What is one function of perforin in the immune response?

• A. To enhance B cell activity
• B. To lyse infected cells
• C. To stimulate cytokine production
• D. To promote inflammation

Answer: (B)

Perforin plays a crucial role in the immune response, particularly in the elimination of infected cells. This protein is produced by cytotoxic T cells and natural killer (NK) cells. When these immune cells identify a cell that is infected with a virus or has turned cancerous, they release perforin in conjunction with granzymes. Perforin creates pores in the target cell's membrane, leading to cell lysis, which ultimately results in the destruction of the infected or abnormal cell.

This mechanism is vital for the immune system's ability to control infections and eliminate malignant cells. By facilitating the direct lysis of cells that harbor pathogens, perforin ensures that the spread of infections is curtailed and that immune surveillance is maintained.