How does a cytotoxic T cell destroy another cell displaying antigens bound to class I MHC proteins?

Verified step by step guidance

1. Understand that cytotoxic T cells recognize infected or abnormal cells by detecting antigens presented on class I MHC (Major Histocompatibility Complex) proteins on the surface of these target cells.
2. Recall that the T cell receptor (TCR) on the cytotoxic T cell specifically binds to the antigen-MHC class I complex, which activates the cytotoxic T cell.
3. Once activated, the cytotoxic T cell releases cytotoxic molecules such as perforin and granzymes toward the target cell.
4. Perforin forms pores in the target cell's membrane, allowing granzymes to enter the cytoplasm of the target cell.
5. Granzymes trigger apoptosis (programmed cell death) in the target cell, leading to its destruction without causing inflammation.

Key Concepts

Cytotoxic T Cell Function

Cytotoxic T cells (CD8+ T cells) are immune cells that identify and kill infected or abnormal cells. They recognize antigens presented by class I MHC molecules on target cells and induce apoptosis to eliminate cells displaying foreign or abnormal peptides.

Class I MHC Antigen Presentation

Class I Major Histocompatibility Complex (MHC) proteins present endogenous peptides, including viral or abnormal proteins, on the surface of almost all nucleated cells. This presentation allows cytotoxic T cells to monitor and detect infected or transformed cells.

Mechanisms of Target Cell Killing

Upon recognition, cytotoxic T cells release perforin and granzymes that create pores and trigger apoptosis in the target cell. They can also engage death receptors like Fas to initiate programmed cell death, effectively destroying the infected or abnormal cell.