Cell surface antigen CD5 is a marker for activated human B cells.
A minor subset of B cells which in vivo express the surface antigen CD5, has attracted much attention because of its involvement in autoimmune responses. On the basis of observations showing self-renewal capacity of such cells in mice and also the absence of a substantial change of CD5 phenotype during B cell activation in vitro, the CD5+ B cells are now generally considered to represent a separate cell lineage. In the present study, CD5- B cells were isolated by cell sorter and then stimulated in vitro with mutagenized EL4 thymoma cells in the presence of T cell supernatant. About 70% of the B cells were CD5+ after 3 days. Thus, the CD5 antigen behaves as a B cell activation marker. In our system we found that the frequency of rheumatoid factor-producing B cells was on average three times higher in CD5+ than in CD5- B cells isolated ex vivo from human peripheral blood. Most likely this reflects frequent activation of such autoreactive B cells in vivo.
Werner-Favre
C
C
Division of Hematology, Geneva University Hospital, Switzerland.
Vischer
T L
TL
Wohlwend
D
D
Zubler
R H
RH
D000917:Antibody Formation; D018951:Antigens, CD20; D000943:Antigens, Differentiation / Q000276:immunology*; D000944:Antigens, Differentiation, B-Lymphocyte / Q000032:analysis; D001402:B-Lymphocytes / Q000145:classification / Q000276:immunology*; D018956:CD5 Antigens; D002478:Cells, Cultured; D005434:Flow Cytometry; D006801:Humans; D008213:Lymphocyte Activation; D012217:Rheumatoid Factor / Q000096:biosynthesis
D018951:Antigens, CD20; D000943:Antigens, Differentiation; D000944:Antigens, Differentiation, B-Lymphocyte; D018956:CD5 Antigens; D012217:Rheumatoid Factor