Scientists of Creative Biolabs have successfully built up a unique platform to develop high affinity bovine monoclonal antibodies with ultralong CDR3s.
The complementarity determining regions (CDRs) are most important structure parts on an antibody that recognize the antigen. In humans, the specificity of an antibody is mostly governed by the largest CDR, i.e. CDR H3. Compared with antibodies from other species, bovine antibodies are unusual in having exceptionally long CDR H3 loops; about 10% of bovine antibodies have ultralong CD3 H3 regions (35-60 AAs). Evidence has shown that antibodies with unusually long CDR H3 regions may be more effective in defense against disease than typical antibodies.
Fig. 1 Comparison between Human antibody and bovine antibody.
Bioinformatic analysis of ultralong CDR3s in bovine antibodies reveals a remarkable complexity of cysteines, which enables these ultralong CDR H3s to fold into a diversity of minidomains. Correspondingly, crystal structure reveals that these CDR H3s form a very unusual architecture composed of a β strand "stalk" that supports a structurally diverse, disulfide-bonded "knob" domain that can be elicited to recognize defined antigens.
With such unique structural and functional property, these bovine antibodies hold great potential on those targets that haven't been successfully targeted by traditional antibodies, for example, the GPCRs, and thus provide new avenues for therapeutic antibody development.
Besides developing bovine antibodies with ultralong CDR3s, Creative Biolabs has also established a technology to raise human therapeutic antibodies with ultralong CDR3s.