Question

Sarah's doctor has detected late-stage malignant ovarian tumors. Which branch of the immune system would respond to these conditions?

A) cell-mediated immune response - Tc cells

B) cell-mediated immune response - B lymphocytes

C) macrophages

D) complement

Answer 1

Cytotoxic T cells respond to malignant tumor cells an kill them. Cancer cells undergo aberrant signaling events that cause phosphorylated signaling molecules to accumulate in them. These phosphorylated signals cause cancer cells to become malignant and also stimulates generation of cytotoxic T cells.

Cytotoxic T cells respond to Antigens that are expressed by processed by antigen presenting cells along with class 1 MHC molecules. Once a cytotoxic T cell binds to the malignant cell antigens presented along with class 1 MHC molecules by T helper cells, they release perforin and granzymes to kill the tumor cell.

B lymphocytes can produce antibodies to tumor cell antigens. However, they are not as efficient as cytotoxic T cells in killing tumor cells. It has also been indicated that B cell may infact increase tumor progression by increasing expression of cytokines like IL-10. Similarly, macrophages can phagocytose cancer cells when in circulation. Macrophages do not give prognosis in late stage cancers. Complement is involved in killing of bacterial pathogens.

Right choice: A) cell-mediated immune response - Tc cells