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Cellular senescence is a phenomenon characterized by the cessation of cell division. [ 1 ][ 2 ][ 3 ] In their experiments during the early 1960s, Leonard Hayflick and Paul Moorhead found that normal human fetal fibroblasts in culture reach a maximum of approximately 50 cell population doublings before becoming senescent. [ 4 ][ 5 ][ 6 ] This ...
Immune system. The immune system is a network of biological systems that protects an organism from diseases. It detects and responds to a wide variety of pathogens, from viruses to parasitic worms, as well as cancer cells and objects such as wood splinters, distinguishing them from the organism's own healthy tissue.
Immunosenescence is the gradual deterioration of the immune system, brought on by natural age advancement. A 2020 review concluded that the adaptive immune system is affected more than the innate immune system. [1] Immunosenescence involves both the host's capacity to respond to infections and the development of long-term immune memory.
Memory B cell. B lymphocytes are the cells of the immune system that make antibodies to invading pathogens like viruses. They form memory cells that remember the same pathogen for faster antibody production in future infections. In immunology, a memory B cell (MBC) is a type of B lymphocyte that forms part of the adaptive immune system.
Upon activation, B cells produce antibodies, each of which recognize a unique antigen, and neutralizing specific pathogens. [3] Antigen and antibody binding would cause five different protective mechanisms: Agglutination: Reduces number of infectious units to be dealt with; Activation of complement: Cause inflammation and cell lysis
Long-lived plasma cell. Long-lived plasma cells (LLPCs) are a distinct subset of plasma cells that play a crucial role in maintaining humoral memory and long-term immunity. [1] They continuously produce and secrete high-affinity antibodies into the bloodstream, conversely to memory B cells, which are quiescent and respond quickly to antigens ...
GC B cells that are best able to present antigen to T follicular helper cells and produce the strongest B cell receptor signal are positively selected in the light zone of the germinal center. [4] Therefore, positive selection of GC B cells in the light zone results in B cells that express antibodies with high affinity for the antigen. [3]
Senescence (/ s ɪ ˈ n ɛ s ə n s /) or biological aging is the gradual deterioration of functional characteristics in living organisms. Whole organism senescence involves an increase in death rates or a decrease in fecundity with increasing age, at least in the later part of an organism's life cycle.