Built‐in RNA‐mediated chaperone (chaperna) for antigen folding tailored to immunized hosts

Abstract

High-quality antibody (Ab) production depends on the availability of immunologically relevant antigens. We present a potentially universal platform for generating soluble antigens from bacterial hosts, tailored to immunized animals for Ab production. A novel RNA-dependent chaperone, in which the target antigen is genetically fused with an RNA-interacting domain (RID) docking tag derived from the immunized host, promotes the solubility and robust folding of the target antigen. We selected the N-terminal tRNA-binding domain of lysyl-tRNA synthetase (LysRS) as the RID for fusion with viral proteins and demonstrated the expression of the RID fusion proteins in their soluble and native conformations; immunization predominantly elicited Ab responses to the target antigen, whereas the "self" RID tag remained nonimmunogenic. Differential immunogenicity of the fusion proteins greatly enriched and simplified the screening of hybridoma clones of monoclonal antibodies (mAbs), enabling specific and sensitive serodiagnosis of MERS-CoV infection. Moreover, mAbs against the consensus influenza hemagglutinin stalk domain enabled a novel assay for trivalent seasonal influenza vaccines. The Fc-mediated effector function was demonstrated, which could be harnessed for the design of next-generation "universal" influenza vaccines. The nonimmunogenic built-in antigen folding module tailored to a repertoire of immunized animal hosts will drive immunochemical diagnostics, therapeutics, and designer vaccines.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

TAR RNA Mediated Folding of a Single-Arginine-Mutant HIV-1 Tat Protein within HeLa Cells Experiencing Intracellular Crowding

“…These aspects could be extended to the supramolecular aggregates of genetically mutable viral diseases that have caused pandemics such as COVID-19, indicating that they should be considered for enhancing immunogenicity [ 79 , 80 ]. Therefore, our findings further enhance our understanding of the as-yet-unexplored viral-encoding chaperna that interacts with intracellular factors during cellular crowding [ 77 ]. The relative stability of the IDPs interacting with RNA-mediated folding and the therapeutic function of disease modulators linked to the development of drug-delivery applications need to be further investigated.…”

“…These properties of RNA can stabilize intermediate folding and interfere with protein aggregation. This suggests that, although our understanding of the roles of various molecular chaperones is still limited, as the important role of virally encoded RNA in establishing proteome linkages is considered, there may be a variety of viral-encoding chaperones that have not yet been characterized [ 77 , 78 ].…”

Comparative Evaluation of Recombinant and Acellular Pertussis Vaccines in a Murine Model

“…A growing need for new vaccine modality, we evaluated the recombinant raP antigens produced from E. coli compared with aP antigens purified from B. pertussis in this study. To overcome misfolding into immunologically irrelevant inclusion bodies in E. coli host, a novel chaperna approach was undertaken to increase the proper folding and the solubility of recombinant antigens [ 36 , 37 , 38 ]. aP components were combined with diphtheria (D) and tetanus (T) toxoids into DTaP trivalent vaccine, and the immunogenicity and the protective efficacy of raP and aP were compared in an experimental murine immunization and challenge model using Infanrix TM as a comparator vaccine (control).…”

“…The recombinant DTaP vaccine consists of GC Pharma’s diphtheria and tetanus toxoids (same concentration of GC DTaP), and three components of raP vaccine antigens produced by a WHEP vector ( Figure 2 a), developed at Yonsei University. WHEP domain derived from human glutamyl prolyl tRNA synthetase (hEPRS) was chosen as a fusion partner for exerting chaperna function [ 36 , 37 , 38 ] to expedite folding and soluble expression in E. coli . Thus, all three antigens-pertussis toxin subunit 1 (PtxS1), filamentous hemagglutinin (FHA), and pertactin (PRN) domains, respectively, were genetically fused with WHEP domain and expressed as soluble form, purified by Ni-affinity chromatography following similar protocol for purification ( Figure 2 b) [ 35 ].…”

“…Despite conflicting results, secretory IgA from the mucosal surface of the respiratory tract, mediated by IL-17a, reduces pertussis colonization and promotes long-term immunity [ 32 , 33 ]. Recent technical innovations on protein folding platforms are being tested for recombinant vaccines against a variety of infectious diseases [ 34 , 35 , 36 , 37 , 38 ]. This prompted us to develop and evaluate recombinant pertussis vaccine antigens from bacterial hosts as a potential alternative to previously developed aP vaccines.…”