Tetanus Neurotoxin Neutralizing Antibodies Screened from a Human Immune scFv Antibody Phage Display Library

Abstract

Tetanus neurotoxin (TeNT) produced by Clostridium tetani is one of the most poisonous protein substances. Neutralizing antibodies against TeNT can effectively prevent and cure toxicosis. Using purified Hc fragments of TeNT (TeNT-Hc) as an antigen, three specific neutralizing antibody clones recognizing different epitopes were selected from a human immune scFv antibody phage display library. The three antibodies (2-7G, 2-2D, and S-4-7H) can effectively inhibit the binding between TeNT-Hc and differentiated PC-12 cells in vitro. Moreover, 2-7G inhibited TeNT-Hc binding to the receptor via carbohydrate-binding sites of the W pocket while 2-2D and S-4-7H inhibited binding of the R pocket. Although no single mAb completely protected mice from the toxin, they could both prolong survival when challenged with 20 LD50s (50% of the lethal dose) of TeNT. When used together, the mAbs completely neutralized 1000 LD50s/mg Ab, indicating their high neutralizing potency in vivo. Antibodies recognizing different carbohydrate-binding pockets could have higher synergistic toxin neutralization activities than those that recognize the same pockets. These results could lead to further production of neutralizing antibody drugs against TeNT and indicate that using TeNT-Hc as an antigen for screening human antibodies for TeNT intoxication therapy from human immune antibody library was convenient and effective.

Identification of a Tetanus Toxin Specific Epitope in Single Amino Acid Resolution

“…[26,[31][32][33] The simultaneous binding of antibodies to ensure neutralization was described earlier. [13,34] The role of the identified epitope should be further investigated in neutralization studies.…”

Biological properties the novel application of N-trimethyl chitosan nanospheres as a stabilizer and preservative in tetanus vaccine

“…A 40% DQ makes N-TMC transport and deliver a variety of antigens and generate an optimum immune response. However, N-TMC by itself has no antigenic property and the immune system does not response against chitosan [ 31 ].…”

A Novel Single Domain Antibody Targeting FliC Flagellin of Salmonella enterica for Effective Inhibition of Host Cell Invasion

“…The field of antibody therapeutics has expanded significantly in the past decade, with a record number of antibody drugs (12) approved in 2018 (Kaplon and Reichert, 2018). Technological advances have been integral in the identification and development of several formats of antibody based biologics, from full length antibodies that bind to tumor necrosis factor for the treatment of inflammatory diseases (Humira ® , Salfeld et al, 1998; Alizadeh et al, 2015; Frenzel et al, 2016) to engineered fragments that neutralize neurotoxins produced by Clostridia (Miethe et al, 2014; Frenzel et al, 2016; Wang et al, 2016). Single domain antibodies (sdAbs) have become attractive molecules in therapeutic research.…”