RESUMEN
Different serological assays were rapidly generated to study humoral responses against the SARS-CoV-2 Spike glycoprotein. Due to the intrinsic difficulty of working with SARS-CoV-2 authentic virus, most serological assays use recombinant forms of the Spike glycoprotein or its receptor binding domain (RBD). Cell-based assays expressing different forms of the Spike, as well as pseudoviral assays, are also widely used. To evaluate whether these assays recapitulate findings generated when the Spike is expressed in its physiological context (at the surface of the infected primary cells), we developed an intracellular staining against the SARS-CoV-2 nucleocapsid (N) to distinguish infected from uninfected cells. Human airway epithelial cells (pAECs) were infected with authentic SARS-CoV-2 D614G or Alpha variants. We observed robust cell-surface expression of the SARS-CoV-2 Spike at the surface of the infected pAECs using the conformational-independent anti-S2 CV3-25 antibody. The infected cells were also readily recognized by plasma from convalescent and vaccinated individuals and correlated with several serological assays. This suggests that the antigenicity of the Spike present at the surface of the infected primary cells is maintained in serological assays involving expression of the native full-length Spike.
Asunto(s)
Membrana Celular/metabolismo , Células Epiteliales/metabolismo , Glicoproteína de la Espiga del Coronavirus/metabolismo , Anticuerpos Antivirales/inmunología , Citotoxicidad Celular Dependiente de Anticuerpos , Bronquiolos/citología , Células Cultivadas , Proteínas de la Nucleocápside de Coronavirus/metabolismo , Células Epiteliales/virología , Células HEK293 , Humanos , Pruebas de Neutralización , Fosfoproteínas/metabolismo , SARS-CoV-2/inmunología , SARS-CoV-2/metabolismo , Glicoproteína de la Espiga del Coronavirus/genética , Glicoproteína de la Espiga del Coronavirus/inmunologíaAsunto(s)
Antiinflamatorios/farmacología , Azitromicina/farmacología , Infecciones por Coronavirus/tratamiento farmacológico , Interleucina-1beta/metabolismo , Proteínas de la Membrana/metabolismo , Mucosa Nasal/efectos de los fármacos , Neumonía Viral/tratamiento farmacológico , Serina Endopeptidasas/metabolismo , Serina Proteasas/metabolismo , Betacoronavirus/patogenicidad , COVID-19 , Células Cultivadas , Enfermedad Crónica , Infecciones por Coronavirus/inmunología , Infecciones por Coronavirus/metabolismo , Infecciones por Coronavirus/virología , Regulación hacia Abajo , Interacciones Huésped-Patógeno , Humanos , Interleucina-1beta/genética , Masculino , Proteínas de la Membrana/genética , Mucosa Nasal/inmunología , Mucosa Nasal/metabolismo , Pandemias , Proyectos Piloto , Neumonía Viral/inmunología , Neumonía Viral/metabolismo , Neumonía Viral/virología , Rinitis/tratamiento farmacológico , Rinitis/inmunología , Rinitis/metabolismo , SARS-CoV-2 , Serina Endopeptidasas/genética , Serina Proteasas/genética , Transducción de Señal , Sinusitis/tratamiento farmacológico , Sinusitis/inmunología , Sinusitis/metabolismo , Tratamiento Farmacológico de COVID-19RESUMEN
The seasonal nature of outbreaks of respiratory viral infections with increased transmission during low temperatures has been well established. Accordingly, temperature has been suggested to play a role on the viability and transmissibility of SARS-CoV-2, the virus responsible for the COVID-19 pandemic. The receptor-binding domain (RBD) of the Spike glycoprotein is known to bind to its host receptor angiotensin-converting enzyme 2 (ACE2) to initiate viral fusion. Using biochemical, biophysical, and functional assays to dissect the effect of temperature on the receptor-Spike interaction, we observed a significant and stepwise increase in RBD-ACE2 affinity at low temperatures, resulting in slower dissociation kinetics. This translated into enhanced interaction of the full Spike glycoprotein with the ACE2 receptor and higher viral attachment at low temperatures. Interestingly, the RBD N501Y mutation, present in emerging variants of concern (VOCs) that are fueling the pandemic worldwide (including the B.1.1.7 (α) lineage), bypassed this requirement. This data suggests that the acquisition of N501Y reflects an adaptation to warmer climates, a hypothesis that remains to be tested.