Loading...
2 results
Search Results
Now showing 1 - 2 of 2
- Seroprevalence of anti‐SARS‐CoV‐2 antibodies in COVID‐19 patients and healthy volunteers up to 6 months post disease onsetPublication . Figueiredo-Campos, Patricia; Blankenhaus, Birte; Mota, Catarina; Gomes, Andreia; Serrano, Marta; Ariotti, Silvia; Costa, Catarina; Nunes-Cabaço, Helena; Mendes, António M.; Gaspar, Pedro; Pereira‐Santos, M. Conceição; Rodrigues, Fabiana; Condeço, Jorge; Escoval, M. Antonia; Santos, Matilde; Ramirez, Mário; Cristino, José Melo; Simas, J Pedro; Vasconcelos, Eugenia; Afonso, Ângela; Veldhoen, MarcSARS-CoV-2 has emerged as a human pathogen, causing clinical signs, from fever to pneumonia-COVID-19-but may remain mild or asymptomatic. To understand the continuing spread of the virus, to detect those who are and were infected, and to follow the immune response longitudinally, reliable and robust assays for SARS-CoV-2 detection and immunological monitoring are needed. We quantified IgM, IgG, and IgA antibodies recognizing the SARS-CoV-2 receptor-binding domain (RBD) or the Spike (S) protein over a period of 6 months following COVID-19 onset. We report the detailed setup to monitor the humoral immune response from over 300 COVID-19 hospital patients and healthcare workers, 2500 University staff, and 198 post-COVID-19 volunteers. Anti-SARS-CoV-2 antibody responses follow a classic pattern with a rapid increase within the first three weeks after symptoms. Although titres reduce subsequently, the ability to detect anti-SARS-CoV-2 IgG antibodies remained robust with confirmed neutralization activity for up to 6 months in a large proportion of previously virus-positive screened subjects. Our work provides detailed information for the assays used, facilitating further and longitudinal analysis of protective immunity to SARS-CoV-2. Importantly, it highlights a continued level of circulating neutralising antibodies in most people with confirmed SARS-CoV-2.
- Immune-microbe crosstalk : modulation of adaptive immune system by the microbiota and SARS-CoV2Publication . Figueiredo-Campos, Patricia; Veldhoen, MarcAdaptive immune responses are supported by lymphocytes that are broadly divided into B and T cells, which provide antibody and cell-mediated immune responses, respectively. Adaptive immunity is characterized by a specific pathogen recognition, generation of memory, and regulation of homeostasis. Lymphocytes develop and are activated in the lymphoid organs and can also re-circulate within the tissues. Intestinal Intraepithelial lymphocytes (IELs) occupy the top layers of epithelial barriers and are broadly composed of natural IELs (CD8ααTCRγδ) and induced IELs (CD8αβTCRαβ and CD4TCRαβ). IELs are kept in a heightened but controlled state of activation, have reciprocal interactions with the intestinal epithelial cells (IECs) and microbiota. There is evidence supporting that IELs contribute to the pathogenesis of gut disorders such as celiac disease and inflammatory bowel disease (IBD). Yet, the stimuli that control IELs activity and the molecular pathways involved remain unclear. In the context of a parasite infection, caused by Eimeria vermiformis that infects mouse IECs, induced IELs but not natural IELs are strongly activated. Interestingly, upon treatment with broad-spectrum antibiotics, followed by E.vermiformis infection, natural IELs proliferation is boosted. This proliferation boost is traced to Grampositive bacteria, the major producers of short-chain fatty acids (SCFA) and lactate. The hyperproliferative phenotype was also observed in the context of antibiotics and Dextran Sulphate Sodium (DSS) treatment. However, here just natural IELs got activated and induced IELs were not affected by the treatment. Importantly, the IEL proliferation boost is reversed by faecal microbiota transplantation (FMT) under antibiotics treatment and infection compared with no FMT. IELs do not express SCFA receptors but glucagon-like peptide-1 receptor (GLP-1R) is highly expressed by them. Fatty acid and lactate receptors are expressed by intestinal enteroendocrine L cells that produce GLP-1. Interestingly, we found GLP-1 mRNA and serum levels increased upon antibiotics treatment and DSS or E.vermiformis infection. Moreover, administration of Ex-9, a GLP-1 antagonist, reduced natural IELs proliferation. A diverse microbiota composition is important to sustain IELs and maintain their semi-activated state without effector function. Upon bacterial dysbiosis, especially reduced Gram-positives, natural IELs proliferation is released, and GLP-1 levels are increased. Currently, we characterise the microbiota complexity via 16S rRNA sequencing to understand the community that is responsible for keeping the natural IELs at the quiet state of activation. In the absence of this community, natural IELs proliferation is released, which could lead to gut inflammation, such as seen in IBD. Therefore, by manipulating the microbiota composition, the importance of specific bacteria and/or bacterial products that influence natural IELs activation and function will be addressed. This way, it will be possible to control the proliferation and activation of these cells to restore gut homeostasis. On December 2019 a novel virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), was first identified from an outbreak in Wuhan, China, being responsible for the COVID-19 pandemic. In Portugal, the first case was reported in March 2020. In April 2020, we started working to understand the spreading of the virus, to identify those who are and were infected, and to follow the immune response longitudinally. We created a reliable and robust assay for SARS-CoV-2 detection and immunological monitoring. We designed an Enzyme linked immunosorbent assay (ELISA) assay to quantify IgM, IgG, and IgA antibodies against SARS-CoV-2 receptor-binding domain (RBD) or the Spike (S) protein. We described the meticulous setup to monitor the humoral immune response of over 300 COVID-19 hospital patients and healthcare workers, 2500 University staff, and 198 post-COVID-19 volunteers. SARS-CoV-2 infection induced a classic pattern of antibody responses with a rapid increase within the first three weeks after symptoms. Anti-SARS-CoV-2 IgG antibodies reduced in titres, although remaining robust with confirmed neutralization activity for up to 6 months in a large proportion of previously virus-positive screened individuals. Our work provides detailed information for the assays used, facilitating longitudinal analysis of protective immunity to SARS-CoV-2. Importantly, it highlights a continued level of circulating neutralising antibodies in most people with confirmed SARS-CoV-2.