MIMG 185A Lecture Notes - Lecture 4: C-C Chemokine Receptor Type 7, Cxcl13, Ccl21
13 Jul 2018
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Isotype switching - recombination event at the genomic level on both chromosomes: everything that is after the constant region used, mu and delta show up on the same mrna and are expressed depending on alternative splicing. The only two classes that can be coexpressed: 12/23 rule - can only recombine two segments if one has a 12 bp spacer and the other has a 23 bp spacer, can"t have the same number bp spacer. Marginal zone b cells: originate in the bone marrow, found in marginal zone of the spleen, contain somatic mutations, respond to polysaccharide ags of blood-borne bacteria. Ccl21 and cxcl13 are chemokines that direct cell movement along a concentration gradient: ccl21 - t zone, cxcl13 - b zone. Na ve b cells express cxcr5 when they enter the ln. Fdcs make cxcl3 which recruit sb cells to the b cell zone.
