Immune evasion

Definition

Immune evasion refers to the strategies employed by pathogens, including viruses and cancer cells, to avoid detection and elimination by the host's immune system. These mechanisms can include altering surface proteins, producing immune-suppressive molecules, or mimicking host cells, allowing pathogens to persist and proliferate despite an active immune response. Understanding these strategies is crucial for developing effective therapies and vaccines.

5 Must Know Facts For Your Next Test

1. HIV employs several strategies for immune evasion, including high mutation rates and glycan shielding of its envelope proteins, which help it escape recognition by antibodies.
2. Cancer cells can evade the immune system by downregulating the expression of major histocompatibility complex (MHC) molecules, preventing T cells from recognizing and attacking them.
3. Pathogens like bacteria and viruses may release soluble factors that interfere with immune signaling pathways, effectively dampening the host's immune response.
4. The concept of 'immune escape' is critical in understanding why certain cancers are able to progress despite the presence of an immune response, leading to research into immunotherapies.
5. Research into immune evasion has led to innovative therapies, such as immune checkpoint inhibitors, which aim to reinvigorate exhausted T cells in cancer patients.

Review Questions

• How do viruses like HIV utilize immune evasion strategies to persist in the host?
  • Viruses such as HIV utilize immune evasion strategies by employing high mutation rates that allow them to change their surface antigens rapidly. This continuous alteration makes it difficult for the host's immune system to recognize and target the virus effectively. Additionally, HIV can shield its envelope proteins with glycans, further preventing neutralizing antibodies from binding and promoting persistence within the host.
• What are some common mechanisms through which tumor cells evade immune detection?
  • Tumor cells can evade immune detection through several mechanisms. They may downregulate major histocompatibility complex (MHC) molecules, which prevents T cells from recognizing them as foreign. Additionally, tumors can produce immunosuppressive cytokines that inhibit T cell activation and promote T cell exhaustion. These tactics allow tumors to grow and proliferate despite the presence of an active immune response.
• Evaluate the impact of understanding immune evasion on the development of cancer immunotherapies.
  • Understanding immune evasion significantly impacts the development of cancer immunotherapies by providing insights into how tumors escape detection and elimination by the immune system. This knowledge has led to innovative treatments such as immune checkpoint inhibitors, which block inhibitory signals on T cells and restore their ability to attack tumors. By targeting specific pathways involved in immune evasion, researchers are enhancing the effectiveness of immunotherapies and improving patient outcomes in cancer treatment.

Related terms

Antigenic Variation: A mechanism where pathogens change their surface antigens to evade recognition by the immune system, making it difficult for the host to mount an effective response.

T Cell Exhaustion: A state of dysfunction that occurs in T cells during chronic infections or cancer, where T cells lose their ability to effectively respond to and eliminate infected or tumor cells.

Immune Checkpoints: Regulatory pathways in the immune system that can be manipulated by tumors or pathogens to inhibit immune responses, allowing them to evade detection.