Biology subjects

Gredmark-Russ, S.

Publications and source records attributed to Gredmark-Russ, S..

4 recordsLinked to original sources

bioRxiv2021

Longitudinal characterization of humoral and cellular immunity in hospitalized COVID-19 patients reveal immune persistence up to 9 months after infection

BackgroundInsights into early, specific humoral and cellular responses to infection with SARS-CoV-2, as well as the persistence and magnitude of resulting immune memory is important amidst the ongoing pandemic. The combination of humoral and cellular immunity will most likely contribute to protection from reinfection or severe disease. MethodsHere, we conducted a longitudinal study on hospitalized moderate and severe COVID-19 patients from the acute phase of disease into convalescence at five- and nine-months post symptom onset. Utilizing flow cytometry, serological assays as well as B cell and T cell FluoroSpot assays, we assessed the magnitude and specificity of humoral and cellular immune memory during and after human SARS-CoV-2 infection. FindingsDuring acute COVID-19, we observed an increase in germinal center activity, a substantial expansion of antibodysecreting cells, and the generation of SARS-CoV-2-neutralizing antibodies. Despite gradually decreasing antibody levels, we show persistent, neutralizing antibody titers as well as robust specific memory B cell responses and polyfunctional T cell responses at five- and nine-months after symptom onset in both moderate and severe COVID-19 patients. Long-term SARS-CoV-2 specific responses were marked by preferential targeting of spike over nucleocapsid protein. ConclusionsOur findings describe the initiation and, importantly, persistence of cellular and humoral SARS-CoV-2 specific immunological memory in hospitalized COVID-19 patients long after recovery, likely contributing towards protection against reinfection.

immunology↗

bioRxiv2021

Distinct lung-homing receptor expression and activation profiles on NK cell and T cell subsets in COVID-19 and influenza

Respiratory viral infections with SARS-CoV-2 or influenza viruses commonly induce a strong infiltration of immune cells into the lung, with potential detrimental effects on the integrity of the lung tissue. Despite comprising the largest fractions of circulating lymphocytes in the lung, little is known about how blood natural killer (NK) cells and T cell subsets are equipped for lung-homing in COVID-19 and influenza. Using 28-colour flow cytometry and re-analysis of published RNA-seq datasets, we provide a detailed comparative analysis of NK cells and T cells in peripheral blood from moderately sick COVID-19 and influenza patients, focusing on the expression of chemokine receptors known to be involved in leukocyte recruitment to the lung. The results reveal a predominant role for CXCR3, CXCR6, and CCR5 in COVID-19 and influenza patients, mirrored by scRNA-seq signatures in peripheral blood and bronchoalveolar lavage from publicly available datasets. NK cells and T cells expressing lung-homing receptors displayed stronger phenotypic signs of activation as compared to cells lacking lung-homing receptors, and activation was overall stronger in influenza as compared to COVID-19. Together, our results indicate migration of functionally competent CXCR3+, CXCR6+, and/or CCR5+ NK cells and T cells to the lungs in moderate COVID-19 and influenza patients, identifying potential common targets for future therapeutic interventions in respiratory viral infections. Author summaryThe composition of in particular CXCR3+ and/or CXCR6+ NK cells and T cells is altered in peripheral blood upon infection with SARS-CoV-2 or influenza virus in patients with moderate disease. Lung-homing receptor-expression is biased towards phenotypically activated NK cells and T cells, suggesting a functional role for these cells co-expressing in particular CXCR3 and/or CXCR6 upon homing towards the lung.

immunology↗

bioRxiv2020

Robust T cell immunity in convalescent individuals with asymptomatic or mild COVID-19

ABSTRACTSARS-CoV-2-specific memory T cells will likely prove critical for long-term immune protection against COVID-19. We systematically mapped the functional and phenotypic landscape of SARS-CoV-2-specific T cell responses in a large cohort of unexposed individuals as well as exposed family members and individuals with acute or convalescent COVID-19. Acute phase SARS-CoV-2-specific T cells displayed a highly activated cytotoxic phenotype that correlated with various clinical markers of disease severity, whereas convalescent phase SARS-CoV-2-specific T cells were polyfunctional and displayed a stem-like memory phenotype. Importantly, SARS-CoV-2-specific T cells were detectable in antibody-seronegative family members and individuals with a history of asymptomatic or mild COVID-19. Our collective dataset shows that SARS-CoV-2 elicits robust memory T cell responses akin to those observed in the context of successful vaccines, suggesting that natural exposure or infection may prevent recurrent episodes of severe COVID-19 also in seronegative individuals.Competing Interest StatementThe authors have declared no competing interest.View Full Text

immunology↗

bioRxiv2020

Expansion of SARS-CoV-2-specific Antibody-secreting Cells and Generation of Neutralizing Antibodies in Hospitalized COVID-19 Patients

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in late 2019 and has since become a global pandemic. Pathogen-specific antibodies are typically a major predictor of protective immunity, yet B cell and antibody responses during COVID-19 are not fully understood. Here, we analyzed antibody-secreting cell (ASC) and antibody responses in twenty hospitalized COVID-19 patients. The patients exhibited typical symptoms of COVID-19, and presented with reduced lymphocyte numbers and increased T cell and B cell activation. Importantly, we detected an expansion of SARS-CoV-2 nucleocapsid protein-specific ASCs in all twenty COVID-19 patients using a multicolor FluoroSpot assay. Out of the 20 patients, 16 had developed SARS-CoV-2-neutralizing antibodies by the time of inclusion in the study. SARS-CoV-2-specific IgA, IgG and IgM antibody levels positively correlated with SARS-CoV-2-neutralizing antibody titers, suggesting that SARS-CoV-2-specific antibody levels may reflect the titers of neutralizing antibodies in COVID-19 patients during the acute phase of infection. Lastly, we showed that interleukin 6 (IL-6) and C-reactive protein (CRP) concentrations were higher in serum of patients who were hospitalized for longer, supporting the recent observations that IL-6 and CRP could be used to predict COVID-19 severity. Altogether, this study constitutes a detailed description of clinical and immunological parameters in twenty COVID-19 patients, with a focus on B cell and antibody responses, and provides tools to study immune responses to SARS-CoV-2 infection and vaccination.

immunology↗