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5865Одобрявам
Няма "В клетки на паметта". "Т мемори" има. От Т се образуват В клетки (плазмоцити). И това е много просто обяснено. Като за 7-8 клас биология. Има и редица други елементи, взаимодействия и т.н.
Memory T cell subtypes
- Central memory T cells (TCM cells) express CD45RO, C-C chemokine receptor type 7 (CCR7), and L-selectin (CD62L). Central memory T cells also have intermediate to high expression of CD44. This memory subpopulation is commonly found in the lymph nodes and in the peripheral circulation.
- Effector memory T cells (TEM cells) express CD45RO but lack expression of CCR7 and L-selectin. They also have intermediate to high expression of CD44. Because these memory T cells lack the CCR7 lymph node-homing receptors they are found in the peripheral circulation and tissues.TEMRA stands for terminally differentiated effector memory cells re-expressing CD45RA, which is a marker usually found on naive T cells.
- Tissue resident memory T cells (TRM) occupy tissues (skin, lung, gastrointestinal tract, etc.) without recirculating. Some cell surface markers that have been associated with TRM are CD69 and integrin αeβ7 (CD103). However, it is worth noticing that TRM cells found in different tissues express different sets of cell surface markers. While CD103+ TRM cells are found to be restrictedly localized to epithelial and neuronal tissues, TRM cells localized in salivary glands, pancreas and female reproductive tracts in mice express neither CD69 or CD103. TRM cells are thought to play a major role in protective immunity against pathogens. Studies have also suggested a dual role for TRM cells in protection and regulation. Compared to TEM cells, TRM cells secrete higher levels of protective-immunity-related cytokines and express lower levels of the proliferation marker Ki67. It was proposed that these characteristics may help with long-term maintenance of TRM cells, as well as keeping a balance between quick response to antigen invasion and avoidance of unnecessary tissue damage. Dysfunctional TRM cells have been implicated in autoimmune diseases, such as psoriasis, rheumatoid arthritis, inflammatory bowel disease. Specific to TRM lymphocytes are genes involved in lipid metabolism, being highly active, roughly 20- to 30-fold more active than in other types of T-cells.
- Virtual memory T cells (TVM) differ from the other memory subsets in that they do not originate following a strong clonal expansion event. Thus, although this population as a whole is abundant within the peripheral circulation, individual virtual memory T cell clones reside at relatively low frequencies. One theory is that homeostatic proliferation gives rise to this T cell population. Although CD8 virtual memory T cells were the first to be described, it is now known that CD4 virtual memory cells also exist.
There have been numerous other subpopulations of memory T cells suggested. Investigators have studied Stem memory TSCM cells. Like naive T cells, TSCM cells are CD45RO−, CCR7+, CD45RA+, CD62L+ (L-selectin), CD27+, CD28+ and IL-7Rα+, but they also express large amounts of CD95, IL-2Rβ, CXCR3, and LFA-1, and show numerous functional attributes distinctive of memory cells
Отговор с цитат
Първоначално публикувано от Tommorow 
