Targets and cross-reactivity of human T cell recognition of common cold coronaviruses

Area of Science:

• Immunology
• Virology
• Vaccinology

Background:

• Coronaviruses (CoVs) pose significant public health threats, necessitating broad-spectrum vaccine strategies.
• Understanding T-cell responses to common cold CoVs (CCCs) can inform the development of pan-CoV vaccines.

Purpose of the Study:

• To analyze T-cell reactivity against common cold CoVs (Alpha-NL63 and Beta-OC43).
• To assess T-cell cross-reactivity against diverse CoV groups, including sarbecoCoVs.
• To identify key viral antigens and epitopes involved in T-cell responses.

Main Methods:

• Analysis of T-cell reactivity in pre-pandemic human samples against Alpha (NL63) and Beta (OC43) CoVs.
• Identification of immunodominant and virus-specific T-cell epitopes.
• Assessment of T-cell cross-reactivity against various CoV groups (AlphaCoV, sarbecoCoV, Beta-non-sarbecoCoV).

Main Results:

• S, N, M, and nsp3 antigens showed immunodominance, similar to SARS-CoV-2.
• nsp2 and nsp12 were specific to either Alpha or Beta CoVs.
• High T-cell cross-reactivity (>67% sequence conservation) was observed within Alpha and Beta groups.
• Limited cross-reactivity against sarbecoCoVs was noted, even with sequence conservation, suggesting prior CoV exposure is critical.

Conclusions:

• Pre-existing T-cell immunity against common cold CoVs contributes to cross-reactivity within homologous groups.
• Sequence conservation alone does not guarantee cross-reactivity, particularly for sarbecoCoVs.
• Findings provide crucial insights for designing effective pan-CoV vaccines targeting diverse human CoVs.