Part of the heterogeneity seen in COVID-19 disease has been suggested to be due to pre-existing cross-reactive memory T cells remaining from previous infections with common cold human corona virus (hCoV). A recent paper from the Sette lab at La Jolla Institute for Immunology confirms that notion. The authors first mapped down 142 SARS-CoV-2 CD4 T cell epitopes. Then they were able to show, in pre-COVID-19 blood samples, pre-existing CD4 memory T cells specific for hCoVs but cross-reactive to several of the SARS-CoV-2 epitopes.
The findings are important as they not only explain differences in clinical outcomes, but also may have an impact on models of herd immunity and vaccine development.
The epitope mapping and subsequent hCoV-cross-reactivity studies were performed using our FluoroSpot Plus: IFN-γ/IL-5 and analyzed on the Mabtech IRIS.