Immunological Responses to Human Coronaviruses

Human coronaviruses elicit a complex interplay of innate and adaptive immune responses that determine clinical outcome, transmission dynamics and vaccine efficacy. Upon viral entry, pattern recognition receptors trigger interferon production, chemokine release and activation of macrophages and natural killer cells. The subsequent adaptive phase involves antibody generation by B cells and antiviral T-cell immunity, including CD4+ helper responses that support antibody class switching and CD8+ cytotoxic responses that eliminate infected cells. Neutralising antibodies against the viral spike protein, especially those targeting the receptor-binding domain and conserved S2 subunit, can block infection and contribute to herd immunity, while memory B cells and T cells underpin durable protection. Cross-reactive responses to seasonal human coronaviruses shape disease severity and vaccine responses through immunological imprinting, whereby prior exposure biases the specificity and magnitude of antibody and memory cell repertoires. Viral antigenic evolution, most notably within the spike protein, can erode neutralisation potency and demand vaccine updates. Understanding the balance between protective and potentially pathogenic responses, such as dysregulated cytokine release, is essential for the design of pancoronavirus vaccines and immunomodulatory therapies with global impact.

Research from Nature Portfolio

Systematic analyses of antibody kinetics across human coronaviruses have defined correlates of protection and highlighted waning of neutralising titres within months of infection or vaccination, reinforcing the need for booster strategies and next-generation vaccine antigens. Detailed studies of spike-reactive memory B cells reveal that cross-reactive clones, particularly those recognising the conserved S2 subunit, are expanded upon SARS-CoV-2 infection, suggesting avenues for broad protection against diverse strains. Investigations into immunological imprinting demonstrate that back-boosting of seasonal coronavirus-specific antibodies occurs upon SARS-CoV-2 challenge yet may inversely correlate with de novo responses to novel epitopes, underscoring the importance of antigen design that overcomes pre-existing biases.

Immunological Responses to Human Coronaviruses publication trend

The graph below shows the total number of articles in immunological responses to human coronaviruses across all publications each year (not limited to Nature Index journals).

Technical terms

Neutralising antibody: An antibody that binds to viral surface proteins and blocks entry into host cells, preventing infection.

Memory B cell: A long-lived B lymphocyte that rapidly produces specific antibodies upon re-exposure to its cognate antigen.

Immunological imprinting: The phenomenon whereby prior exposure to related antigens shapes the specificity and magnitude of subsequent immune responses.

Cross-reactivity: The capacity of an immune receptor or antibody to recognise similar epitopes on different, but related, viral strains.

S1/S2 subunits: Functional domains of the coronavirus spike protein; S1 contains the receptor-binding domain, while S2 mediates membrane fusion and contains conserved regions targeted by broadly reactive antibodies.

References

1. A systematic review of antibody mediated immunity to coronaviruses: kinetics, correlates of protection, and association with severity. Nature Communications (2020).
2. S Protein-Reactive IgG and Memory B Cell Production after Human SARS-CoV-2 Infection Includes Broad Reactivity to the S2 Subunit. mBio (2020).
3. Immunological imprinting of the antibody response in COVID-19 patients. Nature Communications (2021).
4. Impact of ageing on homologous and human-coronavirus-reactive antibodies after SARS-CoV-2 vaccination or infection. npj Vaccines (2024).
5. Antibody and B Cell Responses to SARS-CoV-2 Infection and Vaccination: The End of the Beginning. Annual Review of Pathology Mechanisms of Disease (2023).
6. Assessment of Broadly Reactive Responses in Patients With MERS-CoV Infection and SARS-CoV-2 Vaccination. JAMA Network Open (2023).