GENERAL HISTOLOGY

Detailed explanation-1: -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-2: -Usually, in the thymus T cells that recognize self MHC + self peptides are deleted and those with the potential to recognize self MHC + foreign peptides are selected to mature. However there are exceptions to these rules.

Detailed explanation-3: -The nature of the antigen recognized by T cells became clear with the realization that the peptides that stimulate T cells are recognized only when bound to an MHC molecule. These cell-surface glycoproteins are encoded by genes within the major histocompatibility complex (MHC).

Detailed explanation-4: -When the perfectly shaped virus antigen on an infected cell fits into the Killer T-cell receptor, the T-cell releases perforin and cytotoxins. Perforin first makes a pore, or hole, in the membrane of the infected cell. Cytotoxins go directly inside the cell through this pore, destroying it and any viruses inside.