Abstract
Virus SARS-CoV-2 means the complex challenge for the immune system that induces a complex antiviral defense. This comprises epithelial interfaces and both innate and specific immunity.
T cells can response specifically to antigenic peptides derived from all immunodominant components of SARS-CoV-2. B cells are forming specific antibodies reacting especially with immunogenic determinants of S glycoprotein and N nucleocapsid protein of SARS-CoV-2.
The natural exposure to either infection or active immunisation with SARS-CoV-2 are inducing immune memory in T and B cells and are enhancing the protective potential of innate immunity. The presence of specific antibodies reacting with S and N antigens of SARS-CoV-2 which are routinely determined can testify the previous exposure to SARS-CoV-2 only.