How Native-Like Recombinant Proteins Enable More Informative Antibody Discovery
Recombinant protein format matters throughout immunization antibody screening and development because protein sequences, folding, oligomeric state and receptor assembly determine which epitopes are presented. Formats that more closely reproduce the native target can preserve biologically relevant interaction surfaces and expose conformational or interface-dependent epitopes that may be absent from simplified monomeric proteins.
Using complementary formats provides additional insight across a program. Native-like complexes can serve as biologically relevant immunogens and screening reagents, while individual subunits can help map specificity and distinguish subunit-reactive antibodies from those that recognize epitopes formed or exposed only in the assembled complex. Successful antibody discovery starts with more than the right target—it starts with the right presentation of that target. Protein sequences, folding, oligomeric state, tags, and overall architecture can determine which epitopes are available during immunization and which antibodies advance during screening.
At Conigen, we engineer biologically relevant recombinant proteins designed to preserve the structural and functional features that matter for antibody discovery. Our native-like multimers, heteromeric complexes, individual subunits, and related constructs can be used together to support a more connected workflow—from generating diverse antibody responses to identifying candidates with the desired specificity and biological activity.
Supporting the Complete Antibody Discovery Workflow
Immunogen design: Native-like proteins can present subunit-specific, conformational, and interface-dependent epitopes, generating diverse antibodies during immunization.
Antibody screening: Consistent, well-characterized antigens enable reliable antibody identification and characterization.
Epitope differentiation: Structural complexes, individual subunits, and related conformations and epitopes can distinguish subunit-specific antibodies from those recognizing conformational or interface-dependent epitopes.
Binding characterization: These native-like proteins can be used for a wide range of antibody characterization workflow including ELISA, SPR, BLI, specificity mapping, and competition assays.
Functional evaluation: Bioactive proteins that recapitulate relevant ligand–receptor interactions enable functional screening of antibodies for their ability to block, enhance, or otherwise modulate target binding and receptor activity.
By engineering native-like proteins, Conigen helps researchers move beyond identifying antibodies that simply bind—and toward candidates with defined specificity, functional activity, and greater therapeutic or research potential.
Discovering Diverse Antibodies with a Native-Like IFNαR1/R2 Heterodimer
Native type I interferon receptor (IFNαR) is a heterodimer formed by two subunits, IFNαR1 and IFNαR2 on cell surfaces. Their extracellular domains work together to bind type I interferons and initiate downstream signaling. Because the functional receptor depends on this multicomponent architecture, isolated receptor subunits may not fully recapitulate the conformational and interface-dependent epitopes formed within the native receptor complex. To address this challenge, we designed a recombinant IFNαR1/R2 heterodimer that brings together the extracellular domains of both receptor subunits in a single construct. The protein incorporates the four-domain extracellular region of IFNαR1 and the two-domain extracellular region of IFNαR2, joined through an Fc-free heterodimerization motif.
This design offers several advantages for antibody discovery:
- It mimics the native receptor complex present on the cell surface.
- It is expressed and purified as a single heterodimeric unit, without post-purification assembly of the two receptor arms.
- Its compact, Fc-free format avoids unwanted Fc-mediated activity.
Outcome 1 – Enhanced Bioactivity
Before using the heterodimer as an immunogen, we characterized its biochemical integrity and binding activity.
SDS-PAGE under reducing and non-reducing conditions supported the recovery of the purified heterodimer as a single assembled protein. The heterodimer also retained recognition by a known IFNαR1 and IFNαR2-specific antibody.
Most importantly, the recombinant heterodimer demonstrated substantially enhanced binding to type I interferon compared with the individual IFNαR1 and IFNαR2 monomers in ELISA. Label-free SPR and BLI studies showed a similar overall binding trend. Together, these results supported the use of the heterodimer as a biologically relevant immunogen that more closely represents the functional receptor complex.
Outcome 2 – Greater Antibody Diversity
Immunization with the IFNαR1/R2 heterodimer produced a diverse panel of monoclonal antibodies. ELISA screening against the heterodimer and the individual receptor subunits identified three distinct specificity profiles:
- Heterodimer-specific antibodies: bind strongly to the IFNαR1/R2 heterodimer but not to either IFNαR1 or IFNαR2 isolated subunit. This pattern is consistent with recognition of conformational epitopes at the IFNαR1/R2 heterodimer interface.
- IFNαR1-specific antibodies: recognize both the heterodimer and the isolated IFNαR1 subunit.
- IFNαR2-specific antibodies: recognize both the heterodimer and the isolated IFNαR2 subunit.
Why Antigen Format Matters
This study demonstrates how a rationally designed recombinant protein can do more than provide a target for antibody generation. By presenting IFNαR1 and IFNαR2 together in a native-like configuration, the heterodimer enabled discovery of antibodies against three categories of epitopes: IFNαR1,IFNαR2, and heterodimer-dependent conformational epitopes.
The individual receptor IFNαR1,IFNαR2 monomers then served as complementary screening reagents, making it possible to classify each clone according to its binding specificity. The same protein panel could support subsequent characterization by ELISA, SPR, BLI, competition assays, and functional studies.
The result is an integrated discovery strategy in which recombinant proteins support every stage—from creating a biologically relevant immunogen to identifying, differentiating, and characterizing promising antibody candidates.
Build a More Informative Antibody Discovery Campaign
Whether the target is a single chain, a multi-subunit receptor, or a structurally complex antigen, the design, and quality of the recombinant protein can influence the antibodies a campaign is able to uncover.
Our portfolio of recombinant proteins and custom protein-development capabilities can support immunization, screening, epitope classification, binding analysis and functional characterization—helping researchers move from antigen design to actionable antibody candidates with confidence
Q&A
Why does recombinant protein format matter throughout immunization antibody screening and development?
Recombinant protein format matters throughout immunization antibody screening and development because protein sequences, folding, oligomeric state, and receptor assembly determine which epitopes are presented. Formats that more closely recapitulate the native target can preserve biologically relevant interaction surfaces and expose conformational or interface-dependent epitopes that may be absent from simplified monomeric proteins.
Using complementary formats provides additional insight across a program. Native-like complexes can serve as biologically relevant immunogens and screening reagents, while individual subunits can help map specificity and distinguish subunit-reactive antibodies from those that recognize epitopes formed or exposed only in the assembled complex.
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