NSP12 is a large SARS-CoV-2 protein with 932 amino acid residues catalysing replication and transcription of the viral genome [45]. regressionCoefficientStd. errorvalueHospitalization duration??Anti-S/N IgM0.3050.1090.0075??Tumour disease5.9801.300?P?P?Mouse monoclonal to pan-Cytokeratin absolute variant count per gene and patient, most variants were located within ORF1ab representing the largest SARS-CoV-2 ORF. Nevertheless, ORF1ab showed a significantly lower variation rate normalized around the gene length compared to the other genes, while the N gene was the only gene with a significantly higher normalized variation rate. Overall, RNA viruses are known to accumulate variants rapidly during their replication cycle because RNA copying enzymes are prone to error [15, 16]. A high variation rate of the N gene was reported elsewhere [17, 18]. ORF10 was the only gene without variants in our study which was also exhibited elsewhere [18]. Furthermore, our study corroborated published data around the S gene stability [19]. We observed four variants present in all samples (ORF1ab F924F, ORF1ab P4715L, S D614G and 5?UTR 241C?>?T), representing signature variants of the most dominant SARS-CoV-2 type VI strain [20]. In particular, the D614G exchange in the S protein has been SKA-31 extensively studied and is postulated to provide a selection advantage through increased viral infectivity [21C23]. All samples were assigned to the root lineage B based on Rambauts nomenclature [24]. The highest level lineage was B.1, encompassing the major Italian outbreak in early 2020 and then spreading SKA-31 across Europe [24]. The other identified lineages were sub-lineages of B.1, which match the geographical origin of the samples. Remarkably, the earliest description dates of the lineages in the Pango strain database coincided with our sample collection date (2020C04-07 to 2020C05-07). At the time of writing this manuscript, the lineages B.1.322, B.1.353 and B.1.5 have already been SKA-31 reassigned as more and more SARS-CoV-2 whole genomes have been sequenced over time and lineage formation and extinction continue to progress [24]. Given the high genetic variability of SARS-CoV-2, we sought to investigate the emergence of the humoral immune response by determining specific IgM and IgG against the most immunogenic S and N proteins in average 83?days after PCR testing [25, 26]. As expected, all patients revealed detectable anti-S/N and anti-N IgG while only one patient out of the examined 49 did not show anti-S1 IgG. The higher anti-S/N IgG prevalence in contrast to IgM probably indicates the effect of an immunological memory likely induced by previous infections with endemic coronaviruses, as primary immune responses would induce stronger anti-SARS-CoV-2 IgM responses. For all those antibodies tested, there was no correlation between time from SARS-CoV-2 PCR testing and antibody levels within the examined period of 83?days on average after SARS-CoV-2 PCR testing. However, it cannot be ruled out that anti-S/N IgM levels, in particular, may have decreased to negative values in the period leading up to blood collection for antibody determination. Rank correlation and multiple regression analyses using genetic SARS-CoV-2 variants and patient characteristics as impartial variables for the prediction of anti-SARS-CoV-2 antibody levels revealed an association of older age (>?65?years) and overweight (BMI?>?25) with higher anti-S/N and anti-S1 IgG levels. In contrast, higher anti-N IgG levels were only associated with older age. The average age of enrolled patients was 52.2?years which is in agreement with the reported age of around 50?years for COVID-19 patients [1, 27]. A systematic review and.