analysed data and prepared the figures

analysed data and prepared the figures. findings, although negative, contribute to Erlotinib HCl the current knowledge on potential Mouse monoclonal to HDAC4 cross-immunity against SARS-CoV-2 from previous immunizations. adjusted Odds Ratio, Confidence Interval, Research category for logistic regression, Severe Acute Respiratory Syndrome Coronavirus 2, Standard Deviation, Tick-Borne Encephalitis Computer virus. No cross-neutralization of TBEV antibodies against SARS-CoV-2 We analysed 26 baseline (T1, March/April 2020) and follow-up (T2, August/September 2020) samples divided into three groups defined above. Group characteristics are summarized in Table ?Table22. Table 2 Characteristics of 26 healthcare workers and their TBEV/SARS-CoV-2 serostatus at time points T1 and T2. Severe Acute Respiratory Syndrome Coronavirus-2, Tick-Borne Encephalitis Computer virus. As expected, all four individuals in group 1 experienced neutralizing antibodies against SARS-CoV-2 in their follow-up (T2), but not in their baseline (T1) sample (Fig.?1a, blue). However, none of the sera from group 2 exhibited any cross-neutralization against SARS-CoV-2 (Fig.?1a, black). Thus, anti-TBEV-antibodies did not have any direct neutralizing effect on SARS-CoV-2 in these samples. Additionally, all four individuals (100%) from group 1 and 16/17 individuals (94%) from group 2 experienced neutralizing antibodies against TBEV in both baseline and follow-up samples, except for one individual from group 2 who tested unfavorable at T1 but positive at T2. Within the control (group 3), four individuals tested unfavorable for neutralizing antibodies against TBEV as expected, whereas one tested positive Erlotinib HCl at both T1 and T2 (Fig.?1b, red). As individuals were assigned to groups based on their vaccination history, this person is likely to have acquired anti-TBEV antibodies naturally. Overall, neutralizing TBEV antibody titers were significantly higher in the follow-up samples (T2) than in the baseline samples (T1) (P? ?0.0001). However, Erlotinib HCl this pattern was observed in both groups 1 and 2, therefore these results do not allow for any conclusions about a brought on TBEV antibody response due to a recent SARS-CoV-2 contamination. Furthermore, an increase in TBEV neutralizing antibody titer was only observed in 50% of positive samples (11/22). Open in a separate window Physique 1 Serum neutralization test (SNT) revealed no cross-protection between SARS-CoV-2 and TBEV. (a) Neutralization against SARS-CoV-2 was only observed in convalescent patients (4/4, blue) and no cross-reactivity was observed in individuals vaccinated against Erlotinib HCl TBEV (black). (b) Neutralization of TBEV was observed in almost all individuals vaccinated against TBEV at T1 (16/17, black) and increased significantly between sampling points (T2, 17/17); ***p?=?0.001. Dashed collection: Limit of detection, 1:16 serum dilution. Non-neutralizing samples are assigned the value 10. March/April 2020, August/September 2020, blue: SARS-CoV-2 convalescents, black: TBEV vaccinees, reddish: unfavorable control group. Significant increase in anti-TBEV IgG titer in follow up samples The qualitative results of anti-TBEV-IgG ELISA are in agreement with the observed serum neutralization test (SNT) results. As observed for neutralizing TBEV antibody titers, anti-TBEV IgG titers determined by ELISA were significantly higher in the follow-up samples (T2, higher titer in 16 of 22 samples) than in the baseline samples (T1), (P? ?0.0001), again irrespective of SARS-CoV-2 serostatus (Fig.?2a). For IgM, we observed a pattern towards decreasing antibody titers from T1 to T2 for all those but two samples. For these two samples (one each within groups 1 and 2), IgM seroconversion was observed, however at low titers (Fig.?2b). Open in a separate window Physique 2 Significant increase was observed in anti-TBEV IgG antibodies in follow up samples(a) Anti-TBEV IgG antibodies were significantly increased in follow up samples compared to baseline (T2, 16/22); **** p? ?0.0001. (b) IgM seroconversion was observed in one sample with an equivocal increase in another. Dashed lines: Limit of negativity; IgG: 100U/ml, IgM: 10U/ml. March/April 2020, August/September 2020. Group 1, blue: SARS-CoV-2 convalescents, group 2, black: TBEV vaccinees, group 3, reddish: unfavorable control group. Conversation In the current study, we found an association between previous TBEV vaccination and decreased rates of SARS-CoV-2 seroconversion within a prospective cohort of Swiss HCWs. The observed association could not be explained by any cross-neutralizing effect of anti-TBEV antibodies on SARS-CoV-2. Unexpectedly, anti-TBEV antibody titers increased overall between baseline Erlotinib HCl and follow-up samples, irrespective of SARS-CoV-2 seroconversion, albeit not in all samples. The hypothesis that pre-existing TBEV antibodies.