Biology subjects

Sällberg, M.

Publications and source records attributed to Sällberg, M..

3 recordsLinked to original sources

bioRxiv2026

Dual-Antigen CCHFV Vaccine Induces Neutralizing Immunity and Protection Against Lethal Challenge

Crimean-Congo hemorrhagic fever virus (CCHFV) is a WHO-priority pathogen with high mortality and wide global distribution. A major challenge in CCHFV vaccine development is identifying antigens that induce functional cellular and humoral immunity. We previously showed that the CCHF nucleoprotein (NP) elicits protective responses in mice and non-human primates but does not induce neutralizing antibodies. We therefore systematically screened six chimeric DNA vaccines expressing different CCHF glycoproteins combined with NP. A construct comprising the ectodomain of the glycoprotein Gc and NP elicited robust antibody and T-cell responses to both antigens. The Gc-NP gene was subsequently developed as a lipid nanoparticle-formulated mRNA vaccine using a scalable manufacturing pipeline. Gc-NP mRNA-LNP induced robust antigen-specific humoral and cellular responses comparable to those elicited by the corresponding DNA vaccine, despite the substantially lower dose. Both vaccine approaches generated Gc-directed neutralizing antibody responses against CCHFV pseudovirus and protected mice against homologous Hoti and heterologous IbAr10200 strain challenge. These findings demonstrate that systematic antigen screening combined with genetic vaccine platforms can identify a potent multi-antigen CCHF vaccine candidate.

immunology↗

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↗

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↗