US Patent 7722871 Immunoglobulins devoid of light chains

The invention relates to an immunoglobulin having determined antigen specificity, and having a variable fragment which is obtainable from a camelid heavy-chain immunoglobulin having two heavy polypeptide chains capable of recognizing and binding an antigen and which is further devoid of polypeptide light chains, wherein the immunoglobulin having determined antigen specificity is devoid of a CH1 constant region between the variable region and the hinge region and has within its constant region at least part of a constant region of a human antibody.