ABSTRACT
In a study of two Hospitals in Saxony (Chemnitz and Leipzig), we analyzed the antibody development towards SARS-CoV-2 and against a variety of endemic coronaviruses. Here we analyzed 760 sera from a Saxonian cohort for antibody reactivity against: Common cold coronaviruses, HCoV-229E, HCoV-HKU 1, HCoV-NL63 and HCoV-OC43, MERS-CoV and SARS-CoV. For the SARS CoV-2 immune response we tested the following antigens: Spike, S1, S2, RBD and nucleocapsid. These 11 antigen determinants were tested in a commercial multiplex Luminex based assay. We tested sera from 544 individuals (347 females and 197 males;498 SARS-CoV-2 PCR positive and 262 SARS-CoV-2 PCR negative) between May 2020 and March 2022. We observed up to 10% reactivity against the MERS virus in both the PCR positive and negative group. Against the common cold corona viruses 80%-90 % of the individuals in both groups show detectable antibodies. Regarding the antibody response against SARS-CoV a significant difference was observe. Only 19% of COVID-19 infected individuals show antibodies against the virus, while 81% of the PCR-positive individuals produced antibodies. The presence of antibodies against the SARS-CoV-2 is positively correlated with those against SARS-CoV (p = 0.001). No changes in endemic antibody responses were see in the two groups. The antibody status after first immunization event (infection/ vaccination) shows differences in nucleocapsiddirected antibody production, found in the natural infection group (about 60%). In the vaccination group, more individuals (up to 95%) show an immune response against Spike, S1 and RBD compare with natural infection. In summary, the examined cohort shows a general immunization up to 90% against most endemic corona viruses. Correlation analyses show cross-reactivity between SARS-CoV-2 and SARS-CoV. Longitudinal antibody analyses are under way, as also correlations of humoral response with immunogenetic factors.