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ORIGINAL RESEARCH article

Front. Immunol.

Sec. Vaccines and Molecular Therapeutics

Different Fc scaffolds enhance the breadth of in vitro neutralization of the same Fab against different Rotavirus strains

Provisionally accepted
Giacomo  VezzaniGiacomo Vezzani1*Mabel Miranda Rocio  EchagueMabel Miranda Rocio Echague2Elena  MorandiElena Morandi1Melania  Della PerutaMelania Della Peruta1Mirko  ScordioMirko Scordio1Teresa Anne Clarisse  ReyesTeresa Anne Clarisse Reyes1Davide  OldriniDavide Oldrini1Miren  Iturriza-GómaraMiren Iturriza-Gómara1Rebecca  Jo LoomisRebecca Jo Loomis1Omar  RossiOmar Rossi1
  • 1GSK Vaccines Institute for Global Health, Siena, Italy
  • 2Fondazione Biotecnopolo di Siena, Siena, Italy

The final, formatted version of the article will be published soon.

Rotaviruses are the primary cause of severe dehydrating diarrhea in infants and young children globally. Currently, several oral rotavirus vaccines are available; however, they have shown reduced effectiveness and quicker waning of protection in low-and middle-income countries (LMICs) compared to high-income countries (HICs). Both neutralizing and non-neutralizing antibodies against the middle (VP6) and outer layer capsid proteins (VP4 and VP7) are detected after infection, with higher titers being linked to disease protection. Historically, human derived rotavirus-specific monoclonal antibodies (mAbs) have been produced in an IgG1 scaffold, irrespective of whether their native scaffold was IgG or IgA. To explore the impact of antibody scaffolds on their functional activity we expressed mAbs targeting epitopes on VP8* or VP7 viral proteins in IgG1, IgG2, IgG3, IgG4, IgA1, and IgA2 scaffolds (the latter either in a monomeric or in a dimeric IgA form). The mAbs were characterized for their binding affinity to the viral target and their functionality was evaluated in an in vitro neutralization assay using three different rotavirus strains (G1P[8], G2P[4], and G9P[8]), representing homologous and heterologous specificities. Our findings revealed that mAbs targeting the same epitope exhibited varying neutralization activities when expressed in different scaffolds and suggested an enhanced breadth of neutralization activity in the context of an IgA scaffold. These data suggest that scaffolds impact the ability of antibodies to neutralize rotavirus. These findings can assist vaccine design informing the use of different technologies or adjuvants to elicit more effective antibody classes and subclasses.

Keywords: immunology, mAbs scaffold, Neutralization assay, Rotavirus, Vaccines

Received: 19 Sep 2025; Accepted: 15 Dec 2025.

Copyright: © 2025 Vezzani, Echague, Morandi, Della Peruta, Scordio, Reyes, Oldrini, Iturriza-Gómara, Loomis and Rossi. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence: Giacomo Vezzani

Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.