What is the Difference Between MHC Class I and MHC Class II?
MHC class I molecules present peptides derived from intracellular proteins and are found on almost all nucleated cells. They are essential for the activation of cytotoxic T cells (CD8+ T cells). MHC class II molecules, on the other hand, present extracellularly derived peptides and are primarily expressed on professional APCs. They are crucial for the activation of helper T cells (CD4+ T cells).
