Immune evasion

Definition

Immune evasion refers to the strategies employed by pathogens or cancer cells to avoid detection and destruction by the host's immune system. These strategies can include altering surface proteins, producing immunosuppressive molecules, or creating a microenvironment that inhibits immune responses. Understanding immune evasion is crucial for developing effective therapies, particularly in the realm of cell-based immunotherapies, where overcoming these mechanisms can enhance treatment efficacy.

5 Must Know Facts For Your Next Test

1. Cancer cells can mutate their surface antigens to escape recognition by T-cells, effectively hiding from the immune system.
2. Pathogens like viruses and bacteria may produce proteins that interfere with antigen presentation, diminishing the ability of immune cells to recognize infected cells.
3. Some tumors can secrete immunosuppressive cytokines that inhibit the activity of immune cells, creating a protective environment around themselves.
4. Certain types of cancer exploit regulatory T-cells to suppress anti-tumor immunity, allowing for continued growth and metastasis.
5. Cell-based immunotherapies aim to modify or enhance immune cells, such as CAR T-cells, to target and eliminate cells that employ immune evasion tactics.

Review Questions

• How do cancer cells employ immune evasion strategies to avoid detection by the immune system?
  • Cancer cells often alter their surface antigens through mutations, making it difficult for T-cells to recognize them as threats. They may also downregulate major histocompatibility complex (MHC) molecules that present antigens to immune cells. This combination of tactics allows cancer cells to evade surveillance and continue proliferating without being targeted by the host's immune response.
• Discuss the role of the tumor microenvironment in facilitating immune evasion in cancer therapies.
  • The tumor microenvironment plays a critical role in immune evasion by providing a supportive niche for cancer cells. It can harbor immunosuppressive factors like regulatory T-cells and certain cytokines that dampen the activity of effector T-cells. This creates a barrier against effective immunotherapy, making it essential for treatments to not only target the tumor directly but also modify the surrounding environment to restore immune functionality.
• Evaluate how overcoming immune evasion mechanisms can improve the effectiveness of cell-based immunotherapies.
  • By addressing immune evasion strategies, such as enhancing antigen presentation or blocking immunosuppressive signals in the tumor microenvironment, cell-based immunotherapies can become significantly more effective. Techniques like engineering CAR T-cells to resist suppression from regulatory T-cells or incorporating checkpoint inhibitors into treatment regimens allow these therapies to restore robust immune responses against tumors. Ultimately, tackling these challenges is crucial for achieving long-lasting responses and improving patient outcomes.

Related terms

Immunotherapy: A treatment method that uses the body's immune system to fight diseases, particularly cancer, by enhancing or restoring immune function.

Checkpoint Inhibitors: Drugs that block proteins which prevent the immune system from attacking cancer cells, thereby enhancing the immune response against tumors.

Tumor Microenvironment: The complex environment surrounding a tumor, consisting of various cell types, signaling molecules, and extracellular matrix, which can influence tumor behavior and immune responses.