This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Coombs, D. Articles by Goldstein, B. Search for Related Content PubMed PubMed Citation Articles by Coombs, D. Articles by Goldstein, B.

Effects of the Geometry of the Immunological Synapse on the Delivery of Effector Molecules

Daniel Coombs ^* and Byron Goldstein 

^* Department of Mathematics, University of British Columbia, Vancouver, British Columbia V6T 1Z2, Canada; and Theoretical Biology and Biophysics Group, MS K710, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA

Correspondence: Address reprint requests to Daniel Coombs, E-mail: coombs{at}math.ubc.ca.

Recent experiments focusing on the function of the immunological synapse formed between a T cell and an antigen-presenting cell raise many questions about its purpose. We examine the proposal that the close apposition of the cell membranes in the central region of the synapse acts to focus T-cell secretions on the target cell, thus reducing the effect on nearby cells. We show that the efficiency of targeted T-cell responses to closely apposed cells is only weakly dependent on the distance between the cells. We also calculate effective (diffusion-limited) rates of binding and unbinding for molecules secreted within the synapse. We apply our model to the stimulation of B cells by secreted interleukin-4 (IL-4), and find that very few molecules of IL-4 need be released to essentially saturate the IL-4 receptors on the B-cell surface.