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Exhaustion of 'memory' CD8 T cells

User Ben Jones
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Final answer:

Memory CD8 T cells are long-lived immune cells that persist after an infection and can rapidly respond upon re-exposure to the same pathogen. They contrast with effector T cells, which die after the pathogen is cleared. Memory T cell exhaustion can lead to decreased immune response and increased susceptibility to diseases such as HIV/AIDS.

Step-by-step explanation:

Exhaustion of Memory CD8 T CellsMemory T cells are a subset of T lymphocytes that play a critical role in the immune response to pathogens. After the clearance of an infection, cytotoxic T cells, which are capable of destroying infected cells and the viruses they contain, mostly die off. In contrast, a portion of these cells remain as long-lived memory cells, poised to respond swiftly to future exposures to the same pathogen. These memory cells can rapidly proliferate and produce many cytotoxic T cells that are specific to an antigen, upon re-exposure to the same pathogen, enhancing the body’s immune defense.

MHC class I molecules, which are found on the surface of almost all body cells, bind to the CD8 molecule on T cells. This interaction is necessary for the proper functioning of CD8+ cytotoxic T cells. It is important to note that a decrease in helper T cells, especially CD4+ T cells, can lead to immune deficiencies, as seen in diseases such as HIV/AIDS. An HIV infection can lead to a severe reduction in CD4+ T cells, impairing adaptive immune functions and making the body vulnerable to opportunistic infections.

Furthermore, acute restraint stress has been shown to increase the numbers of memory and effector helper T cells, which may contribute to the heightened immune response upon antigen re-exposure. The memory cells, unlike effector cells, do not respond during the primary immune response but can become effector cells quickly upon re-exposure to the antigen. In contrast to effector cells, which undergo apoptosis after the infection subsides, memory cells persist in the circulation, retaining the immunological memory of the pathogen.

User Pixelfreak
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