Diverse Humoral Immune Responses in Younger and Older Adult COVID-19 Patients

Abstract

We sought to discover links between antibody responses to SARS-CoV-2 and patient clinical variables, cytokine profiles and antibodies to endemic coronaviruses. Serum from patients of varying ages and clinical severity were collected and used to probe a novel multi-coronavirus protein microarray containing SARS-CoV-2 proteins and overlapping protein fragments of varying length as well as SARS-CoV, MERS-CoV, HCoV-OC43 and HCoV-NL63 proteins. IgG, IgA and IgM antibody responses to specific epitopes within the spike (S), nucleocapsid (N) and membrane proteins (M) were higher in older adult patients. Moreover, the older age group displayed more consistent correlations of antibody reactivity with systemic cytokine and chemokine responses when compared to the younger adult group. A subset of patients, however, had little or no response to SARS-CoV-2 antigens and disproportionately severe clinical outcomes. Further characterization of these serosilent individuals with cytokine analysis revealed significant differences in IL-10, IL-15, IP-10, EGF and sCD40L levels when compared to seroreactive patients in the cohort.