Rational design of a Kv1.3 channel-blocking antibody as a selective immunosuppressant

Abstract

A variable region fusion strategy was used to generate an immunosuppressive antibody based on a novel "stalk-knob" structural motif in the ultralong complementary-determining region (CDR) of a bovine antibody. The potent Kv1.3 channel inhibitory peptides Moka1-toxin and Vm24-toxin were grafted into different CDRs of the humanized antibodies BVK and Synagis (Syn) using both β-sheet and coiled-coil linkers. Structure-activity relationship efforts led to generation of the fusion protein Syn-Vm24-CDR3L, which demonstrated excellent selectivity and potency against effector human memory T cells (subnanomolar to picomolar EC 50 values). This fusion antibody also had significantly improved plasma half-life and serum stability in rodents compared with the parent Vm24 peptide. Finally, this fusion protein showed potent in vivo efficacy in the delayed type hypersensitivity in rats. These results illustrate the utility of antibody CDR fusions as a general and effective strategy to generate long-acting functional antibodies, and may lead to a selective immunosuppressive antibody for the treatment of autoimmune diseases.antibody | protein engineering | Kv1.3 | autoimmune | immunosuppressive

A multiplatform strategy for the discovery of conventional monoclonal antibodies that inhibit the voltage-gated potassium channel Kv1.3

“…A number of groups have successfully generated anti-Kv1.3 immunoglobulins that inhibit channel activity, including polyclonal antibodies generated in rabbits, heavy chain only VHH nanobodies in llamas (US Patent Application 20170137512), and engineered cowbodies that incorporate inhibitory Kv1.3 toxins into the ultralong CDR that are characteristic of these antibodies. 33 , 34 However, to our knowledge, this study describes the first set of conventional mAbs capable of blocking the activity of human Kv1.3. To achieve this, we applied a general strategy designed to mitigate several of the challenges associated with the production of functional antibodies against human VGICs.…”

Ion channels as therapeutic antibody targets

“…The rational design of a bovine antibody has been used to generate a selective immunosuppressive mAb targeting K v 1.3. 359 This was achieved by grafting the toxin peptide sequences for Moka-1 toxin and Vm24-toxin into the ultralong bovine heavy chain complementarity-determining region 3 (CDR3). The resulting mAb, SVN-001, demonstrated good selectivity and potency against effector human T EM cells, a significantly improved plasma half-life and serum stability compared with the parent peptide, as well as potent in vivo efficacy.…”

“…The resulting mAb, SVN-001, demonstrated good selectivity and potency against effector human T EM cells, a significantly improved plasma half-life and serum stability compared with the parent peptide, as well as potent in vivo efficacy. 359 By targeting a unique subset of immune cells, SVN-001 is not broadly immunosuppressive, which improves the safety profile compared to typical immunosuppressants.…”

Antibodies Targeting KVPotassium Channels: A Promising Treatment for Cancer

“…An alternative approach is the fusion of known active peptides (i.e., toxins) to the complementarity-determining regions of a known antibody specific to a particular channel. This has been carried out successfully in the case of K V 1.3, 94 resulting in a more powerful blockade by the toxin, although it is still unclear if the selectivity achieved comes from the antibody, from the toxin or both.…”