Immune T cell defense is coping with COVID-19 variants of concern (for now)

Immune T cell defense is coping with COVID-19 variants of concern for now
CD4+ T cell response to SARS-CoV-2. a, Representative Elispot assays for the production on IFN-γ in whole and CD8PBMCs isolated from HCW-PI, plated at 2 × 105 cells per well and incubated with mixes of 15 aa peptides (overlapping by 11 aa) from SARS-CoV-2 S1, S2, M and N proteins, control (Ctrl) HLAI and HLAII epitope mixes and DMSO solvent (Neg). b, Summary of Elispot assays for the production of IFN-γ in whole versus CD8PBMCs using n = 10 HCW-PI incubated with peptide mixes as in a. Results are shown as mean SFC per 106 PBMCs. Significance was determined by two-sided Wilcoxon test, *P < 0.05. c, Summary of Elispot assays for the production of IFN-γ in CD8PBMCs from HCW-PI (n = 20) and UH (n = 14) individuals incubated with peptide mixes as in a. Results are shown as mean SFC per 106 CD8PBMCs. Significance was determined by two-sided Mann–Whitney U-test, **P < 0.01. d, Summary of ELISAs measuring IFN-γ production by polyclonal CD4+ T cell lines generated by initial stimulation of CD8PBMCs with peptide mixes as in a, then stimulated 7–14 days later with individual 20mer peptides (overlapping by 10 aa) spanning the relevant SARS-CoV-2 protein. Individual rows show the response from HCW-PI, n = 11. NS, not significant. Credit: Nature Immunology (2022). DOI: 10.1038/s41590-022-01351-7

Immune T cells are continuing to target the spike protein of SARS-CoV-2 variants of concern, although mutations are making some T cells less effective, according to new research.

Published in Nature Immunology, researchers from the University of Birmingham have shown that human T cell immunity is currently coping with mutations that have accumulated over time in COVID-19 variants.

In the study, the researchers tested CD4+ T cells collected at the start of the pandemic from health care workers infected with COVID-19.

Some of the T-cells were still able to recognize parts of the spike protein, called epitopes, unaltered in later virus strains including the current Omicron variant. However, T cell recognition was worse against seven out of ten epitopes mutated in different variants of concern.

The researchers caution that as SARS-CoV-2 continues to mutate, T-cell recognition of additional could be lost decreasing overall protection by the immune system.

Dr. Heather Long, Associate Professor in the Institute of Immunology and Immunotherapy at the University of Birmingham and lead author of the research said, "Our paper shows that although most people have a diverse T cell response against the virus, some responses are less effective against Omicron. As further variants of concern are identified we will need to consider carefully how new viral mutations affect T-cell recognition."

Dr. Graham Taylor, Associate Professor in the Institute of Immunology and Immunotherapy at the University of Birmingham said, "The vaccines currently in use are still vital to protect us from COVID-19. Should SARS-CoV-2 continue to mutate to evade the , our findings will help researchers to develop new vaccines better suited to those variants."

More information: Heather Long et al, Mutations in SARS-CoV-2 spike protein impair epitope-specific CD4+ T cell recognition, Nature Immunology (2022). DOI: 10.1038/s41590-022-01351-7

Journal information: Nature Immunology

Citation: Immune T cell defense is coping with COVID-19 variants of concern (for now) (2022, December 1) retrieved 8 February 2023 from https://medicalxpress.com/news/2022-12-immune-cell-defense-coping-covid-.html
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