Suchergebnisse

Currently, there is a need for reliable tests that allow identification of individuals that have been infected with SARS-CoV-2 even if the infection was asymptomatic. To date, the vast majority of the serological tests for SARS-CoV-2 specific antibodies are based on serum detection of antibodies to either the viral spike glycoprotein (the major target for neutralising antibodies) or the viral nucleocapsid protein that are known to be highly immunogenic in other coronaviruses. Conceivably, exposure of antigens released from infected cells could stimulate antibody responses that might correlate with tissue damage and, hence, they may have some value as a prognostic indicator. We addressed whether other non-structural viral proteins, not incorporated into the infectious viral particle, specifically the viral cysteine-like protease, might also be potent immunogens. Using ELISA tests, coating several SARS-CoV-2 proteins produced in vitro, we describe that COVID-19 patients make high titre IgG, IgM and IgA antibody responses to the Cys-like protease from SARS-CoV-2, also known as 3CLpro or Mpro, and it can be used to identify individuals with positive serology against the coronavirus. Higher antibody titres in these assays associated with more severe disease and no cross-reactive antibodies against prior betacoronavirus were found. Remarkably, IgG antibodies specific for Mpro and other SARS-CoV-2 antigens can also be detected in saliva. In conclusion, Mpro is a potent antigen in infected patients that can be used in serological tests and its detection in saliva could be the basis for a rapid, non-invasive test for COVID-19 seropositivity. ; This work was supported by the Spanish National Research Council (CSIC, project number 202020E079) and grants from Madrid Regional Government IMMUNOTHERCAN [S2017/BMD-3733-2 (MVG)]; the Spanish Ministry of Science and Innovation [(MCIU/AEI/FEDER, EU): RTI2018-093569-B-I00 (MVG), SAF2017-82940-R (JMRF), SAF2017-83265-R (HTR); SAF2017-82886-R (FSM)]; RETICS Program of ISCIII [RD16/0012/0006; RIER (JMRF); RD16/0011/0012, PI18/0371 (IGA), PI19/00549 (AA)]. The study was also funded by La Caixa Banking Foundation (HR17-00016 to FSM) and Fondo Supera COVID (CRUE-Banco de Santander) to FSM ; No

Abstract Background Epstein-Barr virus (EBV) infection is a well characterized etiopathogenic factor for a variety of immune-related conditions, including lymphomas, lymphoproliferative disorders and autoimmune diseases. EBV-mediated transformation of resting B cells to proliferating lymphoblastoid cells occurs in early stages of infection and is an excellent model for investigating the mechanisms associated with acquisition of unlimited growth. Results We investigated the effects of experimental EBV infection of B cells on DNA methylation profiles by using high-throughput analysis. Remarkably, we observed hypomethylation of around 250 genes, but no hypermethylation. Hypomethylation did not occur at repetitive sequences, consistent with the absence of genomic instability in lymphoproliferative cells. Changes in methylation only occurred after cell divisions started, without the participation of the active demethylation machinery, and were concomitant with acquisition by B cells of the ability to proliferate. Gene Ontology analysis, expression profiling, and high-throughput analysis of the presence of transcription factor binding motifs and occupancy revealed that most genes undergoing hypomethylation are active and display the presence of NF-κB p65 and other B cell-specific transcription factors. Promoter hypomethylation was associated with upregulation of genes relevant for the phenotype of proliferating lymphoblasts. Interestingly, pharmacologically induced demethylation increased the efficiency of transformation of resting B cells to lymphoblastoid cells, consistent with productive cooperation between hypomethylation and lymphocyte proliferation. Conclusions Our data provide novel clues on the role of the B cell transcription program leading to DNA methylation changes, which we find to be key to the EBV-associated conversion of resting B cells to proliferating lymphoblasts. ; This work was supported by grants PI081346 (FIS) and SAF2011-29635 from the Spanish Ministry of Science and Innovation (MICINN) and grant 2009SGR184 from AGAUR (Catalan Government). AI was supported by fellowship from AGAUR, Government of Catalonia, Spain. MP is supported by Ramon y Cajal Programme. ; Peer Reviewed

The rapid development of mRNA-based vaccines against the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) led to the design of accelerated vaccination schedules that have been extremely effective in naive individuals.While a two-dose immunization regimen with the BNT162b2 vaccine has been demonstrated to provide a 95% efficacy in naive individuals, the effects of the second vaccine dose in individuals who have previously recovered from natural SARS-CoV-2 infection has not been investigated in detail. In this study, we characterize SARS-CoV-2 spike-specific humoral and cellular immunity in naive and previously infected individuals during and after two doses of BNT162b2 vaccination. Our results demonstrate that, while the second dose increases both the humoral and cellular immunity in naive individuals, COVID-19 recovered individuals reach their peak of immunity after the first dose. These results suggests that a second dose, according to the current standard regimen of vaccination, may be not necessary in individuals previously infected with SARS-CoV-2. ; Research reported in this publication was supported in part by the National Cancer Institute of the NIH (5R01HD102614-02; R01CA249204 and R01CA248984) and an ISMMS seed fund to E.G. The authors gratefully acknowledge use of the services and facilities of the Tisch Cancer Institute supported by a NCI Cancer Center Support Grant (P30 CA196521). M.S. was supported by a NCI training grant (T32CA078207). This work was supported by an ISMMS seed fund to J.O.; Instituto de Salud Carlos III (COV20-00668) to R.C.R.; the Instituto de Salud Carlos III, Spanish Ministry of Science and Innovation (COVID-19 research call COV20/00181) co-financed by the European Development Regional Fund "A way to achieve Europe" to E.P.; the Instituto de Salud Carlos III, Spain (COV20/00170); the Government of Cantabria, Spain (2020UIC22-PUB-0019) to M.L.H.; the Instituto de Salud Carlos III (PI16CIII/00012) to P.P.; the Fondo Social Europeo e Iniciativa de Empleo Juvenil YEI (Grant PEJ2018-004557-A) to M.P.E.; and by REDInREN 016/009/009 ISCIII. This project has received funding from the European Union Horizon 2020 research and innovation programs VACCELERATE and INsTRuCT under grant agreements 101037867 and 860003. ; Peer reviewed