Characterization of receptors for a T cell derived cytosolic BCGF-60kD.
A 60 kD cytosolic protein derived from human peripheral blood T cells has been shown to mediate proliferation in BCGF responsive long term B cell cultures. In this report, we show cBCGF-60kD can be radioiodinated with no significant loss of biologic activity and bound specifically to B cell surface membrane receptors. The time course of 125I-cBCGF-60kD demonstrated that binding reached saturation within 40 minutes, (T 1/2 of 15 minutes). Scatchard analyses of ligand-receptor binding identified a high affinity receptor (0.6(-3) x 10(3) receptors per cell) having a dissociation constant of 1-8 pM. Partial cross-competition experiments with a secreted, T cell derived BCGF-12kD identified a potential receptor heterogeneity on BCGF responsive B cell line.
Mehta
S
S
Department of Molecular Pathology, M.D. Anderson Cancer Center, Houston, TX.
Grant
S
S
Sandler
R
R
Sharma
S
S
Ford
R
R
Maizel
A
A
D001402:B-Lymphocytes / Q000378:metabolism*; D001667:Binding, Competitive; D003600:Cytosol / Q000378:metabolism*; D006801:Humans; D008970:Molecular Weight; D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen / Q000378:metabolism*
D019948:Receptors, Interleukin-4; D011975:Receptors, Mitogen