Centrifugation assay of IgE-mediated cell adhesion to antigen-coated gels

Authors

  • Lily Chu,

    1. School of Chemical Engineering, Cornell University, Ithaca, NY 14853
    Current affiliation:
    1. Dept. of Chemical Engineering, Univ. of Illinois at Urbana-Champaign, Urbana, IL 61801
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  • Linda A. Tempelman,

    1. School of Chemical Engineering, Cornell University, Ithaca, NY 14853
    Current affiliation:
    1. Naval Research Lab., Center for Bio/Molecular Science and Engineering, Code 6900, Washington, DC 20375
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  • Cynthia Miller,

    1. School of Chemical Engineering, Cornell University, Ithaca, NY 14853
    Current affiliation:
    1. Air Products and Chemicals Inc., P.O. Box 7119, Cumberland, RI 02864
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  • Daniel A. Hammer

    Corresponding author
    1. School of Chemical Engineering, Cornell University, Ithaca, NY 14853
    • School of Chemical Engineering, Cornell University, Ithaca, NY 14853
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Abstract

The adhesion of biological cells to substrates is often mediated by binding between cellular receptors and substrate-bound ligand. In this work, we used a centrifugation assay to measure the adhesion of rat basophilic leukemia (RBL) cells coated with immunoglobulin E (IgE) to substrates coated with the ligand dinitrophenol (DNP). Increasing force, decreasing DNP substrate density, and decreasing cell surface IgE density all led to decreasing adhesion. Experiments performed at low IgE cell surface densities, in which few tethers from between cell and substrate suggest individual tethers have a binding strength of 2 to 4 microdyne, in agreement with previous measurements of the force to uproot receptors from the plasma membrane. We use this system to show how subpopulations expressing different numbers of cell surface receptors may be separated by exploiting their differential adhesiveness to substrates.

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