Immunology Chapter 6 – The development of B-lymphocytes
B-cell vs T-cell
B-cell:
• Development in Bone marrow – generation BCR – negative selection
• Secondary lymphoid organs – positive selection – naïve B cells
• Activation by intact antigen -- Isotype switching and affinity maturation
• Effector (plasma cell) and memory B cells
T-cell:
• Development in Thymus – generation TCR – positive and negative selection
• Secondary lymphoid organs – naïve T cells
• Activation by processed antigen via MHC plus peptide
• Effector and memory T cells
B-cell development
Development of B-cell receptor in the bone marrow (BCR
generation) → remove B-cells which are harmful to the
human body (negative selection) (occurs in primary
lymphoid organs)→ promotion of immature B cells to become mature B cells (positive
selection) (occurs in secondary lymphoid organs) → mature B-cells recirculate
between blood and lymphoid organs to search for their antigen --> B cells are
activated by binding to intact antigen. They start to become effector cells and
produce antibodies
Development of B cells in the bone marrow
Stem cells in bone marrow: DNA of the heavy and light
chain has not been rearranged yet. So, this is the
germline configuration
→ B-cell precursor (early pro-B-cell):
Heavy chain: somatic recombination of the heavy chain by
expression of RAG. DJ rearrangements on both chromosomes
Light chain: no somatic recombination. So, this is the germline
configuration
→ (Late) pro-B-cell:
Heavy chain: somatic recombination of the heavy chain by
expression of RAG. V-DJ rearrangements on first chromosome
Light chain: no somatic recombination. So, this is the germline
configuration
→ Large pre-B-cell:
Heavy chain: VDJ rearranged.
Light chain: no somatic recombination. So, this is the germline configuration
• Protein production of the heavy chain
• First checkpoint for the function heavy chain: can the heavy chain interact with
the light chain (heavy + light = pre-B-cell receptor)? But the light chain has not
B-cell vs T-cell
B-cell:
• Development in Bone marrow – generation BCR – negative selection
• Secondary lymphoid organs – positive selection – naïve B cells
• Activation by intact antigen -- Isotype switching and affinity maturation
• Effector (plasma cell) and memory B cells
T-cell:
• Development in Thymus – generation TCR – positive and negative selection
• Secondary lymphoid organs – naïve T cells
• Activation by processed antigen via MHC plus peptide
• Effector and memory T cells
B-cell development
Development of B-cell receptor in the bone marrow (BCR
generation) → remove B-cells which are harmful to the
human body (negative selection) (occurs in primary
lymphoid organs)→ promotion of immature B cells to become mature B cells (positive
selection) (occurs in secondary lymphoid organs) → mature B-cells recirculate
between blood and lymphoid organs to search for their antigen --> B cells are
activated by binding to intact antigen. They start to become effector cells and
produce antibodies
Development of B cells in the bone marrow
Stem cells in bone marrow: DNA of the heavy and light
chain has not been rearranged yet. So, this is the
germline configuration
→ B-cell precursor (early pro-B-cell):
Heavy chain: somatic recombination of the heavy chain by
expression of RAG. DJ rearrangements on both chromosomes
Light chain: no somatic recombination. So, this is the germline
configuration
→ (Late) pro-B-cell:
Heavy chain: somatic recombination of the heavy chain by
expression of RAG. V-DJ rearrangements on first chromosome
Light chain: no somatic recombination. So, this is the germline
configuration
→ Large pre-B-cell:
Heavy chain: VDJ rearranged.
Light chain: no somatic recombination. So, this is the germline configuration
• Protein production of the heavy chain
• First checkpoint for the function heavy chain: can the heavy chain interact with
the light chain (heavy + light = pre-B-cell receptor)? But the light chain has not
