First a review

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First a review

• Adopt as a perspective that
• One B-cell produces one antibody
• Make that perspective more exacting
• One B-cell produces one idiotype.
• Cassettes (V, J, D,) (aka gene segments) fuse
  (to make an idiotype).
• Fusing occurs because RAG recognizes one turn/two
  turn signals on cassettes.
• CDR3 develops through junctional flexibility
  (trimming) and addition of P N nucleotides
  (expanding).
• CDR1 and CDR2 (especially) and CDR3 become more
  varied because of somatic hypermutation.
  
  

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First a review now with images

• And, I will use images from a different source.
• Remember to be critical of what interpretative
  drawings convey

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First a review now with images
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First a review still with images

• RAG what does it do? how does it work?

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First a review still with more images

• RAG what does it do? how does it work?
• what about PN nucleotides?

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PART IV (some new stuff)

• How do immunoglobulins assemble?
• Some immunoglobulins are in the surface membrane
  of immature B-cells while other immunoglobulins
  of the same idiotype are secreted by mature
  B-cells. Whats the difference?
• Similarly, identical variable regions can be
  shared among different isotypes. How?
• B-cells are diploids with two sets of genetic
  instructions. How does just one set get
  expressed?

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How do immunoglobulins assemble?
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Some immunoglobulins are in the surface membrane
of immature B-cells while other immunoglobulins
of the same idiotype are secreted by mature
B-cells. Whats the difference?
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Similarly, identical variable regions can be
shared among different isotypes. How?
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B-cells are diploids with two sets of genetic
instructions. How does just one set get
expressed?
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The general scheme of B-cell development

• STEM CELL
• ?
• pro (genitor) Bcell
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• pre Bcell
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• Ag-selected (? stimulated)- Bcell
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• Ab secreting plasma cell