Expression and the functional role of a p70/75 interleukin 2-binding molecule in human B cell.
Expression of p70/75 IL-2-binding molecules and their functional roles in induction of Ig secretion by IL-2 were examined in human B cells. IL-2, at high concentrations induced higher levels of Ig secretion in Staphylococcus aureus strain Cowan I (SAC)-activated B cells than at low concentrations. About 50% of SAC-activated B cells, lacking Tac antigen, were also responsive to Ig secretion by IL-2, although the required dose of IL-2 was higher than that for Tac-positive B cells. H-31 antibody which recognizes Tac antigen did not inhibit the induction of Ig secretion by high concentrations of IL-2 in both Tac-negative and Tac-positive B cells, suggesting that IL-2 might induce Ig secretion through a receptor distinct from Tac antigens. In contrast, IL-2 was ineffective in the absence of SAC stimulation even at high concentrations. Upon analysis by SDS-PAGE, p70/75 IL-2-binding molecules were detected on Tac-negative SAC-activated B cells. Similar IL-2-binding molecules distinct from Tac antigen (p55) were detected in both Tac-positive B and T cells. However, neither p55 nor p70/75 IL-2-binding molecules could be detected in the absence of SAC stimulation. These observations suggest that p70/75 IL-2 binding molecules are induced in human B-cells in the presence or absence of Tac antigen by SAC stimulation and these determinants play an important function in the transduction of IL-2 associated signal for B cell differentiation.
Saiki
O
O
Third Department of Internal Medicine, Osaka University Hospital, Japan.
Tanaka
T
T
Doi
S
S
Kishimoto
S
S
D000911:Antibodies, Monoclonal / Q000494:pharmacology; D000954:Antigens, Surface / Q000032:analysis / Q000276:immunology; D001402:B-Lymphocytes / Q000145:classification / Q000378:metabolism*; D001667:Binding, Competitive; D004591:Electrophoresis, Polyacrylamide Gel; D005434:Flow Cytometry; D006801:Humans; D007136:Immunoglobulins / Q000096:biosynthesis; D007376:Interleukin-2 / Q000378:metabolism* / Q000494:pharmacology; D008213:Lymphocyte Activation; D010641:Phenotype; D011971:Receptors, Immunologic / Q000032:analysis* / Q000502:physiology; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D007136:Immunoglobulins; D007376:Interleukin-2; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7