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Antigenic escape, immune escape, immune evasion or escape mutation occurs when the immune system of a host, especially of a human being, is unable to respond to an infectious agent: the host's immune system is no longer able to recognize and eliminate a pathogen, such as a virus.
The precise role of double-stranded (ds)RNA is still widely investigated as a central player in the Interferon System. Groups have found that positive-strand RNA viruses and dsRNA viruses produced significant amounts of dsRNA, but the precise methods mammalian cells leverage to distinguish between self vs. non-self dsRNA have yet to be uncovered.
There are several mechanisms that lead to escape of cancer cells to immune system, for example downregulation or loss of expression of classical MHC class I (HLA-A, HLA-B- HLA-C) [7] [4] which is essential for effective T cell-mediated immune response (appears in up to 90% of tumours [7]), development of cancer microenvironment which has ...
Antigenic variation or antigenic alteration refers to the mechanism by which an infectious agent such as a protozoan, bacterium or virus alters the proteins or carbohydrates on its surface and thus avoids a host immune response, making it one of the mechanisms of antigenic escape. It is related to phase variation. Antigenic variation not only ...
Immune tolerance encompasses the range of physiological mechanisms by which the body reduces or eliminates an immune response to particular agents. It is used to describe the phenomenon underlying discrimination of self from non-self, suppressing allergic responses, allowing chronic infection instead of rejection and elimination, and preventing ...
If the zebra sees a lion closing in for the kill, the stress response is activated as a means to escape its predator. The escape requires intense muscular effort, supported by all of the body's systems. The sympathetic nervous system's activation provides for these needs. A similar example involving fight is of a cat about to be attacked by a dog.
Lizard tail autotomy can distract predators, continuing to writhe while the lizard makes its escape. Some animals are capable of autotomy (self-amputation), shedding one of their own appendages in a last-ditch attempt to elude a predator's grasp or to distract the predator and thereby allow escape. The lost body part may be regenerated later.
There is also an increasing body of evidence that points to a positive contribution of tonic immobility in human functioning. Thus, defensive immobilization is hypothesized to have played a crucial role in the evolution of human parent-child attachment, [ 61 ] sustained attention and suggestibility, [ 62 ] [ 63 ] REM sleep [ 64 ] and theory of ...