A humanized anti-human adenovirus 55 monoclonal antibody with good neutralization ability

Abstract

BackgroundHuman adenovirus type 55 (HAdV55) has a re-emerged as pathogen causing an acute respiratory disease presenting as a severe lower respiratory illness that can cause death. To date, there is no HAdV55 vaccine or treatment available for general use.MethodsHerein, a monoclonal antibody specific for HAdV55, mAb 9-8, was isolated from an scFv-phage display library derived from mice immunized with the purified inactived-HAdV55 virions. By using ELISA and a virus micro-neutralization assay, we evaluated the binding and neutralizing activity of mAb 9-8 following humanization. Western blotting analysis and antigen-antibody molecular docking analysis were used to identify the antigenic epitopes that the humanized monoclonal antibody 9-8-h2 recognized. After that, their thermal stability was determined.ResultsMAb 9-8 showed potent neutralization activity against HAdV55. After humanization, the humanized neutralizing monoclonal antibody (9-8-h2) was identified to neutralize HAdV55 infection with an IC50 of 0.6050 nM. The mAb 9-8-h2 recognized HAdV55 and HAdV7 virus particles, but not HAdV4 particles. Although mAb 9-8-h2 could recognize HAdV7, it could not neutralize HAdV7. Furthermore, mAb 9-8-h2 recognized a conformational neutralization epitope of the fiber protein and the crucial amino acid residues (Arg 288, Asp 157, and Asn 200) were identified. MAb 9-8-h2 also showed favorable general physicochemical properties, including good thermostability and pH stability.ConclusionsOverall, mAb 9-8-h2 might be a promising molecule for the prevention and treatment of HAdV55.

Isolation and characterization of Hc-targeting chimeric heavy chain antibodies neutralizing botulinum neurotoxin type B

“…The characteristics of the pilot-scale Hc antigens were determined, and qualified recombinant protein batches were stored at −80 °C for further studies. THc is the Hc domain of Tetanus toxin and 7f is the fiber protein of adenovirus serotype 7, which were prepared by our laboratory as controls ( 32 , 33 ).…”

“…Specific primers were designed to obtain the nanobody fragments through two rounds of nested PCR. The obtained nanobody fragments were digested with Nco I/Not I and cloned into the ScFv-NEN expression phage vector ( 32 ). The recombinant phage was introduced into newly prepared E. coli TG1 competent cells via electroporation.…”