Brain and B Cells

In contrast to T cells, in different immunopathologies, the brain provides a fostering envkonment to B cells. Primary central nervous system (CNS) lymphomas are usually of B cell origin. The cerebrospinal fluid (CSF) of patients with chronic infections and autoimmune diseases of the CNS typically contains remarkably stable oligoclonal Ig bands. In the CNS of multiple sclerosis patients, clonally expanded B cells and plasma cells persist. Ectopic B cell follicles develop in the meninges of patients with secondary progressive MS, and B cell differentiation may be recapitulated in the CNS of MS patients (Krumbholz et al., 2006) (see Chapters 18-24). 

Monomeric high-affinity IL-4 receptors (CD 124) are found on T and B cells, macrophages, mast cells, muscle cells, neuroblasts, stromal cells (brain and bone marrow), myeloid cells, granulocytes, megakaryocytes, hematopoietic progenitor cells, NK cells, fibroblasts, and epithelial and endothelial celis. About 300 IL-4 receptors per cell are found on B and T lymphocytes, a number that increases to 100 to 1000 receptors per cell with cell maturation and activation. ... 

The p35 subunit of IL-12 is produced by T and B cells, NK cells, neutrophils, monocytes, and macrophages (at least in the mouse). The p40 subunit is produced mainly by B lymphocytes, activated monocytes, and dendritic cells (including epidermal Langerhans cells). Consequently the principal sources of IL-12 are B cells and monocytes and/or macrophages (Figure 22-20). In the brain, microglia-like cells are the primary producers of the p40 transcripts. In contrast, the IL-12 p35 gene is constitutively expressed in the brain at a very low level. ... 

The RAF receptor is a MW 48 kD, G-protein-coupled single 342 amino acid protein that shows structural characteristics of the rhodopsin gene family. The human, guinea pig, and rat receptors have been cloned and characterized as a seven-transmembrane receptor that induces phos-phoinositol turnover. The receptor shows wide tissue distribution being expressed in lung, kidney, liver, spleen, small intestine, and brain. In leukocytes, it is expressed on platelets, neutrophils, monocytes, and B cells but not on resting T cells and natural killer cell lines. Human monocytes treated with IFN-y show a two- to sixfold increase in RAF receptor expression compared to untreated cells. 

Figure 6.1 The basic constituents and structures of adult brain tissue, (a) Neuron and glial cells in brain and (b) synaptic connections...

ER B 14q22-q24 530 aa, 583 aa, further isoforms 17p-Estradiol (E2) AGGTCA Ovary, testis (Sertoli and Leydig cells, efferent ducts), prostate, bone, thymus, spleen, brain... 

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