T cell in adults?

[m25]

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According TBR, removal of thymus( which is the location of T cell maturation during early development) from adult human would not have much effect on immune system because T cells have already matured by the time they reach adulthood.
My question is, does that mean T cell is not continuously produced in adults? Or do T cells still divide via mitosis without needing it to happen in the thymus?

And what would be the effect of removing bone marrow(location of B cell maturation) from adult?

 

[Czarcasm]

According TBR, removal of thymus( which is the location of T cell maturation during early development) from adult human would not have much effect on immune system because T cells have already matured by the time they reach adulthood.
My question is, does that mean T cell is not continuously produced in adults? Or do T cells still divide via mitosis without needing it to happen in the thymus?

And what would be the effect of removing bone marrow(location of B cell maturation) from adult?

During the early process of specialized immune cell development and maturation, our immune cells go through a screening and selection process that eliminates a majority of immature CD4+ or CD8+ cells (the precursors of these cells migrated from our bone marrow to the thymus during early development). In the thymus, this screening process involves apoptosis (programmed cell death) and the cells that are induced to die are generally those that target "self" or cell markers on our own cells. This is important because it prevents autoimmune responses. By adulthood, the thymus shrinks since the majority of these immature T cells have been processed and been freed from the thymus, where they relocate and maintain residence in various lymph tissues such as lymph nodes or the spleen; here they await activation by a specialized macrophages called a dendritic cells. This activation process converts a specific naive CD4+ and CD8+ cells into active/mature T helper or T Killer cells, as well as a clone of memory cells (which help induce a quicker immune response upon reactivation). Meanwhile, we still have several naive T cells that maintain residence in lympathic tissue that can remain unstimulated/activated throughout our lives.

The basic takeaway from all this is that because a majority of our naive T cells have already been freed from the thymus during the screening process, its removal in adulthood is less hazardous. For childrem this process is still on going, so in children, removal of the thymus would be very problematic and those children would have a weak immune system as a result.

 

[m25]

During the early process of specialized immune cell development and maturation, our immune cells go through a screening and selection process that eliminates a majority of immature CD4+ or CD8+ cells (the precursors of these cells migrated from our bone marrow to the thymus during early development). In the thymus, this screening process involves apoptosis (programmed cell death) and the cells that are induced to die are generally those that target "self" or cell markers on our own cells. This is important because it prevents autoimmune responses. By adulthood, the thymus shrinks since the majority of these immature T cells have been processed and been freed from the thymus, where they relocate and maintain residence in various lymph tissues such as lymph nodes or the spleen; here they await activation by a specialized macrophages called a dendritic cells. This activation process converts a specific naive CD4+ and CD8+ cells into active/mature T helper or T Killer cells, as well as a clone of memory cells (which help induce a quicker immune response upon reactivation). Meanwhile, we still have several naive T cells that maintain residence in lympathic tissue that can remain unstimulated/activated throughout our lives.

The basic takeaway from all this is that because a majority of our naive T cells have already been freed from the thymus during the screening process, its removal in adulthood is less hazardous. For childrem this process is still on going, so in children, removal of the thymus would be very problematic and those children would have a weak immune system as a result.

So you are saying that basically thymus is a location where T cells are screened and proceeded, correct? So once adulthood is reached, do those "qualified" T cells that was screened by thymus able to proliferate on their own via mitosis or something?

And what would happen if we remove bone marrow from adult? Would B cell production be compromised, or would it mirror the response of removing thymus, ie, immunity will not be compromised?