Immunosuppression

Definition

Immunosuppression refers to the reduction or complete suppression of the immune response, which can result from medical treatments, diseases, or other factors. This phenomenon is particularly relevant in the context of tumors, where cancer cells often develop mechanisms to evade detection and destruction by the immune system, allowing them to grow and proliferate unchecked.

5 Must Know Facts For Your Next Test

1. Immunosuppression can be induced intentionally through therapies such as corticosteroids or chemotherapy to prevent transplant rejection or manage autoimmune diseases.
2. Tumors can exploit immunosuppression by releasing factors that inhibit immune cell function, such as transforming growth factor-beta (TGF-β) and interleukin-10 (IL-10).
3. The presence of regulatory T cells (Tregs) within the tumor microenvironment is a key mechanism through which immunosuppression occurs, as they suppress the activity of effector T cells.
4. Checkpoint inhibitors are a class of drugs in immunotherapy that aim to counteract immunosuppression by blocking proteins that inhibit immune responses, thus reactivating T cells against tumors.
5. Chronic inflammation associated with tumors can also contribute to immunosuppression, as it creates an environment that favors tumor progression while dampening effective immune responses.

Review Questions

• How does immunosuppression facilitate tumor immune evasion, and what role do specific cytokines play in this process?
  • Immunosuppression facilitates tumor immune evasion by weakening the body's ability to recognize and attack cancer cells. Specific cytokines like TGF-β and IL-10 are secreted by tumors and other cells in the tumor microenvironment to suppress the activation and proliferation of effector T cells. This creates an environment where cancer cells can proliferate without being targeted by the immune system, making it crucial for understanding cancer progression.
• Discuss how regulatory T cells (Tregs) contribute to immunosuppression in tumors and the implications for cancer treatment.
  • Regulatory T cells (Tregs) play a significant role in promoting immunosuppression within the tumor microenvironment by inhibiting effector T cell activity. Their presence can lead to a reduced anti-tumor response, making it harder for the immune system to target and destroy cancer cells. Understanding this relationship is important for developing therapies that can either reduce Treg function or enhance effector T cell activity, ultimately improving cancer treatment outcomes.
• Evaluate the effectiveness of checkpoint inhibitors in overcoming immunosuppression and how they reshape the landscape of cancer immunotherapy.
  • Checkpoint inhibitors have revolutionized cancer immunotherapy by specifically targeting and blocking pathways that lead to immunosuppression. By inhibiting proteins like PD-1 or CTLA-4, these drugs reactivate exhausted T cells, allowing them to effectively attack tumors. This approach has shown significant success in various cancers but also highlights the complexity of tumor biology, where not all patients respond favorably. Ongoing research aims to better understand resistance mechanisms and enhance the efficacy of these treatments.

Related terms

Immune evasion: The strategies used by tumor cells to avoid detection and destruction by the immune system, enabling their survival and growth.

Cytokines:

Signaling proteins released by cells that are crucial in mediating and regulating immunity, inflammation, and hematopoiesis, often involved in the communication between immune cells.

Immunotherapy: A type of cancer treatment that uses the body's immune system to fight cancer, often aimed at reversing immunosuppression or enhancing the immune response against tumor cells.