What happens to B cells during a germinal center reaction?
The germinal centre B cells undergo somatic hypermutation and class switch recombination. Plasma cells and memory B cells with a high-affinity for the original antigen stimuli are produced. These cells are long lived and plasma cells may secrete antibody for weeks after the initial infection.
Do B cells undergo apoptosis?
At the steady state, before or after development of an immune response, B cell apoptosis ensures that the antigen receptor (BCR) on newly produced B cells is functional and does not recognize self-antigens with high avidity. Three sets of membrane molecules stand as crucial regulators of B cell survival.
Which cells are involved in apoptosis of AB cells during its maturation in germinal Centre?
3b, right panel). These results provide physiological evidence that EAF2 is involved in the apoptosis of GC B cells and that lack of EAF2 results in enlarged GC. The increased survival of GC B cells in Eaf2−/− mice may result in an accumulation of non-proliferating B cells.
What specific event is associated with B cell division in germinal centers?
They constitute the primary T-B collaboration event. They proliferate as a result of their activation, which needs at least two events: recognition of antigen and help by T helper cells while recognizing the antigen. The first signal for the activation of B cells in germinal centers is the BCR–antigen interaction.
How are B cells activated in the germinal center?
The first signal for the activation of B cells in germinal centers is the BCR–antigen interaction. Here the antigen is held by the antibody that is attached by its Fc portion to FDC in the light zone of the germinal center. In the dark zone, B cells (centroblasts) proliferate and undergo somatic hypermutation.
How are light zo ne B cells selected by apoptosis?
Light-zo ne B cells underwent apoptosis by default unless they were rescued by positive selection. In contrast, apoptotic dark-zone B cells were highly enriched among cells with genes damaged by random antibody-gene mutations. Germinal centers (GCs) are transient microanatomic structures that form in lymphoid organs during an immune response.
Which is GC zone experiences high rates of apoptosis?
Mayer et al. studied apoptosis reporter mice and found that both GC zones experience very high rates of apoptosis (see the Perspective by Bryant and Hodgkin). However, the underlying mechanisms were distinct and microanatomically segregated. Light-zo ne B cells underwent apoptosis by default unless they were rescued by positive selection.
Why are centroblasts important in the germinal center?
Thus, the homeostatic chemokines are important for BALT-dependent B cell responses in unexpected ways. Germinal center B cells are known as centroblasts when they proliferate, and centrocytes when they stop. Germinal centers have a dark and light zone surrounded by the mantle zone (see germinal center in the tonsil, Figure 3-16 ).
