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1.
Nat Commun ; 13(1): 1251, 2022 03 10.
Article in English | MEDLINE | ID: covidwho-1740439

ABSTRACT

The trajectories of acquired immunity to severe acute respiratory syndrome coronavirus 2 infection are not fully understood. We present a detailed longitudinal cohort study of UK healthcare workers prior to vaccination, presenting April-June 2020 with asymptomatic or symptomatic infection. Here we show a highly variable range of responses, some of which (T cell interferon-gamma ELISpot, N-specific antibody) wane over time, while others (spike-specific antibody, B cell memory ELISpot) are stable. We use integrative analysis and a machine-learning approach (SIMON - Sequential Iterative Modeling OverNight) to explore this heterogeneity. We identify a subgroup of participants with higher antibody responses and interferon-gamma ELISpot T cell responses, and a robust trajectory for longer term immunity associates with higher levels of neutralising antibodies against the infecting (Victoria) strain and also against variants B.1.1.7 (alpha) and B.1.351 (beta). These variable trajectories following early priming may define subsequent protection from severe disease from novel variants.


Subject(s)
COVID-19 , SARS-CoV-2 , Antibodies, Viral , Antiviral Agents , Humans , Longitudinal Studies , Spike Glycoprotein, Coronavirus
2.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-322827

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is normally controlled by effective host immunity including innate, humoral and cellular responses. However, the trajectories and correlates of acquired immunity, and the capacity of memory responses months after infection to neutralise variants of concern - which has important public health implications - is not fully understood. To address this, we studied a cohort of 78 UK healthcare workers who presented in April to June 2020 with symptomatic PCR-confirmed infection or who tested positive during an asymptomatic screening programme and tracked virus-specific B and T cell responses longitudinally at 5-6 time points each over 6 months, prior to vaccination. We observed a highly variable range of responses, some of which - T cell interferon-gamma (IFN-γ) ELISpot, N-specific antibody waned over time across the cohort, while others (spike-specific antibody, B cell memory ELISpot) were stable. In such cohorts, antiviral antibody has been linked to protection against re-infection. We used integrative analysis and a machine-learning approach (SIMON - Sequential Iterative Modeling Over Night) to explore this heterogeneity and to identify predictors of sustained immune responses. Hierarchical clustering defined a group of high and low antibody responders, which showed stability over time regardless of clinical presentation. These antibody responses correlated with IFN-γ ELISpot measures of T cell immunity and represent a subgroup of patients with a robust trajectory for longer term immunity. Importantly, this immune-phenotype associates with higher levels of neutralising antibodies not only against the infecting (Victoria) strain but also against variants B.1.1.7 (alpha) and B.1.351 (beta). Overall memory responses to SARS-CoV-2 show distinct trajectories following early priming, that may define subsequent protection against infection and severe disease from novel variants.

3.
EuropePMC; 2021.
Preprint in English | EuropePMC | ID: ppcovidwho-308569

ABSTRACT

Global pandemics by influenza or coronaviruses cause severe disruptions to the public health and lead to severe morbidity and mortality. Vaccines against these pathogens remain a medical need. CMV (cytomegalovirus) is a β-herpesvirus that induces uniquely robust immune responses, where outstandingly large populations of antigen-specific CD8+ T cells are maintained for a lifetime. Hence, CMV has been proposed and investigated as a novel vaccine vector expressing antigenic peptides or proteins to elicit protective cellular immune responses against numerous pathogens. We generated two recombinant murine CMV (MCMV) vaccine vectors expressing the hemagglutinin (HA) of influenza A virus (MCMVHA) or the spike protein of the severe acute respiratory syndrome coronavirus 2 (MCMVS). A single shot of MCMVs expressing either viral protein induced potent neutralizing antibody responses, which strengthened over time. Importantly, MCMVHA vaccinated mice were protected from illness following challenge with the influenza virus, and we excluded that this protection was due to effects of memory T cells. Conclusively, we show here that MCMV vectors do not only induce long-term cellular immunity, but also humoral responses that provide long-term immune protection against clinically relevant respiratory pathogens.

4.
Cell Mol Immunol ; 19(2): 234-244, 2022 02.
Article in English | MEDLINE | ID: covidwho-1612184

ABSTRACT

Global pandemics caused by influenza or coronaviruses cause severe disruptions to public health and lead to high morbidity and mortality. There remains a medical need for vaccines against these pathogens. CMV (cytomegalovirus) is a ß-herpesvirus that induces uniquely robust immune responses in which remarkably large populations of antigen-specific CD8+ T cells are maintained for a lifetime. Hence, CMV has been proposed and investigated as a novel vaccine vector for expressing antigenic peptides or proteins to elicit protective cellular immune responses against numerous pathogens. We generated two recombinant murine CMV (MCMV) vaccine vectors expressing hemagglutinin (HA) of influenza A virus (MCMVHA) or the spike protein of severe acute respiratory syndrome coronavirus 2 (MCMVS). A single injection of MCMVs expressing either viral protein induced potent neutralizing antibody responses, which strengthened over time. Importantly, MCMVHA-vaccinated mice were protected from illness following challenge with the influenza virus, and we excluded that this protection was due to the effects of memory T cells. Conclusively, we show here that MCMV vectors induce not only long-term cellular immunity but also humoral responses that provide long-term immune protection against clinically relevant respiratory pathogens.


Subject(s)
COVID-19 Vaccines/immunology , COVID-19/prevention & control , Hemagglutinin Glycoproteins, Influenza Virus/immunology , Immunity, Humoral , Influenza A virus/immunology , Influenza Vaccines/immunology , Orthomyxoviridae Infections/prevention & control , SARS-CoV-2/immunology , Spike Glycoprotein, Coronavirus/immunology , Vaccination/methods , Animals , Antibodies, Neutralizing/blood , Antibodies, Neutralizing/immunology , Antibodies, Viral/blood , Antibodies, Viral/immunology , COVID-19/virology , Chlorocebus aethiops , Cytomegalovirus/immunology , Dogs , Female , HEK293 Cells , Humans , Immunity, Cellular , Madin Darby Canine Kidney Cells , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Orthomyxoviridae Infections/virology , Vero Cells
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