1. Guest, the two part 'News in Brief' for the week beginning 22nd May 2023 is here.
    Dismiss Notice
  2. Welcome! To read the Core Purpose and Values of our forum, click here.
    Dismiss Notice

Pre-existing polymerase-specific T cells expand in abortive seronegative SARS-CoV-2, 2021, Leo Swadling et al

Discussion in 'Epidemics (including Covid-19, not Long Covid)' started by Sean, Dec 8, 2021.

  1. Sean

    Sean Senior Member (Voting Rights)

    Pre-existing polymerase-specific T cells expand in abortive seronegative SARS-CoV-2

    Leo Swadling, et al.

    Individuals with potential exposure to SARS-CoV-2 do not necessarily develop PCR or antibody positivity, suggesting some may clear sub-clinical infection before seroconversion.

    T-cells can contribute to the rapid clearance of SARS-CoV-2 and other coronavirus infections1-3. We hypothesised that pre-existing memory T-cell responses, with cross-protective potential against SARS-CoV-24-11, would expand in vivo to support rapid viral control, aborting infection.

    We measured SARS-CoV-2-reactive T-cells, including those against the early transcribed replication transcription complex (RTC)12,13, in intensively monitored healthcare workers (HCW) remaining repeatedly negative by PCR, antibody binding, and neutralisation (seronegative HCW, SN-HCW).

    SN-HCW had stronger, more multispecific memory T-cells than an unexposed pre-pandemic cohort, and more frequently directed against the RTC than the structural protein-dominated responses seen post-detectable infection (matched concurrent cohort).

    SN-HCW with the strongest RTC-specific T-cells had an increase in IFI27, a robust early innate signature of SARS-CoV-214, suggesting abortive infection.

    RNA-polymerase within RTC was the largest region of high sequence conservation across human seasonal coronaviruses (HCoV) and SARS-CoV-2 clades.

    RNA-polymerase was preferentially targeted (amongst regions tested) by T-cells from pre-pandemic cohorts and SN-HCW. RTC epitope-specific T-cells cross-recognising HCoV variants were identified in SN-HCW.

    Enriched pre-existing RNA-polymerase-specific T-cells expanded in vivo to preferentially accumulate in the memory response after putative abortive compared to overt SARS-CoV-2 infection.

    Our data highlight RTC-specific T-cells as targets for vaccines against endemic and emerging Coronaviridae.

  2. Snow Leopard

    Snow Leopard Senior Member (Voting Rights)

    How did they control for the level of exposure 'dosage'?

    The abortive infection could be in part due to a lower quantity of virus exposure in the first place - so a few T-cells could clean up the mess easily, whereas with a higher exposure dose that might not be possible.

Share This Page