Question 16

Perforins create pores in the cell membrane of their target cells to destroy the cell.

Perforins are immune system molecules that facilitate the destruction of target cells by forming pores in their cell membranes. This action allows for the entry of granzymes, leading to apoptosis or cell death.

A) Lymphotoxins

Lymphotoxins are a type of cytokine produced by T cells that can induce cell death, but they do so through different mechanisms, primarily by triggering apoptosis from within rather than forming pores in the cell membrane. Therefore, they do not directly create pores to destroy target cells.

B) Perforins

Perforins are specifically designed to create pores in the membranes of target cells. This is a critical function in the immune response, particularly by cytotoxic T cells and natural killer cells, allowing these cells to efficiently kill infected or cancerous cells.

C) Interferons

Interferons are proteins that play a role in the immune response, particularly in antiviral defense. They enhance the immune response but do not create pores in cell membranes or directly cause cell destruction through pore formation.

D) Cytokines

Cytokines are signaling molecules that mediate and regulate immunity and inflammation. While they are crucial for immune system communication and function, they do not create pores in cell membranes or directly destroy cells.

Conclusion

Perforins are the only molecules among the options that directly create pores in target cell membranes, leading to cell destruction. The other options—lymphotoxins, interferons, and cytokines—play important roles in the immune response but do not perform the specific function of pore formation necessary for direct cell lysis. Thus, perforins are definitively the correct answer.