Expression of novel interleukin 2 binding molecules and their functional roles in human B cell differentiation.
Expressions and functional roles of novel IL-2 binding molecules (p70, 75) in the differentiation of B cells into Ig secreting cells were explored by using human several B cell lines and tonsillar B cells. Affinity-crosslinking studies revealed that five of nine B cell lines expressed p70 and p75 without detectable Tac antigen (p55) expression and the expression was associated with B cell maturation. In tonsillar B cells, small high-density B cells did not express p70 and p75, whereas large low-density B cells, which were thought to be activated in vivo, expressed them. Binding assays of radiolabeled IL-2 showed that the affinity of these molecules was intermediate (kD = 1-3 nM, 700-3,000 sites/cell). Furthermore, high concentrations of IL-2 (greater than 100 U/ml) induced Ig productions in large B cells and two of five cell lines. These results taken together suggest that B cells may express novel IL-2 binding molecules, associated with B cell differentiation and differentiate into Ig secreting cells by IL-2 through novel IL-2 binding molecules.
Tanaka
T
T
Third Department of Internal Medicine, Osaka University, Japan.
Saiki
O
O
Doi
S
S
Suemura
M
M
Negoro
S
S
Kishimoto
S
S
D000954:Antigens, Surface / Q000096:biosynthesis; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D002454:Cell Differentiation; D002460:Cell Line; D004306:Dose-Response Relationship, Immunologic; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis; D007376:Interleukin-2 / Q000378:metabolism* / Q000502:physiology; D007700:Kinetics; D008213:Lymphocyte Activation; D008970:Molecular Weight; D011971:Receptors, Immunologic / Q000302:isolation & purification* / Q000502:physiology; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000954:Antigens, Surface; D007136:Immunoglobulins; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7