Immunology

Buggert and colleagues provide a phenotypic and functional map of SARS-CoV-2-specific
T cells across the full spectrum of exposure, infection, and COVID-19 severity. They
observe that SARS-CoV-2-specific T cells generate a broad, robust and functionally
replete response in convalescent individuals, that may provide protection from recurrent
episodes of severe COVID-19.

Covid-19 T cell response is strong 

Recent studies have provided insights into the pathogenesis of coronavirus disease 2019 (COVID-19)1–4. Yet, longitudinal immunological correlates of disease outcome remain unclear. Here, we serially analysed immune responses in 113 COVID-19 patients with moderate (non-ICU) and severe (ICU) disease. Immune profiling revealed an overall increase in innate cell lineages with a concomitant reduction in T cell number. We identify an association between early, elevated cytokines and worse disease outcomes. Following an early increase in cytokines, COVID-19 patients with moderate disease displayed a progressive reduction in type-1 (antiviral) and type-3 (antifungal) responses. In contrast, patients with severe disease maintained these elevated responses throughout the course of disease. Moreover, severe disease was accompanied by an increase in multiple type 2 (anti-helminths) effectors including, IL-5, IL-13, IgE and eosinophils. Unsupervised clustering analysis identified 4 immune signatures, representing (A) growth factors, (B) type-2/3 cytokines, (C) mixed type-1/2/3 cytokines, and (D) chemokines that correlated with three distinct disease trajectories of patients. The immune profile of patients who recovered with moderate disease was enriched in tissue reparative growth factor signature (A), while the profile for those with worsened disease trajectory had elevated levels of all four signatures. Thus, we identified development of a maladapted immune response profile associated with severe COVID-19 outcome and early immune signatures that correlate with divergent disease trajectories.

IgG anti-covid!

Extrapulmonary.... Click here to edit the content

T cell reactivity against SARS-CoV-2 was observed in unexposed people; however, the source and clinical relevance of the reactivity remains unknown. It is speculated that this reflects T cell memory to circulating ‘common cold’ coronaviruses. It will be important to define specificities of these T cells and assess their association with COVID-19 disease severity and vaccine responses. Recent studies have shown T cell reactivity to SARS-CoV-2 in 20–50% of unexposed individuals; it is speculated that this is due to T cell memory to common cold coronaviruses. Here, Crotty and Sette discuss the potential implications of these findings for disease severity, herd immunity and vaccine development.

interferons I and III

INTERFERON TYPE 1 and COVID-19

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bioRxiv - the preprint server for biology, operated by Cold Spring Harbor Laboratory, a research and educational institution

Abstract. Beside the commonly described pulmonary expression of the coronavirus disease 2019 (COVID-19), major vascular events have been reported. The objectiv

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused the rapidly unfolding coronavirus disease 2019 (COVID-19) pandemic1,2. Clinical manifestations of COVID-19 vary, ranging from asymptomatic infection to respiratory failure. The mechanisms determining such variable outcomes remain unresolved. Here, we investigated SARS-CoV-2 spike glycoprotein (S)-reactive CD4+ T cells in peripheral blood of patients with COVID-19 and SARS-CoV-2-unexposed healthy donors (HD). We detected SARS-CoV-2 S-reactive CD4+ T cells in 83% of patients with COVID-19 but also in 35% of HD. S-reactive CD4+ T cells in HD reacted primarily to C-terminal S epitopes, which show a higher homology to spike glycoproteins of human endemic coronaviruses, compared to N-terminal epitopes. S-reactive T cell lines generated from SARS-CoV-2-naive HD responded similarly to C-terminal S of human endemic coronaviruses 229E and OC43 and SARS-CoV-2, demonstrating the presence of S-cross-reactive T cells, probably generated during past encounters with endemic coronaviruses. The role of pre-existing SARS-CoV-2 cross-reactive T cells for clinical outcomes remains to be determined in larger cohorts. However, the presence of S-cross-reactive T cells in a sizable fraction of the general population may affect the dynamics of the current pandemic, and has important implications for the design and analysis of upcoming COVID-19 vaccine trials.

SARS-CoV-2 T cell immunity: Specificity, function, durability, and role in protection

T cells at last

bioRxiv - the preprint server for biology, operated by Cold Spring Harbor Laboratory, a research and educational institution

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