Definition of transient ischemic attack. : a brief episode of cerebral ischemia that is usually characterized by temporary blurring of vision, slurring of speech, numbness, paralysis, or syncope and is often predictive of a serious stroke âabbreviation TIA âcalled also ministroke.
Germinal centers are an important part of the B cell humoral immune response, acting as central factories for the generation of affinity matured B cells specialized in producing improved antibodies that effectively recognize infectious agents, and for the production of durable memory B cells.nce these B cells have stopped proliferating, they migrate to the light zone where they are known as centrocytes, and are subjected to selection by follicular helper T (TFH) cells in the presence of follicular dendritic cells (FDCs).
Key points. 1  Germinal centre-independent memory B cells are generated from CD38 + GL7 + activated B cells. 2  These memory B cells may maintain broad reactivity to the activating pathogen. 3  B1a and B1b cells can generate T cell-independent memory B cells. 4  IgG + and IgM + memory B cells have a distinct function.