Effective presence of antibodies against common human coronaviruses in immunoglobulin medicinal products.

Background: Immunoglobulin products (for intravenous, intramuscular and subcutaneous administration) prepared from geographically diverse plasma pools were tested for activity against common human coronaviruses (HCoVs). Products from plasma obtained from Germany, Czech Republic, Slovak Republic, USA and Spain were tested for antibodies to common HCoVs: 229E, OC43, NL63 and HKU1. As these products are manufactured from pooled plasma from thousands of donors, the antibodies therein are representative of HCoV exposure in the population at large.

Methods: Immunoglobulin products were tested for antibodies to four common HCoVs by enzyme-linked immunosorbent assays (ELISAs). Neutralization assays were conducted using HCoV-229E cultured on to MRC5 cells.

Results: ELISAs showed that when expressed as specific activity (anti-HCoV activity/mg immunoglobulin), similar activity against the four common HCoVs was seen across the immunoglobulin products regardless of concentration or geographic origin. Highest anti-HCoV activity was seen against HCoV-229E, followed by HCoV-OC43, HCoV-NL63 and HCoV-HKU1. The neutralization assays showed similar potency for two immunoglobulin products prepared by different processes.

Conclusions: To the authors' knowledge, this is the first demonstration of antibodies to common HCoVs in immunoglobulin products. These results may explain the cross-reactivity seen with pre-pandemic immunoglobulin products and severe acute respiratory syndrome coronavirus-2, and contribute to differences in severity of illness between patients.