What happens when granulysin enters a cell through channels created by perforin?

What happens when granulysin enters a cell through channels created by perforin?

• A. It binds to receptors to activate T cells
• B. It induces apoptosis
• C. It causes cellular lysis
• D. It inhibits antigen presentation

Answer: (C)

When granulysin enters a cell through channels created by perforin, it primarily induces apoptosis, which is a programmed form of cell death essential for maintaining homeostasis and eliminating infected or dysfunctional cells. Apoptosis is a highly regulated process that ensures the cell's contents are contained, preventing inflammation and damage to surrounding tissues.

Perforin is responsible for forming pores in the target cell membrane, allowing granule proteins such as granulysin to enter. Once inside, granulysin can interact with various cellular components to trigger the apoptotic pathway. This action is part of the immune response to eliminate cells infected by pathogens or to control excessive cell growth, reflecting a significant defense mechanism used by cytotoxic T lymphocytes and natural killer cells.

The options suggesting roles such as activating T cells, causing cellular lysis, or inhibiting antigen presentation do not accurately reflect the specific action of granulysin. Granulysin's primary function upon entering a target cell is mediation of apoptosis rather than direct lysis or interference with T cell activation or antigen presentation processes.