Isolation and characterization of membrane receptors for pokeweed mitogens from mouse lymphocytes.
The major glycoproteins that bind pokeweek B-cell mitogen (Pa-1) and pokeweed T-cell mitogen (Pa-2) were isolated and identified from bone-marrow-derived lymphocytes (B-cells) and thymus-derived lymphocytes (T-cells) of C3H/He mice. The surfaces of the cells were 125I-labelled by using the enzyme lactoperoxidase, and the plasma membranes were isolated from the 125I-labelled cells. These membranes were solubilized with Triton X-100 and subjected to affinity chromatography on the affinity adsorbent prepared by coupling mitogen Pa-1 or Pa-2 to activated Sepharose 4B. The glycoproteins specifically eluted with di-N-acetylchitobiose from the affinity adsorbents were analysed according to their mobility on polyacrylamide-gel electrophoresis in sodium dodecyl sulphate. These glycoproteins were further identified by immunoprecipitation with specific antisera. Immunoglobulins, possibly immunoglobulins M and D, were identified in the eluate from the B-cell membranes, but they were not detected in the eluate from the T-cell membranes. The histocompatibility-2-complex proteins (H-2D, H-2K and Ia antigens) were found to be major receptor sites for the pokeweed mitogens on both B-cells and T-cells. However, mitogen Pa-1 (B-cell) has a stronger affinity to Ia antigens than does mitogen Pa-2 (T-cell).
D000818:Animals; D001402:B-Lymphocytes / Q000032:analysis; D001665:Binding Sites; D004591:Electrophoresis, Polyacrylamide Gel; D006023:Glycoproteins / Q000302:isolation & purification*; D008214:Lymphocytes / Q000032:analysis* / Q000378:metabolism; D008565:Membrane Proteins / Q000302:isolation & purification*; D051379:Mice; D008934:Mitogens / Q000378:metabolism*; D013601:T-Lymphocytes / Q000032:analysis
D006023:Glycoproteins; D008565:Membrane Proteins; D008934:Mitogens