures was built, each of them with another amino acid sequence in the loops.

Anticalins are single-chain polypeptides usually consisting of 150 to 190 amino acids. Being much smaller than antibodies, anticalins may penetrate tissues better, the company said.

Poehlchen said, ¿We have optimized the generation of anticalins to get high-affinity binders to a given target within days.¿

Pieris expects anticalins to act as antagonists or agonists on cell-surface targets.