A process is provided for the production of an
antibody or a fragment or functionalized fragment thereof using a transformed lower eukaryotic host containing an example
DNA sequence encoding the
antibody or (functionalized) fragment thereof, wherein the
antibody or (functionalized) fragment thereof is derived from a
heavy chain immunoglobulin of Camelidae and is devoid of light chains, and wherein the lower eukaryotic host is a mould, preferably belonging to the genera
Aspergillus or
Trichoderma, or a
yeast, preferably belonging to the
yeast genera
Saccharomyces,
Kluyveromyces, Hansenula, or
Pichia. The
heavy chain fragment can contain at least the whole
variable domain. A complementary determining region (CDR) different from the CDR belonging to the
natural antibody ex Camelidae can be grafted on the framework of the
variable domain of the
heavy chain immunoglobulin. The catalytic antibodies can be raised in Camelidae against
transition state molecules. The functionalized antibody or fragment thereof can comprise a
fusion protein of both a heavy chain immunoglobulin from Camelidae or a fragment thereof and another polypeptide, e.g., an
enzyme, preferably an oxido-
reductase. Also provided are new products obtainable by a process as described, and compositions containing a product produced by a process as described, which composition may contain a new product as provided.