IMMUNOLOGY

Detailed explanation-1: -Cytotoxic CD8+ T cells provide protection by recognizing viral peptides loaded onto MHC-I molecules on the cell surface of infected cells, which triggers the delivery of cytotoxic molecules and releasing antiviral cytokines to kill the infected cells (4, 5).

Detailed explanation-2: -The function of MHC molecules is to bind peptide fragments derived from pathogens and display them on the cell surface for recognition by the appropriate T cells.

Detailed explanation-3: -Classical MHC class I molecules are ubiquitously expressed on all mammalian cells including cells of epithelial origin while MHC class II molecules are selectively expressed on antigen-presenting cells (APC) including dendritic cells (DC), macrophages, and B cells.