Atypical Antibody Dynamics During Human Coronavirus HKU1 Infections

Abstract

Human coronavirus HKU1 (HCoV-HKU1) is one of the four endemic coronaviruses. It has been suggested that there is a difference in incidence, with PCR-confirmed HCoV-NL63 and HCoV-OC43 infections occurring more commonly, whereas HCoV-HKU1 is the least seen. Lower incidence of HCoV-HKU1 infection has also been observed in serological studies. The current study aimed to investigate antibody dynamics during PCR-confirmed HCoV-HKU1 infections using serum collected during infection and 1 month later. We expressed a new HCoV-HKU1 antigen consisting of both the linker and carboxy-terminal domain of the viral nucleocapsid protein and implemented it in ELISA. We also applied a spike-based Luminex assay on serum samples from PCR-confirmed infections by the four endemic HCoVs. At least half of HCoV-HKU1-infected subjects consistently showed no antibody rise via either assay, and some subjects even exhibited substantial antibody decline. Investigation of self-reported symptoms revealed that HCoV-HKU1-infected subjects rated their illness milder than subjects infected by other HCoVs. In conclusion, HCoV-HKU1 infections reported in this study displayed atypical antibody dynamics and milder symptoms when compared to the other endemic HCoVs.

Pre-existing immunity to SARS-CoV-2 before the COVID-19 pandemic era in Cameroon: A comparative analysis according to HIV-status

“…The later could also be justified by a previous contact with other coronaviruses sharing common antigenic profiles ( 4 , 8 ), which could be either HKU1, NL63, OC43 or 229E. Moreover, the circulation of these specific coronaviruses within Central Africa had never been described before the COVID-19 outbreak ( 22 , 23 ).. Assessing the titer and immunogenicity of these specific pre-pandemic SARS-CoV-2 antibodies through broadly neutralizing assays will help confirm this hypothesis and further characterize this cross-immunity to understand its effect on SARS-CoV-2 variants and sub-lineages circulating nowadays ( 24 ). On one hand, we observed a higher sero-positivity SARS-CoV-2 antibodies among males as compared to females, likely driven by the differential level of ACE-2 receptors among men as compared to women ( 8 , 25 ).…”

Human coronavirus HKU1 recognition of the TMPRSS2 host receptor

“…(G) Neutralization of VSV pseudotyped with wildtype isolate N1 HKU1 S (WT) or the N355 glycan knockout (S357A) mutant by serum antibodies elicited by HKU1 infection. Visits 1 and 2 correspond to blood draws at the time of PCR-positive testing and 1-2 months later, respectively 52, 53 . Neutralization values were compared by two-way ANOVA with the Geisser-Greenhouse correction and Tukey’s multiple comparison test; * corresponds to a P value of 0.02, while *** corresponds to a P value of 0.0007.…”

“…To investigate the relationship between antibody specificity and viral inhibition, we assessed neutralizing antibody titers against an HKU1 isolate N1 S VSV using human sera collected after PCR-confirmed HKU1 infection. These serum samples were collected in four European countries between 2007 and 2010 at the time of PCR-positive testing (Visit 1) and 1-2 months later (Visit 2) 52, 53 . Neutralizing antibody titers ranged from half-maximum inhibition dilution of 1/10 to 1/80 for a geometric mean of 1/23 for visit 1 and 1/49 for visit 2 ( Figure 5G and Figure S6 ).…”

“…Dose-response curves for neutralization of VSV pseudotyped with wildtype isolate N1 HKU1 S (WT, red) or the N355 glycan knockout (S357A, blue) mutant by human serum antibodies, shown in red and blue, respectively. Visits 1 and 2 correspond to blood draws at the time of PCR-positive testing and 30 days later, respectively 52, 53 .…”

Efficacy of novel SARS-CoV-2 rapid antigen tests in the era of omicron outbreak

“…Among the identified human coronaviruses (hCoVs), the genus betacoronavirus (β-CoV), which contains four lineages (A, B, C, and D), is of the greatest clinical significance concerning humans. The β-CoVs that have raised concerns worldwide include HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU-1, severe acute respiratory syndrome coronavirus (SARS-CoV), and middle east respiratory syndrome-related coronavirus (MERS-CoV) [4][5][6].…”