Journal article

Binding, Internalization, and Degradation of I-125-MultipotentialColony-Stimulating Factor (Interleukin-3) By FDCP-1 Cells

Nicos A Nicola, Donald Metcalf



The kinetic parameters involved in determining the steady-state interaction of Multi-CSF with FDCP-1 cells at 37 degrees C have been determined by kinetic analysis under steady-state conditions and by curve-fitting the rate of approach to steady-state conditions. The two methods are in substantial agreement and yield values of Vr = 28 receptors/cell/min for the rate of appearance of receptors at the cell surface, ke and kt = 0.061 min-1 and 0.0044 min-1 for the rate constants of internalization of occupied and unoccupied receptors, respectively, kh = 0.008 min-1 for the rate constant of degradation of internalized ligand, ka = 2.9 X 10(8) M-1 min-1 for the rate constant of association and kd..

View full abstract

University of Melbourne Researchers


Awarded by National Institutes of Health, Bethesda, MD

Funding Acknowledgements

Linda Peterson and Luba Oddo are thanked for technical assistance, Dr. T. M. Dexter, Paterson Laboratories, Manchester for the FDCP-3 cell line, Dr. J. DeLamarter, Biogen, Switzerland for recombinant IL-3 and Dr. S. Vuk-Pavlovic, Mayo Foundation, Rochester, for making his curve-fitting program available. This work was supported by the National Health and Medical Research Council, Canberra, the Anti-Cancer Council of Victoria, the J. D. and L. Harris Trust Fund and the National Institutes of Health, Bethesda, MD, Grant CA-22556.