CD5分子
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CD5 分子
CD5
常用单克隆抗体或代号：T1，UCHT2，T101，Leul
主要表达细胞：T，Thy，BsubC T细胞
分子质量(kDa)和结构：gp67(清除剂受体)
功 能：与CD72结合，T细胞信号转导和增殖，CD5+ B细胞与自身免疫有关
CD5
Belongs to ancient scavenger receptor family
Is physically and functionally coupled with T cell receptor-zeta-CD3 signal transducer complex
CD5+ B cells produce “generalist antibodies” - polyreactive low affinity "natural" antibodies to exogenous antigens (tetanus toxoid, lipopolysaccharide) as well as autoreactive antibodies (ssDNA, thyroglobulin, insulin)
Note: sharks only have polyreactive IgM
Note: monoreactive IgG is produced by < 0.1% of circulating B cells, from positive selection and somatic
point mutation
First line of defense against antigens; have a low activation threshold; are the only line of defense for those who cannot produce specific antibody
Produce antibodies using germ line (non mutated) configuration of gene segments, usually IgM
Production elevated in rheumatoid arthritis (27-52% of circulating B cells vs. 20% normal)
CD5 may serve as a dual receptor, giving either stimulatory or inhibitory signals depending both on the cell type and the development stage
Positive staining (normal): B cells of mantle zone of spleen and lymph nodes; B cells in peritoneal and pleural cavities; almost all T cells;
In fetus, most B cells in spleen and cord blood are CD5 positive
Positive staining (disease): B cell CLL/SLL, mantle cell lymphoma, most T malignancies, thymic carcinomas (70%)
Negative staining: spindle cell thymomas, MALT lymphoma, follicular lymphoma
Micro images: extranodal NK/T cell lymphoma, nasal type, mantle cell lymphoma (figure 3D)
