J Leukoc Biol . Cross-reactive cellular, but not humoral, immunity is detected between OC43 and SARS-CoV-2 NPs in people not infected with SARS-CoV-2: Possible role of cT FH cells

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J Leukoc Biol


. 2022 Apr 5.
doi: 10.1002/JLB.4COVCRA0721-356RRR. Online ahead of print.
Cross-reactive cellular, but not humoral, immunity is detected between OC43 and SARS-CoV-2 NPs in people not infected with SARS-CoV-2: Possible role of cT _FH cells


Álvaro Fernando García-Jiménez ¹ , Yaiza Cáceres-Martell ¹ , Daniel Fernández-Soto ¹ , Pedro Martínez Fleta ² , José M Casasnovas ³ , Francisco Sánchez-Madrid ² , José Miguel Rodríguez Frade ¹ , Mar Valés-Gómez ¹ , Hugh T Reyburn ¹



Affiliations

• PMID: 35384035
• DOI: 10.1002/JLB.4COVCRA0721-356RRR

Abstract

Multiple questions about SARS-CoV-2 humoral and cellular immunity remain unanswered. One key question is whether preexisting memory T or B cells, specific for related coronaviruses in SARS-CoV-2-unexposed individuals, can recognize and suppress COVID-19, but this issue remains unclear. Here, we demonstrate that antibody responses to SARS-CoV-2 antigens are restricted to serum samples from COVID-19 convalescent individuals. In contrast, cross-reactive T cell proliferation and IFN-γ production responses were detected in PBMCs of around 30% of donor samples collected prepandemic, although we found that these prepandemic T cell responses only elicited weak cT_FH activation upon stimulation with either HCoV-OC43 or SARS-CoV-2 NP protein. Overall, these observations confirm that T cell cross-reactive with SARS-CoV-2 antigens are present in unexposed people, but suggest that the T cell response to HCoV-OC43 could be deficient in some important aspects, like T_FH expansion, that might compromise the generation of cross-reactive T_FH cells and antibodies. Understanding these differences in cellular responses may be of critical importance to advance in our knowledge of immunity against SARS-CoV-2.

Keywords: COVID-19; HCoV-OC43; SARS-CoV-2; cross-reactive immunity.