LIFE SCIENCE

Detailed explanation-1: -Each MHC molecule on the cell surface displays a small peptide (a molecular fraction of a protein) called an epitope. The presented self-antigens prevent an organism’s immune system from targeting its own cells.

Detailed explanation-2: -In a classical view, MHC-I molecules present peptides from intracellular source proteins, whereas MHC-II molecules present antigenic peptides from exogenous and membrane proteins. Nevertheless, substantial crosstalk between these two pathways has been observed.

Detailed explanation-3: -The major histocompatibility (MHC) class I antigen presentation pathway plays an important role in alerting the immune system to virally infected cells. MHC class I molecules are expressed on the cell surface of all nucleated cells and present peptide fragments derived from intracellular proteins.