MICROANATOMY

Detailed explanation-1: -T cells can detect the presence of an intracellular pathogen because infected cells display on their surface peptide fragments derived from the pathogen’s proteins. These foreign peptides are delivered to the cell surface by specialized host-cell glycoproteins.

Detailed explanation-2: -So what do T cells recognize? T cells have dual specificity, so they recognize both self-major histocompatibility complex molecules (MHC I or MHC II) and peptide antigens displayed by those MHC molecules.

Detailed explanation-3: -Armed effector cytotoxic CD8 T cells are essential in host defense against pathogens that live in the cytosol, the commonest of which are viruses. These cytotoxic T cells can kill any cell harboring such pathogens by recognizing foreign peptides that are transported to the cell surface bound to MHC class I molecules.