On the other hand, we could show that the SARS-CoV-2 HLA class I-restricted EC could also be recognized by CD4+ T cells, which is an often described phenomenon, especially in viral diseases (28, 29), as both HLA class I and class II molecules could bind to primary and secondary peptide anchor motifs covering the central 9 - 10 amino acids. The gene discussed is CD4; the disease is viral infectious disease.