AUTHOR=Ishina Irina A. , Kurbatskaia Inna N. , Mamedov Azad E. , Shramova Elena I. , Deyev Sergey M. , Nurbaeva Kamila S. , Rubtsov Yury P. , Belogurov Alexey A. , Gabibov Alexander G. , Zakharova Maria Y. TITLE=Genetically engineered CD80–pMHC-harboring extracellular vesicles for antigen-specific CD4+ T-cell engagement JOURNAL=Frontiers in Bioengineering and Biotechnology VOLUME=11 YEAR=2024 URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2023.1341685 DOI=10.3389/fbioe.2023.1341685 ISSN=2296-4185 ABSTRACT=

The identification of low-frequency antigen-specific CD4+ T cells is crucial for effective immunomonitoring across various diseases. However, this task still encounters experimental challenges necessitating the implementation of enrichment procedures. While existing antigen-specific expansion technologies predominantly concentrate on the enrichment of CD8+ T cells, advancements in methods targeting CD4+ T cells have been limited. In this study, we report a technique that harnesses antigen-presenting extracellular vesicles (EVs) for stimulation and expansion of antigen-specific CD4+ T cells. EVs are derived from a genetically modified HeLa cell line designed to emulate professional antigen-presenting cells (APCs) by expressing key costimulatory molecules CD80 and specific peptide–MHC-II complexes (pMHCs). Our results demonstrate the beneficial potent stimulatory capacity of EVs in activating both immortalized and isolated human CD4+ T cells from peripheral blood mononuclear cells (PBMCs). Our technique successfully expands low-frequency influenza-specific CD4+ T cells from healthy individuals. In summary, the elaborated methodology represents a streamlined and efficient approach for the detection and expansion of antigen-specific CD4+ T cells, presenting a valuable alternative to existing antigen-specific T-cell expansion protocols.