The discovery and evolution of antibody formats As antibody therapeutics evolve, new formats such as bispecific antibodies (bsAbs) and Fab fragments offer new and exciting therapeutic opportunities. However, traditional mAb isolation methods are often ineffective, necessitating innovative solutions. This article explores these challenges and introduces Astrea Bioseparations’ MiMode™ PuraBead® HX2 as an alternative strategy for isolating next-generation antibodies.
Antibody-based therapeutics have transformed modern medicine, offering targeted treatments for a range of diseases, including cancer, autoimmune disorders, and infectious diseases. Traditional monoclonal antibodies (mAbs) have been the backbone of this therapeutic class, however, advances in protein engineering have led to the development of various antibody formats, including Fab fragments, singlechain variable fragments (scFvs), and bispecific antibodies. These new formats aim to enhance efficacy, reduce immunogenicity, and improve manufacturability. Bispecific antibodies (bsAbs) are designed and engineered to recognize and bind two different antigens simultaneously. This dual specificity allows them to “bridge” immune cells interactions to tumor cells and, for example, deliver payloads
FV VL Fab
VH CL
with high precision. bsAbs have gained significant attention in oncology, particularly for their ability to engage T cells to kill tumor cells. These molecules are also being explored for applications in autoimmune diseases and infectious diseases, where they can modulate immune responses or neutralize multiple viral targets concurrently. Fab fragments, a type of fragmented antibody, are smaller, antigen-binding antibody fragments consisting of one constant and one variable domain from both heavy and light chains. Unlike full-length mAbs, Fab fragments lack the Fc (fragment crystallizable) region, which reduces their size and allows for improved tissue penetration. This characteristic makes Fab fragments particularly attractive for therapeutic applications where rapid distribution and clearance are desirable.
Fragmented Ab
CH1
Fab
scFv
BiTE
CrossMab
CH2 FC CH3
Bispecific Ab Full-length IgG
DVD-IgG
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