AUTHOR=Bricio-Moreno Laura , Barreto de Albuquerque Juliana , Neary Jake M. , Nguyen Thao , Kuhn Lucy F. , Yeung YeePui , Hastie Kathryn M. , Landeras-Bueno Sara , Olmedillas Eduardo , Hariharan Chitra , Nathan Anusha , Getz Matthew A. , Gayton Alton C. , Khatri Ashok , Gaiha Gaurav D. , Ollmann Saphire Erica , Luster Andrew D. , Moon James J. 

TITLE=Identification of mouse CD4+ T cell epitopes in SARS-CoV-2 BA.1 spike and nucleocapsid for use in peptide:MHCII tetramers

JOURNAL=Frontiers in Immunology

VOLUME=15

YEAR=2024

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2024.1329846

DOI=10.3389/fimmu.2024.1329846

ISSN=1664-3224

ABSTRACT=<p>Understanding adaptive immunity against SARS-CoV-2 is a major requisite for the development of effective vaccines and treatments for COVID-19. CD4<sup>+</sup> T cells play an integral role in this process primarily by generating antiviral cytokines and providing help to antibody-producing B cells. To empower detailed studies of SARS-CoV-2-specific CD4<sup>+</sup> T cell responses in mouse models, we comprehensively mapped I-A<sup>b</sup>-restricted epitopes for the spike and nucleocapsid proteins of the BA.1 variant of concern via IFNγ ELISpot assay. This was followed by the generation of corresponding peptide:MHCII tetramer reagents to directly stain epitope-specific T cells. Using this rigorous validation strategy, we identified 6 immunogenic epitopes in spike and 3 in nucleocapsid, all of which are conserved in the ancestral Wuhan strain. We also validated a previously identified epitope from Wuhan that is absent in BA.1. These epitopes and tetramers will be invaluable tools for SARS-CoV-2 antigen-specific CD4<sup>+</sup> T cell studies in mice.</p>