Lateral diffusion measurements give evidence for association of the Tac peptide of the IL-2 receptor with the T27 peptide in the plasma membrane of HUT-102-B2 T cells.
Fluorescence photobleaching recovery measurements show that the F1-IgG-labeled Tac peptide of the IL-2R can diffuse in the plane of the membrane of HUT-102-B2 T lymphocytes, with a mean diffusion coefficient of 2 to 3 x 10(-10) cm2s-1. Although only a fraction (mean 37%) of the Tac peptides is mobile on any given cell, lateral diffusion of the Tac peptide can be measured in 94% of cells examined. In contrast, the 95-kDa peptide, T27, is 90 to 100% immobilized in cells labeled with OKT27. Immobilization of T27 also affects the lateral diffusion of the Tac peptide, because the Tac peptide is immobile in more than 30% of cells pretreated with OKT27 and then labeled with anti-Tac IgG. The effect is specific for OKT27 to the extent that pretreatment with an anti-HLA mAb does not immobilize the Tac peptide. It appears, then, that Tac and T27 peptide not only are in proximity on HUT-102-B2 lymphocyte membranes but also interact physically in situ.
Edidin
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Department of Biology, Johns Hopkins University, Baltimore, MD 21218.
Aszalos
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A
Damjanovich
S
S
Waldmann
T A
TA
D000911:Antibodies, Monoclonal / Q000502:physiology; D000954:Antigens, Surface / Q000276:immunology / Q000378:metabolism*; D002460:Cell Line; D004058:Diffusion; D006680:HLA Antigens / Q000276:immunology; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism*; D008565:Membrane Proteins / Q000276:immunology / Q000378:metabolism*; D011971:Receptors, Immunologic / Q000378:metabolism*; D015375:Receptors, Interleukin-2; D013601:T-Lymphocytes / Q000378:metabolism*; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7
D000911:Antibodies, Monoclonal; D000954:Antigens, Surface; D006680:HLA Antigens; D007376:Interleukin-2; D008565:Membrane Proteins; D011971:Receptors, Immunologic; D015375:Receptors, Interleukin-2; D018127:Tumor Necrosis Factor Receptor Superfamily, Member 7