Donavan, GM and Lythe, GD (2016) T cell and reticular network co-dependence in HIV infection. Journal of Theoretical Biology, 395. pp. 211-220. ISSN 1095-8541
Abstract
Fibroblastic reticular cells (FRC) are arranged on a network in the T cell zone of lymph nodes, forming a scaffold for T cell migration, and providing survival factors, especially interleukin-7 (IL- 7). Conversely, CD4+ T cells are the major producers of lymphotoxin-_ (LT-_), necessary for the construction and maintenance of the FRC network. This interdependence creates the possibility of a vicious cycle, perpetuating loss of both FRC and T cells. Furthermore, evidence that HIV infection is responsible for collagenation of the network suggests that long term loss of network function might be responsible for the attenuated recovery in T cell count seen in HIV patients undergoing antiretroviral therapy (ART). We present computational and mathematical models of this interaction mechanism and subsequent naive CD4+ T-cell depletion in which (1) collagen deposition impedes access of naive T cells to IL-7 on the FRC and loss of IL-7 production by loss of FRC network itself, leading to the depletion of naive T cells through increased apoptosis; and (2) depletion of naive T cells as the source of LT-_ on which the FRC depend for survival, leads to loss of the network, thereby amplifying and perpetuating the cycle of depletion of both naive T cells and stromal cells. Our computational model explicitly includes an FRC network and its cytokine exchange with a heterogeneous T-cell population. We also derive lumped models, in terms of partial differential equations and reduced to ordinary differential equations, that provide additional insight into the mechanisms at work. The central conclusions are that 1) damage to the reticular network, caused by HIV infection, is a plausible mechanism for attenuated recovery post-ART; 2) within this, the production of T cell survival factors by FRCs may be the key rate-limiting step; and 3) the methods of model reduction and analysis presented are useful for both immunological studies and other contexts in which agent-based models are severely limited by computational cost.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2016, Elsevier Ltd. This is an author produced version of a paper published in Journal of Theoretical Biology. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | FRC network; Fibroblastic reticular cells; Lymphocyte |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Engineering & Physical Sciences (Leeds) > School of Mathematics (Leeds) > Applied Mathematics (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 08 Feb 2016 11:16 |
Last Modified: | 12 Apr 2017 17:27 |
Published Version: | http://dx.doi.org/10.1016/j.jtbi.2016.01.040 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.jtbi.2016.01.040 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:94739 |