Coronavirus spike-receptor interactions

The history of coronaviruses started in the 1930s when avian infectious bronchitis virus (IBV) was first described as the causative agent of infectious bronchitis in poultry flocks (1-2). In the mid-1960s, two human coronaviruses, 229E (HCoV- 229E) and OC-43 (HCoV-OC43), were identified as pathogens for common-colds in humans (3-5). Early studies on human coronaviruses were primarily focused on the epidemiology of these viruses using serological techniques. Coronaviruses were demonstrated to contribute to as much as 35% of respiratory infections in humans during epidemics (6). In 1975, the Coronaviridae family with one genus, coronavirus, was officially established, referring to the crown-like appearance of spikes on the surface of these viruses (7).