Immunology developing B cells

Posotive and negative selection occurs in the thymus.

Immature T cells move from the Bone Marrow to the tymus where they are posotivly and negativly selected and this is the basis of Tolerance. T cells that bind Too Weakly to the MHC antigen complex are killed by apoptosis. T cells that bind too strongly are also killed by apoptosis. Those that lie between are selected.

This is important as T cell binding too weakly cant raise immune awarness and cells that vbind too strongly cause autoimmune diseases.

Look up T cell anergy which is things like blocking of the receptor deletion of the T cell etc. Try the book immunobilogy By c Janeway or "the immune system" by Peter Parham both published by garland science.

ok this is a very basic overview as its a long subject and needs to be read rather than asked on this.

good luck

The pre-B-cell stage is a key checkpoint during B-cell differentiation. Pre-B Cells without a function pre-BCR die by apoptosis.